Patent Application
20240206219
This application is based on and claims priority to Korean Patent Application No. 10-2022-0169101, filed on Dec. 6, 2022, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which is incorporated by reference herein in its entirety.
The disclosure relates to an electron transport layer including a mixed composition, a method of manufacturing a light-emitting device including the electron transport layer, and a light-emitting device and an electronic device each including the electron transport layer.
Light-emitting devices are devices that convert electrical energy into light energy. Examples of such light-emitting devices include organic light-emitting devices in which a light-emitting material is an organic material, and quantum dot light-emitting devices in which the light-emitting material is a quantum dot.
In a light-emitting device, a first electrode is located on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode are sequentially arranged on the first electrode. Holes provided from the first electrode move toward the emission layer through the hole transport region, and electrons provided from the second electrode move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state to thereby generate light.
Disclosed are an electron transport layer including a mixed composition, a method of manufacturing a light-emitting device including the electron transport layer, and a light-emitting device and an electronic device each including the electron transport layer. More specifically, disclosed are an electron transport layer including a mixed composition capable of reducing oxygen vacancy, a method of manufacturing a light-emitting device including the electron transport layer, and a light-emitting device and an electronic device each manufactured by using the method.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
Disclosed is an electron transport layer including a mixed composition including a solvent, a metal oxide, and a metal halogen compound.
In an embodiment, the metal oxide may be represented by Formula 1
M11-xM2xOy Formula 1
wherein, in Formula 1,
M1 and M2 may each independently include Zn, Mg, Co, Mn, Y, Al, Ti, Zr, Sn, W, Ta, Ni, Mo, Cu, Ag, In, Nb, Fe, Ce, Sr, Ba, Si, Ga, or a combination thereof,
x may be 0≤x≤1, and y may be 0<y≤5.
In an embodiment, the metal halogen compound may be represented by Formula 2
M3(X1)n1 Formula 2
wherein, in Formula 2,
X1 may be F, Cl, Br, I, or a combination thereof, and
n1 may be an integer from 1 to 3.
According to an embodiment, a method of manufacturing a light-emitting device includes disposing an emission layer including a quantum dot on a first electrode, disposing an electron transport layer by providing the mixed composition described above on the emission layer, and disposing a second electrode on the electron transport layer.
According to an embodiment, a light-emitting device includes a first electrode, a second electrode facing the first electrode, an emission layer disposed between the first electrode and the second electrode, and an electron transport layer disposed between the emission layer and the second electrode, wherein the electron transport layer includes a mixture of a metal oxide and a metal halogen compound.
According to an embodiment, an electronic device includes the light-emitting device.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain various aspects of the present description. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a”, “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to include both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise. “At least one” is not to be construed as limiting “a” or “an.” “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the disclosure, the expression “at least one of a, b or c” indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.
Because the disclosure may have diverse modified embodiments, embodiments are illustrated in the drawings and are described in the detailed description. An effect and a characteristic of the disclosure, and a method of accomplishing these will be apparent when referring to embodiments described with reference to the drawings. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Like reference numerals refer to like elements throughout.
It will be understood that although the terms “first,” “second,” etc. used herein may be used herein to describe various components, regions, layers and/or sections, these elements, components, regions, layers and/or sections, these components, regions, layers and/or sections, these elements, components, regions, layers and/or sections, should not be limited by these terms. These terms are only used to distinguish one component, element, region, layer or section, from another element, component, region, layer or section. Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein.
An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context.
It will be further understood that the terms “includes” and/or “comprises” used herein specify the presence of stated features or elements, but do not preclude the presence or addition of one or more other features or elements. Unless defined otherwise, the terms “include or have” may refer to both the case of consisting of features or components described in a specification and the case of further including other components.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a”, “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to include both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise. “At least one” is not to be construed as limiting “a” or “an.” “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10% or 5% of the stated value. Endpoints of ranges may each be independently selected.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.
The term “Group II” as used herein may include IIA Group elements and IIB Group elements in the IUPAC Periodic Table of Elements. Examples of the Group II element may include Cd, Mg, and Zn, but embodiments are not limited thereto.
The term “Group III” as used herein may include IIIA Group elements and IIIB Group elements in the IUPAC Periodic Table of Elements. Examples of the Group III element may include Al, In, Ga, and Tl, but embodiments are not limited thereto.
The term “Group IV” as used herein may include IVA Group elements and IVB Group elements in the IUPAC Periodic Table of Elements. Examples of the Group IV element may include Si, Ge, and Sn, but embodiments are not limited thereto.
The term “Group V” as used herein may include VA Group elements in the IUPAC Periodic Table of Elements. Examples of the group V element may include N, P, As, Sb, and Bi, but embodiments are not limited thereto. The term “Group VI” as used herein may include VIA Group elements in the IUPAC Periodic Table of Elements. Examples of the Group VI element may include O, S, Se, and Te, but embodiments are not limited thereto.
The term “metal” as used herein may include metalloid such as Si. Examples of the metalloid may include B, Si, Ge, As, Sb, Te, and the like.
Hereinafter, a mixed composition according to an embodiment may be described.
Hereinafter, a mixed composition according to an embodiment will be described with reference to
With reference to
The metal halogen compound 2 may include at least one metal atom 4 and at least one halogen atom 5.
That is, the mixed composition 3 may include the metal oxide 1, the metal atom 4, and the halogen atom 5.
The metal atom 4 may have a positive charge.
The halogen atom 5 may have a negative charge.
In an embodiment, the mixed composition may be amorphous, ionic, or may be both amorphous and ionic.
The term “amorphous” as used herein refers to a solid state in which there is no long-range order in positions of atoms. The term “ion” as used herein refers to a state in which atoms have an electric charge by losing or gaining an electron, and “ionic” as used herein refers to existing as an ion.
In an embodiment, the metal oxide 1 may be represented by Formula 1:
M11-xM2xOy Formula 1
wherein, in Formula 1,
M1 and M2 may each independently include Zn, Mg, Co, Mn, Y, Al, Ti, Zr, Sn, W, Ta, Ni, Mo, Cu, Ag, In, Nb, Fe, Ce, Sr, Ba, Si, Ga, or a combination thereof,
x may satisfy 0≤x≤1, and y may satisfy 0<y≤5.
In an embodiment, M1 may be Zn, and x may satisfy 0≤x≤0.5.
In an embodiment, the metal oxide 1 may include a zinc-containing oxide.
In an embodiment, the metal oxide 1 may be ZnO, TiO2, ZrO2, SnO2, WO3, W2O3, WO2, Ta2O5, NiO, MoO2, MoO3, CuO, Cu2O, ZnMgO, ZnCoO, ZnMnO, ZnSnO, ZnAlO, ZnSiO, ZnYbO, or a combination thereof.
In an embodiment, an average diameter (D50) of the metal oxide 1 may be in a range of about 1 nanometer (nm) to about 50 nm. The average diameter of the metal oxide may be measured by dynamic light scattering (DLS) method. An average diameter may be a mean diameter, or a median diameter, of the metal oxide measured by the DLS method.
For example, the metal oxide 1 may be in a spherical shape, for example, a substantially spherical shape.
In an embodiment, the metal halogen compound 2 may be represented by Formula 2
M3(X1)n1 Formula 2
wherein, in Formula 2,
M3 may be a metal,
X1 may be F, Cl, Br, I, or a combination thereof, and
n1 may be an integer from 1 to 3.
M3 may be Al, Zn, In, Ga, Ti, Mg, Li, Na, K, Rb, or Cs. M3 may be Al, Zn, In, Ga, Ti, Mg, or Li.
For example, M3 may be Al, and in this case, n1 may be 3.
In an embodiment, the metal halogen compound 2 may be AlF3, AlCl3, AlBr3, AlI3, or a combination thereof.
The mixed composition may be included in an electron transport region. For example, the mixed composition may be included in an electron transport layer.
The mixed composition may be used in a light-emitting device.
In the metal oxide 1 (e.g., a metal oxide nanoparticle), for example, the metal oxide nanoparticle such as ZnO, multiple oxygen vacancies may be present in a crystal thereof. Due to the oxygen vacancies inside the nanoparticle, the nanoparticle may be an n-type, and the nanoparticle may have a high electrical conductivity. In addition, an energy level of a conduction band of the metal oxide nanoparticle may be similar with an energy level of a conduction band of quantum dots. Thus, the metal oxide nanoparticle may have excellent electron injection characteristics, and a metal oxide layer including the metal oxide nanoparticle may be used as an electron injection layer or an electron transport layer in a quantum dot light-emitting device.
However, due to a change in the energy level caused by the oxygen vacancy on a surface of the metal oxide nanoparticle, the oxygen vacancy on the surface may serve as an electron trap. Accordingly, electrons injected from an electron injection electrode may be trapped on the surface of the metal oxide nanoparticle. Thus, the electrons may not be injected into an emission layer, and thus, electron injection and transport efficiency may be reduced. In addition, defect-assisted non-radiative recombination or Auger-type non-radiative recombination may occur in a quantum dot emission layer adjacent to the metal oxide layer, thus deteriorating luminescence efficiency.
As the mixed composition according to an embodiment includes the metal oxide and the metal halogen compound, and the metal halogen compound provides metal cations and halogen anions among metal oxides, the mixed composition may be an amorphous substance, an ion, or has a mixed form thereof. In an aspect, the mixed composition may be amorphous, ionic, or may be both amorphous and ionic.
As such, the metal cations are dispersed among the metal oxides, and accordingly, in the process of manufacturing a light-emitting device accompanied by a heat-treating process, an amorphous metal oxide may be formed, and a packing density of components in the electron transport layer may be increased, thereby facilitating control of hole leakage current.
Moreover, a number of electron trap sites of a surface of the halogen anions may be reduced, and accordingly, the efficiency in electron injection from the electron transport layer including the mixed composition to the emission layer may be increased. Furthermore, as exciton quenching generated in the emission layer is suppressed, efficiency of the light-emitting device may be improved.
Also, lifespan characteristics of the light-emitting device may be improved by fundamentally controlling the cause of deterioration occurring at an interface adjacent to the emission layer due to excessive charge injection.
Accordingly, the light-emitting device using the mixed composition may have excellent driving characteristics, for example, a low driving voltage, high efficiency, and/or long lifespan.
In an embodiment, an amount of the metal halogen compound in the mixed composition may be greater than or equal to about 0.1 part by weight and less than or equal to about 50 parts by weight, for example, greater than or equal to about 0.1 part by weight and less than or equal to about 50 parts by weight, greater than or equal to about 0.1 parts by weight and less than or equal to about 45 parts by weight, greater than or equal to about 0.1 part by weight and less than or equal to about 40 parts by weight, greater than or equal to about 0.1 part by weight and less than or equal to about 35 parts by weight, or greater than or equal to about 0.1 part by weight and less than or equal to about 30 parts by weight, based on 100 parts by weight of the metal oxide, but embodiments of the disclosure are not limited thereto.
In an embodiment, an amount of the metal oxide in the mixed composition may be greater than or equal to about 0.1 part by weight and less than or equal to about 50 parts by weight, for example, greater than or equal to about 0.1 part by weight and less than or equal to about 50 parts by weight, greater than or equal to about 0.5 part by weight and less than or equal to about 50 parts by weight, greater than or equal to about 0.1 part by weight and less than or equal to about 45 parts by weight, or greater than or equal to about 0.1 part by weight and less than or equal to about 40 parts by weight, based on 100 parts by weight of the solvent, but embodiments of the disclosure are not limited thereto.
The mixed composition may include a solvent. The solvent may be any suitable solvent that may properly disperse the metal oxide and the metal halogen compound, but embodiments are not limited thereto.
For example, the solvent may be an organic solvent.
In an embodiment, the solvent may bean alcohol (e.g., alcohol-based solvent), a halide such as a chloride (e.g., chlorine-based solvent), an ether (e.g., ether-based solvent), an ester (e.g., ester-based solvent), a ketone (e.g., ketone-based solvent), an aliphatic hydrocarbon (e.g., aliphatic hydrocarbon-based solvent), or an aromatic hydrocarbon (e.g., aromatic hydrocarbon-based organic solvent), but embodiments are not limited thereto. In an aspect, the solvent may comprise an alcohol, an ether, an ester, a ketone, an aliphatic hydrocarbon such as a C1 to C18 aliphatic hydrocarbon, an aromatic hydrocarbon such as a C6 to C20 aromatic hydrocarbon, or a combination thereof, wherein any of the foregoing may optionally be substituted with a halogen, such as chlorine.
In an embodiment, the solvent may include: an alcohol-based solvent such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, or t-butanol; a chlorine-based solvent such as dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, or o-dichlorobenzene; an ether-based solvent such as tetrahydrofuran, dioxane, anisol, 4-methylanisol, or butyl phenylether; an ester-based solvent such as acetateethyl, acetatebutyl, methyl benzoate, ethyl benzoate, butyl benzoate, or phenyl benzoate; a ketone-based solvent such as acetone, methylethylketone, cyclohexanone, or acetophenone; an aliphatic hydrocarbon-based solvent such as cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, dodecane, hexadecane, or oxadecane; an aromatic hydrocarbon-based solvent such as toluene, xylene, mesitylene, ethylbenzene, n-hexyl benzene, cyclohexyl benzene, trimethyl benzene, tetrahydronaphthalene; or a combination thereof, but embodiments are not limited thereto.
A content of the solvent in the mixed composition may be about 80 weight percent (wt %) or greater and about 99.5 wt % or less, or for example, about 90 wt % or greater and 99 wt % or less, about 92 wt % or greater and 98 wt % or less, but embodiments are not limited thereto. When the content is within any of these ranges, the metal oxide and the metal halogen compound in the mixed composition may be properly dispersed, and the solid concentration may be suitable for a solution process.
The mixed composition may have a viscosity of about 1 centipoise (cP) to about 30 cP. A mixed composition that satisfies the viscosity range may be suitable for manufacturing an electron transport layer of a light-emitting device by using a soluble process.
A surface tension of the mixed composition may be from about 10 dynes per centimeter (dynes/cm) to about 40 dynes/cm. A mixed composition that satisfies the surface tension range may be suitable for manufacturing an electron transport layer of a light-emitting device by using a soluble process.
A method of manufacturing a light-emitting device may include: disposing (e.g., forming) an emission layer including a quantum dot on a first electrode;
forming an electron transport layer by providing the mixed composition described above on the emission layer, and
forming a second electrode on the electron transport layer to manufacture the light- emitting device.
In an embodiment, the disposing of the emission layer may include providing, on the first electrode, a quantum dot composition including quantum dots and a solvent, and removing the solvent.
After the quantum dot composition is provided on the first electrode, the solvent may be removed by vacuum or heat to form an emission layer, but embodiments are not limited thereto.
For example, the removing of the solvent may be performed at a predetermined temperature, for example, at about 50° C. to about 150° C. For example, heat-treating may be performed under vacuum.
The quantum dot composition may be provided on the first electrode to a thickness of about 10 nm to about 100 nm.
In an embodiment, the forming of the electron transport layer may include: providing, on the emission layer, the mixed composition described above; and removing the solvent.
In an embodiment, the forming of the electron transport layer may include: providing a first composition including the metal oxide and the solvent on the emission layer; providing a second composition comprising the metal halogen compound and the solvent on the first composition; and removing the solvent.
After the mixed composition is provided on the emission layer, the solvent may be removed by vacuum or heat to form an electron transport layer, but embodiments are not limited thereto.
For example, the removing of the solvent may be performed at a predetermined temperature, for example, at about 50° C. to about 150° C. For example, heat-treating may be performed under vacuum.
The quantum dot composition and the mixed composition may be provided on the first electrode by using a solution process, but embodiments are not limited thereto. For example, the solution process may be an inkjet printing process, a drop casting process, a spin coating process, a dip coating process, a spray coating process, a flow coating process, or a screen printing process, but embodiments of the disclosure are not limited thereto.
The solvent may include an organic solvent as described above.
In some embodiments, the solution process may be performed by a spin coating method, a casting method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a spray coating method, a screen coating method, a flexoprinting method, an offset printing method, an inkjet printing method, or a nozzle printing method, but embodiments are not limited thereto.
In an embodiment, the method may further include, after forming the second electrode, heat-treating the first electrode, the emission layer, the electron transport layer, and the second electrode, at about 50° C. to about 250° C., at about 50° C. to about 200° C., or at about 100° C. to about 150° C. By additionally heat-treating the light-emitting device, the metal cations and halogen anions discharged from the metal halogen compound may be located among metal oxides, thereby forming an amorphous metal oxide. Accordingly, the packing density of components in the electron transport layer may be further increased, which leads to improved efficiency and lifespan characteristics.
For example, the heat-treating may be performed for about 1 hour to about 240 hours.
The light-emitting device may include: a first electrode; a second electrode facing the first electrode; an emission layer disposed (e.g., arranged) between the first electrode and the second electrode; and an electron transport layer arranged between the emission layer the second electrode, wherein the electron transport layer may include a mixture of a metal oxide and a metal halogen compound.
In an embodiment, the electron transport layer may have a single-layer structure.
In an embodiment, the metal oxide and the metal halogen compound in the electron transport layer may be homogeneous.
In an embodiment, a degree of dispersion of the metal oxide in the electron transport layer may increase or decrease towards the emission layer. For example, a concentration gradient of the metal oxide in the electron transport layer may be implemented through a multi-layer lamination process; however, the disclosure is not limited thereto.
In an embodiment, a degree of dispersion of the metal halogen compound in the electron transport layer may increase or decrease towards the emission layer. For example, a concentration gradient of the metal halogen compound in the electron transport layer may be implemented through a multi-layer lamination process; however, the disclosure is not limited thereto.
In an embodiment, the emission layer may include a quantum dot.
The term “quantum dot” as used herein refers to a crystal of a semiconductor compound, and may include any suitable material capable of emitting light of various emission wavelengths according to the size of the crystal.
The quantum dots included in the emission layer may include a Group II-VI semiconductor compound, a Group III-V semiconductor compound, a Group III-VI semiconductor compound, a Group I-III-VI semiconductor compound, a Group IV-VI semiconductor compound, a Group IV element or compound, or a combination thereof.
Examples of the Group II-VI semiconductor compound may include a binary compound such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, or MgS; a ternary compound such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, or MgZnS; a quaternary compound such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or HgZnSTe; or a combination thereof.
Examples of the Group III-V semiconductor compound may include a binary compound such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, or InSb; a ternary compound such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, or InPSb; a quaternary compound such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, or InAlPSb; or a combination thereof. In an embodiment, the Group III-V semiconductor compound may further include a Group II element. Examples of the Group III-V semiconductor compound further including the Group II element may include InZnP, InGaZnP, InAlZnP, and the like.
Examples of the Group III-VI semiconductor compound are: a binary compound, such as GaS, GaSe, GazSes, GaTe, InS, InSe, In2S3, In2Se3, or InTe; a ternary compound, such as InGaS3, or InGaSe3; or a combination thereof.
Examples of the Group I-III-VI semiconductor compound may include a ternary compound such as AgInS, AgInS2, CuInS, CuInS2, CuGaO2, AgGaO2, or AgAlO2; or a combination thereof.
Examples of the Group IV-VI semiconductor compound may include: a binary compound such as SnS, SnSe, SnTe, PbS, PbSe, or PbTe; a ternary compound such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, or SnPbTe; a quaternary compound such as SnPbSSe, SnPbSeTe, or SnPbSTe; or a combination thereof.
The Group IV element or compound may be: a single element material such as Si or Ge; a binary compound such as SiC or SiGe; or a combination thereof.
Each element included in a multi-element compound such as the binary compound, the ternary compound, and the quaternary compound may be present at a uniform concentration or non-uniform concentration in a particle.
Meanwhile, the quantum dot may have a single structure in which the concentration of each element in the quantum dot is uniform, or a core-shell dual structure. For example, the material included in the core and the material included in the shell may be different from each other.
In an embodiment, the core may include Zn, Te, Se, Cd, In, P, or a combination thereof. For example, the core may include InP, InZnP, ZnSe, ZnTeS, ZnSeTe, or a combination thereof.
The shell of the quantum dot may act as a protective layer that prevents chemical degeneration of the core to maintain semiconductor characteristics, and/or as a charging layer that imparts electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. An interface between the core and the shell may have a concentration gradient in which the concentration of an element existing in the shell decreases toward the center of the core.
Examples of the shell of the quantum dot may be an oxide of metal, metalloid, or non-metal, a semiconductor compound, or a combination thereof. Examples of the oxide of metal, metalloid, or non-metal are a binary compound, such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, or NiO; a ternary compound, such as MgAl2O4, CoFe2O4, NiFe2O4, or CoMn2O4; or a combination thereof. Examples of the semiconductor compound may include a Group II-VI semiconductor compound, a Group III-V semiconductor compound, a Group III-VI semiconductor compound, a Group I-III-VI semiconductor compound, a Group IV-VI semiconductor compound, or a combination thereof. In an embodiment, the semiconductor compound may be CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, ZnSeTe, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or a combination thereof.
In an embodiment, the shell may have a composition different from the composition of the core, and the shell may include ZnS, ZnSe, ZnSeS, ZnTeS, ZnSeTe, or a combination thereof.
The quantum dots may each have a full width at half maximum (FWHM) of a peak of an emission wavelength of about 45 nm or less, about 40 nm or less, or about 30 nm or less. When the FWHM of the quantum dot is within this range, color purity or color reproducibility may be improved. In addition, since a light emitted through the quantum dot is emitted in all directions, the wide viewing angle may be improved.
In an embodiment, a diameter of the quantum dot may be in a range of about 1 nm to about 20 nm. When the average diameter of the quantum dots is within any of these ranges, specific behavior as quantum dots may be achieved, and excellent dispersibility of the composition may be obtained. The average diameter of the quantum dots may be measured by dynamic light scattering (DLS) method. An average diameter may be a mean diameter, or a median diameter, of the quantum dot measured by the DLS method. In addition, the quantum dot may be in a form of a spherical particle, a pyramidal particle, a multi-arm particle, a cubic nanoparticle, a nanotube particle, a nanowire particle, a nanofiber particle, or a nanoplate particle.
Since the energy band gap may be adjusted by controlling the size (e.g., diameter) of the quantum dot, light having various wavelength bands may be obtained from the quantum dot emission layer. Accordingly, by using quantum dots of different sizes, a light-emitting device that emits light of various wavelengths may be implemented. In an embodiment, the size of the quantum dot may be selected to emit red, green and/or blue light. In addition, the size of the quantum dot may be configured to emit white light by a combination of light of various colors.
The quantum dot may be synthesized by a wet chemical process, a metal organic chemical vapor deposition process, a molecular beam epitaxy process, or any suitable process similar thereto.
The wet chemical process is a method including mixing a precursor material with an organic solvent and then growing a quantum dot particle crystal. When the crystal grows, the organic solvent naturally acts as a dispersant coordinated on the surface of the quantum dot crystal and controls the growth of the crystal so that the growth of quantum dot particles can be controlled through a process which costs lower, and is easier than vapor deposition methods, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).
In an embodiment, the emission layer may include a monolayer of quantum dots. In an embodiment, the emission layer may include a monolayer of quantum dots from about 2 layers to about 20 layers.
A thickness of the emission layer may be in a range of about 5 nm to about 200 nm, about 10 nm to about 150 nm, or for example, about 10 nm to about 100 nm.
For example, the electron transport layer may be a layer formed using a mixed composition according to an embodiment.
In an embodiment, the first electrode may be an anode, the second electrode may be a cathode, the light-emitting device may further include a hole transport region arranged between the first electrode and the emission layer and an electron transport region arranged between the emission layer and the second electrode, and the electron transport region may include the electron transport layer.
The electron transport region may include a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or a combination thereof. The electron transport layer may be the buffer layer, the hole blocking layer, the electron transport layer, the electron injection layer, or a combination thereof.
A thickness of the electron transport layer may be in a range of about 2 nm to about 250 nm, about 10 nm to about 200 nm, or for example, about 5 nm to about 250 nm. Accordingly, upon formation of the second electrode, damage to the emission layer may be prevented.
In an embodiment, in the electron transport layer, a metal halogen compound, i.e., metal cations and halogen anions may be present between particles of the metal oxide.
In an embodiment, the metal oxide may be a zinc-containing oxide.
In an embodiment, the metal oxide may be ZnO, TiO2, ZrO2, SnO2, WO3, W2O3, WO2, Ta2O5, NiO, MoO2, MoOs, CuO, Cu2O, ZnMgO, ZnCoO, ZnMnO, ZnSnO, ZnAlO, ZnSiO, ZnYbO, or a combination thereof.
Due to the metal halogen compound included in the electron transport layer, in the process of manufacturing a light-emitting device accompanied by a heat-treating process, an amorphous metal oxide may be formed, and a packing density of components in the electron transport layer may be increased, thereby facilitating control of hole leakage current. In addition, a number of electron trap sites of a surface of the metal oxide may be reduced, which leads to improved efficiency in electron injection from the electron transport layer including the mixed composition to the emission layer.
Accordingly, the light-emitting device may exhibit excellent driving characteristics, e.g., a low driving voltage, high efficiency, and/or long lifespan.
Hereinafter, the structure of the light-emitting device 10 according to an embodiment and a method of manufacturing the light-emitting device 10 will be described in connection with
In
The first electrode 110 may be formed by, for example, depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, a material for forming the first electrode 110 may be a high-work function material that facilitates injection of holes.
The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming the first electrode 110 may include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), or a combination thereof. In an embodiment, when the first electrode 110 is a semi-transmissive electrode or a reflective electrode, a material for forming the first electrode 110 may include magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or a combination thereof.
The first electrode 110 may have a single-layered structure consisting of a single layer or a multi-layered structure including a plurality of layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO.
The interlayer 130 may be disposed (e.g., located) on the first electrode 110. The interlayer 130 may include an emission layer.
The interlayer 130 may further include a hole transport region located between the first electrode 110 and the emission layer, and an electron transport region located between the emission layer and the second electrode 150.
The interlayer 130 may further include metal-containing compounds such as organometallic compounds, inorganic materials such as quantum dots, and the like, in addition to various organic materials.
In an embodiment, the interlayer 130 may include, i) two or more emitting units sequentially stacked between the first electrode 110 and the second electrode 150, and ii) a charge generation layer located between the two or more emitting units. When the interlayer 130 includes emitting units and a charge generation layer as described above, the light-emitting device 10 may be a tandem light-emitting device.
The hole transport region may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.
The hole transport region may include a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or a combination thereof.
For example, the hole transport region may have a multi-layered structure including a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, the layers of each structure being stacked sequentially from the first electrode 110.
The hole transport region may include a compound represented by Formula 201, a compound represented by Formula 202, or a combination thereof:
wherein, in Formulae 201 and 202,
L201 to L204 may each independently be a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a,
L205 may be *—O—** , *—S—** , *—N(Q201)—*′, a C1-C20 alkylene group unsubstituted or substituted with at least one R10a, a C2-C20 alkenylene group unsubstituted or substituted with at least one R10a, a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a, or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a,
xa1 to xa4 may each independently be an integer from 0 to 5,
xa5 may be an integer from 1 to 10,
R201 to R204 and Q201 may each independently be a C3-C6 carbocyclic group unsubstituted or substituted with at least one R10a, or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a,
R201 and R202 may optionally be linked to each other via a single bond, a C1-C5 alkylene group unsubstituted or substituted with at least one R10a, or a C2-C5 alkenylene group unsubstituted or substituted with at least one R10a, to form a C8-C60 polycyclic group (for example, a carbazole group) unsubstituted or substituted with at least one R10a (for example, Compound HT16),
R203 and R204 may optionally be linked to each other via a single bond, a C1-C5 alkylene group unsubstituted or substituted with at least one R10a, or a C2-C5 alkenylene group unsubstituted or substituted with at least one R10a, to form a C8-C60 polycyclic group unsubstituted or substituted with at least one R10a, and
na1 may be an integer from 1 to 4.
For example, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY217:
In Formulae CY201 to CY217, R10b and R10c may each be the same as described with respect to R10a, ring CY201 to ring CY204 may each independently be a C3-C20 carbocyclic group or a C1-C20 heterocyclic group, and at least one hydrogen in Formulae CY201 to CY217 may be unsubstituted or substituted with R10a as described above.
In an embodiment, ring CY201 to ring CY204 in Formulae CY201 to CY217 may each independently be a benzene group, a naphthalene group, a phenanthrene group, or an anthracene group.
In an embodiment, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY203.
In an embodiment, Formula 201 may include at least one of the groups represented by Formulae CY201 to CY203 and at least one of the groups represented by Formulae CY204 to CY217.
In an embodiment, in Formula 201, xa1 may be 1, R201 may be a group represented by one of Formulae CY201 to CY203, xa2 may be 0, and R202 may be a group represented by one of Formulae CY204 to CY207.
In an embodiment, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY203.
In an embodiment, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY203, and may include at least one of the groups represented by Formulae CY204 to CY217.
In an embodiment, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY217.
In an embodiment, the hole transport region may include one of Compounds HT1 to HT46, N1-phenyl-N4,N4-bis(4-(phenyl(m-tolyl)amino)phenyl)-N1-(m-tolyl)benzene-1,4-diamine (m-MTDATA), 1-N, 1-N-bis[4-(diphenylamino)phenyl]-4-N,4-N-diphenylbenzene-1,4-diamine (TDATA), 4,4′,4″-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), N,N′-di(1-naphthyl)-N, N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB, or NPD), β-NPB, N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD), Spiro-TPD, Spiro-NPB, methylated NPB, 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N,N′,N′-Tetra-(3-methylphenyl)-3,3′-dimethy Ibenzidine (HMTPD), 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), or a combination thereof:
A thickness of the hole transport region may be in a range of about 50 angstroms (Å) to about 10,000 Å, for example, about 100 Å to about 4,000 Å. When the hole transport region includes a hole injection layer, a hole transport layer, or a combination thereof, a thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, for example, about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.
The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer, and the electron blocking layer may block the leakage of electrons from an emission layer to a hole transport region. Materials that may be included in the hole transport region may be included in the emission auxiliary layer and the electron blocking layer.
The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be uniformly or non-uniformly dispersed in the hole transport region (for example, in a form of a single layer comprising a charge-generation material).
The charge-generation material may be, for example, a p-dopant.
For example, the lowest unoccupied molecular orbital (LUMO) energy level of the p-dopant may be about −3.5 electronvolts (eV) or less.
In an embodiment, the p-dopant may include a quinone derivative, a cyano group-containing compound, a compound including element EL1 and element EL2, or a combination thereof.
Examples of the quinone derivative are 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), etc.
Examples of the cyano group-containing compound are 1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile (HAT-CN), and a compound represented by Formula 221 below:
In Formula 221,
R221 to R223 may each independently be a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a, and
at least one of R221 to R223 may each independently be a C3-C60 carbocyclic group or a C1-C60 heterocyclic group, each substituted with a cyano group; —F; —Cl; —Br; —I; a C1-C20 alkyl group substituted with a cyano group, —F, —Cl, —Br, —I, or any combination thereof; or a combination thereof.
In the compound including element EL1 and element EL2, element EL1 may be metal, metalloid, or a combination thereof, and element EL2 may be non-metal, metalloid, or a combination thereof.
Examples of the metal are an alkali metal (for example, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), etc.); alkaline earth metal (for example, beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), etc.); transition metal (for example, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), etc.); post-transition metal (for example, zinc (Zn), indium (In), tin (Sn), etc.); and lanthanide metal (for example, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.).
Examples of the metalloid are silicon (Si), antimony (Sb), and tellurium (Te).
Examples of the non-metal are oxygen (O) and halogen (for example, F, Cl, Br, I, etc.).
Examples of the compound including element EL1 and element EL2 are metal oxide, metal halide (for example, metal fluoride, metal chloride, metal bromide, or metal iodide), metalloid halide (for example, metalloid fluoride, metalloid chloride, metalloid bromide, or metalloid iodide), metal telluride, or a combination thereof.
Examples of the metal oxide are tungsten oxide (for example, WO, W2O3, WO2, WO3, W2O5, etc.), vanadium oxide (for example, VO, V2O3, VO2, V2O5, etc.), molybdenum oxide (MoO, Mo2O3, MoO2, MoO3, Mo2O5, etc.), and rhenium oxide (for example, ReO3, etc.).
Examples of the metal halide are alkali metal halide, alkaline earth metal halide, transition metal halide, post-transition metal halide, and lanthanide metal halide.
Examples of the alkali metal halide are LiF, NaF, KF, RbF, CsF, LiCl, NaCl, KCl, RbCl, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, KI, RbI, CsI, and the like.
Examples of the alkaline earth metal halide are BeF2, MgF2, CaF2, SrF2, BaF2, BeCl2, MgCl2, CaCl2, SrCl2, BaCl2, BeBr2, MgBr2, CaBr2, SrBr2, BaBr2, BeI2, MgI2, CaI2, SrI2, and BaI2.
Examples of the transition metal halide are titanium halide (for example, TiF4, TiCl4, TiBr4, TiI4, etc.), zirconium halide (for example, ZrF4, ZrCl4, ZrBr4, ZrI4, etc.), hafnium halide (for example, HfF4, HfCl4, HfBr4, HfI4, etc.), vanadium halide (for example, VF3, VCl3, VBr3, VI3, etc.), niobium halide (for example, NbF3, NbCl3, NbBr3, NbI3, etc.), tantalum halide (for example, TaF3, TaCl3, TaBr3, TaI3, etc.), chromium halide (for example, CrF3, CrCl3, CrBr3, CrI3, etc.), molybdenum halide (for example, MoF3, MoCl3, MoBr3, MoI3, etc.), tungsten halide (for example, WF3, WCl3, WBr3, WI3, etc.), manganese halide (for example, MnF2, MnCl2, MnBr2, MnI2, etc.), technetium halide (for example, TcF2, TcCl2, TcBr2, TcI2, etc.), rhenium halide (for example, ReF2, ReCl2, ReBr2, ReI2, etc.), iron halide (for example, FeF2, FeCl2, FeBr2, FeI2, etc.), ruthenium halide (for example, RuF2, RuCl2, RuBr2, RuI2, etc.), osmium halide (for example, OsF2, OsCl2, OsBr2, OsI2, etc.), cobalt halide (for example, CoF2, CoCl2, CoBr2, CoI2, etc.), rhodium halide (for example, RhF2, RhCl2, RhBr2, RhI2, etc.), iridium halide (for example, IrF2, IrCl2, IrBr2, IrI2, etc.), nickel halide (for example, NiF2, NiCl2, NiBr2, NiI2, etc.), palladium halide (for example, PdF2, PdCl2, PdBr2, PdI2, etc.), platinum halide (for example, PtF2, PtCl2, PtBr2, PtI2, etc.), copper halide (for example, CuF, CuCl, CuBr, CuI, etc.), silver halide (for example, AgF, AgCl, AgBr, AgI, etc.), and gold halide (for example, AuF, AuCl, AuBr, AuI, etc.).
Examples of the post-transition metal halide are zinc halide (for example, ZnF2, ZnCl2, ZnBr2, ZnI2, etc.), indium halide (for example, InI3, etc.), and tin halide (for example, SnI2, etc.).
Examples of the lanthanide metal halide are YbF, YbF2, YbF3, SmF3, YbCl, YbCl2, YbCl3 SmCl3, YbBr, YbBr2, YbBr3 SmBr3, YbI, YbI2, YbI3, and SmI3.
Examples of the metalloid halide are antimony halide (for example, SbCl5 and the like) and the like.
Examples of the metal telluride are alkali metal telluride (for example, Li2Te, Na2Te, K2Te, Rb2Te, Cs2Te, etc.), alkaline earth metal telluride (for example, BeTe, MgTe, CaTe, SrTe, BaTe, etc.), transition metal telluride (for example, TiTe2, ZrTe2, HfTe2, V2Te3, Nb2Te3, Ta2Te3, Cr2Te3, Mo2Te3, W2Te3, MnTe, TcTe, ReTe, FeTe, RuTe, OsTe, CoTe, RhTe, IrTe, NiTe, PdTe, PtTe, CuzTe, CuTe, Ag2Te, AgTe, Au2Te, etc.), post-transition metal telluride (for example, ZnTe, etc.), and lanthanide metal telluride (for example, LaTe, CeTe, PrTe, NdTe, PmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, etc.).
When the light-emitting device 10 is a full-color light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to a sub-pixel. At least one of the emission layers may include the quantum dot described above. For example, the green emission layer may be a quantum dot emission layer including the quantum dot, and the blue emission layer and the red emission layer may each be an organic emission layer each including an organic compound.
In an embodiment, the emission layer may have a structure in which at least two of a red emission layer, a green emission layer, or a blue emission layer, may contact each other, or may be separated from each other. At least one emission layer of the at least two emission layers may be a quantum dot emission layer including the quantum dots, and the other emission layer may be an organic emission layer including organic compounds. Such a variation may be made.
The electron transport region may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.
Also, the electron transport region may further include a metal oxide layer in addition to the materials described above.
The electron transport region may include, for example, ZnO, TiO2, WO3, SnO2, In2O3, Nb2O5, Fe2O3, CeO2, SrTiO3, Zn2SnO4, BaSnO3, In2S3, ZnSiO, [6,6]-Phenyl-C61- butyric acid methyl ester (PC60BM), [6,6]-Phenyl-C71-butyric acid methyl ester (PC70BM), ZnMgO, AZO, GZO, IZO, Al-doped TiO2, Ga-doped TiO2, In-doped TiO2, Al-doped WO3, Ga-doped WO3, In-doped WO3, Al-doped SnO2, Ga-doped SnO2, In-doped SnO2, Mg-doped In2O3, Al-doped In2O3, Ga-doped In2O3, Mg-doped Nb2O5, Al-doped Nb2O5, Ga-doped Nb2O5, Mg-doped Fe2O3, Al-doped Fe2O3, Ga-doped Fe2O3, In-doped Fe2O3, Mg-doped CeO2, Al-doped CeO2, Ga-doped CeO2, In-doped CeO2, Mg-doped SrTiO3, Al-doped SrTiO3, Ga-doped SrTiO3, In-doped SrTiO3, Mg-doped Zn2SnO4, Al-doped Zn2SnO4, Ga-doped Zn2SnO4, In-doped Zn2SnO4, Mg-doped BaSnO3, Al-doped BaSnO3, Ga-doped BaSnO3, In-doped BaSnO3, Mg-doped In2S3, Al-doped In2S3, Ga-doped In2S3, In-doped In2S3, Mg-doped ZnSiO, Al-doped ZnSiO, Ga-doped ZnSiO, In-doped ZnSiO, or a combination thereof.
The electron transport region may include a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or a combination thereof. The buffer layer, the hole blocking layer, the electron control layer, the electron transport layer, or the electron injection layer may each be the metal oxide layer, or a combination of at least one layer of the buffer layer, the hole blocking layer, or the electron control layer, and the electron transport layer may be the metal oxide layer.
For example, the electron transport region may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, the constituting layers of each structure being sequentially stacked from an emission layer.
The electron transport region (for example, the buffer layer, the hole blocking layer, the electron control layer, or the electron transport layer in the electron transport region) may include the metal oxide described above.
The electron transport region (for example, the buffer layer, the hole blocking layer, the electron control layer, or the electron transport layer in the electron transport region) may include an organic material. For example, the electron transport region may include a metal-free compound including at least one π electron-depleted nitrogen-containing C1-C60 cyclic group.
For example, the electron transport region may include a compound represented by Formula 601:
[Ar601]xe11-[(L601) xe1-R601]xe21 Formula 601
wherein, in Formula 601,
Ar601 and L601 may each independently be a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a,
xe11 may be 1, 2, or 3,
xe1 may be 0, 1, 2, 3, 4, or 5,
R601 may be a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a, a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a, —Si(Q601)(Q602)(Q603), —C(═O)(Q601), —S(═O)2(Q601), or —P(═O)(Q601)(Q602),
Q601 to Q603 may each be the same as described herein with respect to Q1,
xe21 may be 1, 2, 3, 4, or 5, and
at least one of Ar601, L601, and R601 may each independently be a π electron-deficient nitrogen-containing C1-C60 cyclic group unsubstituted or substituted with at least one R10a.
For example, when xe11 in Formula 601 is 2 or more, two or more of Ar601(s) may be linked to each other via a single bond.
In an embodiment, Ar601 in Formula 601 may be a substituted or unsubstituted anthracene group.
In an embodiment, the electron transport region may include a compound represented by Formula 601-1:
wherein, in Formula 601-1,
X614 may be N or C(R614), X615 may be N or C(R615), X616 may be N or C(R616), and at least one of X614 to X616 may be N,
L611 to L613 may each be the same as described herein with respect to L601,
xe611 to xe613 may each be the same as described herein with respect to xe1,
R611 to R613 may each be the same as described herein with respect to R601, and
R614 to R616 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a, or a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a.
For example, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.
The electron transport region may include one of Compounds ET1 to ET45, 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), tris(8-hydroxyquinoline)aluminum(III) (Alq3), bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy) aluminum (BAlq), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), or a combination thereof:
A thickness of the electron transport region may be from about 100 Å to about 5,000 Å, for example, about 160 Å to about 4,000 Å. When the electron transport region includes a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, or a combination thereof, the thickness of the buffer layer, the hole blocking layer, or the electron control layer may each independently be from about 20 521 to about 1,000 Å, for example, about 30 Å to about 300 Å, and the thickness of the electron transport layer may be from about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the buffer layer, the hole blocking layer, the electron control layer, the electron transport layer, and/or the electron transport layer are within these ranges, satisfactory electron transporting characteristics may be obtained without a substantial increase in driving voltage.
The electron transport region (for example, the electron transport layer in the electron transport region) may further include, in addition to the materials described above, a metal-containing material.
The metal-containing material may include an alkali metal complex, an alkaline earth metal complex, or a combination thereof. The metal ion of an alkali metal complex may be a Li ion, a Na ion, a K ion, a Rb ion, or a Cs ion, and the metal ion of an alkaline earth metal complex may be a Be ion, a Mg ion, a Ca ion, a Sr ion, or a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex, or the alkaline earth-metal complex may include a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenylbenzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or a combination thereof.
For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (LiQ) or ET-D2:
The electron transport region may include an electron injection layer that facilitates the injection of electrons from the second electrode 150. The electron injection layer may directly contact the second electrode 150.
The electron injection layer may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.
The electron injection layer may include an alkali metal, alkaline earth metal, a rare earth metal, an alkali metal-containing compound, alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or a combination thereof.
The alkali metal may include Li, Na, K, Rb, Cs, or a combination thereof. The alkaline earth metal may include Mg, Ca, Sr, Ba, or a combination thereof. The rare earth metal may include Sc, Y, Ce, Tb, Yb, Gd, or a combination thereof.
The alkali metal-containing compound, the alkaline earth metal-containing compound, and the rare earth metal-containing compound may be oxides, halides (for example, fluorides, chlorides, bromides, or iodides), or tellurides of the alkali metal, the alkaline earth metal, and the rare earth metal, or a combination thereof.
The alkali metal-containing compound may include: alkali metal oxides, such as Li2O, Cs2O, or K2O; alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI; or a combination thereof. The alkaline earth metal-containing compound may include an alkaline earth metal compound, such as BaO, SrO, CaO, BaxSr1-xO (wherein x is a real number satisfying the condition of 0<x<1), BaxCa1-xO (wherein x is a real number satisfying the condition of 0<x<1), or the like. The rare earth metal-containing compound may include YbF3, ScF3, Sc2O3, Y2O3, Ce2O3, GdF3, TbF3, YbI3, ScI3, TbI3, or any combination thereof. In an embodiment, the rare earth metal-containing compound may include lanthanide metal telluride. Examples of the lanthanide metal telluride are LaTe, CeTe, PrTe, NdTe, PmTe, SmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe,LuTe, La2Te3, Ce2Te3, Pr2Te3, Nd2Te3, Pm2Te3, Sm2Te3, Eu2Te3, Gd2Te3, Tb2Te3, Dy2Te3, Ho2Te3, Er2Te3, Tm2Te3, Yb2Te3, and Lu2Te3.
The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include i) one of ions of the alkali metal, the alkaline earth metal, or the rare earth metal and ii) a ligand bonded to the metal ion, for example, hydroxyquinoline, hydroxyisoquinoline, hydroxybenzoquinoline, hydroxyacridine, hydroxyphenanthridine, hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxyphenyloxadiazole, hydroxyphenylthiadiazole, hydroxyphenylpyridine, hydroxyphenyl benzimidazole, hydroxyphenylbenzothiazole, bipyridine, phenanthroline, cyclopentadiene, or a combination thereof.
The electron injection layer may comprise an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or a combination thereof, as described above. In an embodiment, the electron injection layer may further include an organic material (for example, a compound represented by Formula 601).
In an embodiment, the electron injection layer may comprise: i) an alkali metal-containing compound (for example, an alkali metal halide); or ii) a) an alkali metal-containing compound (for example, an alkali metal halide), and b) an alkali metal, an alkaline earth metal, a rare earth metal, or a combination thereof. For example, the electron injection layer may be a KI:Yb co-deposited layer, an RbI:Yb co-deposited layer, or the like.
When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or a combination thereof may be uniformly or non-uniformly dispersed in a matrix including the organic material.
A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the ranges described above, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.
The second electrode 150 may be located on the interlayer 130 having a structure as described above. The second electrode 150 may be a cathode, which is an electron injection electrode, and as the material for the second electrode 150, a metal, an alloy, an electrically conductive compound, or a combination thereof, each having a low-work function, may be used.
The second electrode 150 may include lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), ytterbium (Yb), silver-ytterbium (Ag-Yb), ITO, IZO, or a combination thereof. The second electrode 150 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.
The second electrode 150 may have a single-layered structure or a multi-layered structure including a plurality of layers.
A first capping layer may be located outside the first electrode 110, and/or a second capping layer may be located outside the second electrode 150. In particular, the light-emitting device 10 may have a structure in which the first capping layer, the first electrode 110, the interlayer 130, and the second electrode 150 are sequentially stacked in the stated order, a structure in which the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in the stated order, or a structure in which the first capping layer, the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in the stated order.
Light generated in an emission layer of the interlayer 130 of the light-emitting device 10 may be extracted toward the outside through the first electrode 110 which is a semi-transmissive electrode or a transmissive electrode, and the first capping layer. Light generated in an emission layer of the interlayer 130 of the light-emitting device 10 may be extracted toward the outside through the second electrode 150 which is a semi-transmissive electrode or a transmissive electrode, and the second capping layer.
The first capping layer and the second capping layer may increase external emission efficiency according to the principle of constructive interference. Accordingly, the light extraction efficiency of the light-emitting device 10 is increased, so that the luminescence efficiency of the light-emitting device 10 may be improved.
Each of the first capping layer and the second capping layer may include a material having a refractive index of about 1.6 or greater (at 589 nm).
The first capping layer and the second capping layer may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or an organic-inorganic composite capping layer including an organic material and an inorganic material.
At least one of the first capping layer and the second capping layer may each independently include carbocyclic compounds, heterocyclic compounds, amine group-containing compounds, porphine derivatives, phthalocyanine derivatives, a naphthalocyanine derivatives, alkali metal complexes, alkaline earth metal complexes, or a combination thereof. Optionally, the carbocyclic compound, the heterocyclic compound, and the amine group-containing compound may be substituted with a substituent including O, N, S, Se, Si, F, Cl, Br, I, or a combination thereof. In an embodiment, at least one of the first capping layer and the second capping layer may each independently include an amine group-containing compound.
For example, at least one of the first capping layer and the second capping layer may each independently include a compound represented by Formula 201, a compound represented by Formula 202, or a combination thereof.
In an embodiment, at least one of the first capping layer and the second capping layer may each independently include one of Compounds HT28 to HT33, one of Compounds CP1 to CP6, β-NPB, or a combination thereof:
The light-emitting device 10 may be included in various electronic devices. In an embodiment, an electronic device including the light-emitting device 10 may be an emission apparatus or an authentication apparatus.
The electronic device (e.g., an emission apparatus) may further include, in addition to the light-emitting device 10, i) a color filter, ii) a color-conversion layer, or iii) a color filter and a color-conversion layer. The color filter and/or the color-conversion layer may be disposed in at least one direction in which light emitted from the light-emitting device 10 travels. For example, light emitted from the light-emitting device 10 may be blue light or white light. The light-emitting device 10 may be understood by referring to the descriptions provided herein. In an embodiment, the color conversion layer may include a quantum dot. The quantum dot may be, for example, a quantum dot as described herein.
The electronic device may include a first substrate. The first substrate may include a plurality of subpixel areas, the color filter may include a plurality of color filter areas respectively corresponding to the subpixel areas, and the color conversion layer may include a plurality of color conversion areas respectively corresponding to the subpixel areas.
A pixel-defining film may be located among the subpixel areas to define each of the subpixel areas.
The color filter may further include a plurality of color filter areas and light-shielding patterns located among the color filter areas, and the color conversion layer may further include a plurality of color conversion areas and light-shielding patterns located among the color conversion areas.
The plurality of color filter areas (or the plurality of color conversion areas) may include a first area emitting first color light, a second area emitting second color light, and/or a third area emitting third color light, wherein the first color light, the second color light, and/or the third color light may have different maximum emission wavelengths from one another. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light. For example, the plurality of color filter areas (or the plurality of color conversion areas) may include quantum dots. In particular, the first area may include a red quantum dot, the second area may include a green quantum dot, and the third area may not include a quantum dot. For details on the quantum dot, related descriptions provided herein may be referred to. The first area, the second area, and/or the third area may each include a scatterer.
In an embodiment, the light-emitting device 10 may emit first light, the first area may absorb the first light to emit 1-1 color light, the second area may absorb the first light to emit 2-1 color light, and the third area may absorb the first light to emit 3-1 color light. In this regard, the first-first color light, the second-first color light, and the third-first color light may have different maximum emission wavelengths. In particular, the first light may be blue light, the first-first color light may be red light, the second-first color light may be green light, and the third-first color light may be blue light.
The electronic device may further include a thin-film transistor, in addition to the light-emitting device 10. The thin-film transistor may include a source electrode, a drain electrode, and an active layer, and any one of the source electrode and the drain electrode may be electrically connected to one of the first electrode 110 and the second electrode 190 of the organic light-emitting device 10.
The thin-film transistor may further include a gate electrode, a gate insulating film, or the like.
The activation layer may include crystalline silicon, amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like.
The electronic device may further include an encapsulation unit for sealing the light-emitting device 10. The encapsulation unit may be located between the color filter and/or the color-conversion layer and the light-emitting device 10. The sealing portion allows light from the light-emitting device 10 to be extracted to the outside, while simultaneously preventing ambient air and moisture from penetrating into the light-emitting device 10. The sealing portion may be a sealing substrate including a transparent glass substrate or a plastic substrate. The sealing portion may be a thin-film encapsulation layer including at least one layer of an organic layer and/or an inorganic layer. When the sealing portion is a thin film encapsulation layer, the electronic device may be flexible.
Various functional layers may be additionally located on the sealing portion, in addition to the color filter and/or the color conversion layer, according to the use of the electronic device. Examples of the functional layers may include a touch screen layer, a polarizing layer, and the like. The touch screen layer may be a pressure-sensitive touch screen layer, a capacitive touch screen layer, or an infrared touch screen layer. The authentication apparatus may be, for example, a biometric authentication apparatus that authenticates an individual by using biometric information of a living body (for example, fingertips, pupils, etc.).
The authentication apparatus may further include, in addition to the organic light-emitting device 10, a biometric information collector.
The electronic device may be applied to various displays, light sources, lighting, personal computers (for example, a mobile personal computer), mobile phones, digital cameras, electronic organizers, electronic dictionaries, electronic game machines, medical instruments (for example, electronic thermometers, sphygmomanometers, blood glucose meters, pulse measurement devices, pulse wave measurement devices, electrocardiogram displays, ultrasonic diagnostic devices, or endoscope displays), fish finders, various measuring instruments, meters (for example, meters for a vehicle, an aircraft, and a vessel), projectors, and the like.
The light-emitting apparatus of
The substrate 100 may be a flexible substrate, a glass substrate, or a metal substrate. A buffer layer 210 may be located on the substrate 100. The buffer layer 210 may prevent penetration of impurities through the substrate 100 and may provide a flat surface on the substrate 100.
A TFT may be located on the buffer layer 210. The TFT may include an activation layer 220, a gate electrode 240, a source electrode 260, and a drain electrode 270.
The activation layer 220 may include an inorganic semiconductor such as silicon or polysilicon, an organic semiconductor, or an oxide semiconductor, and may include a source region, a drain region, and a channel region.
A gate insulating film 230 for insulating the activation layer 220 from the gate electrode 240 may be located on the activation layer 220, and the gate electrode 240 may be located on the gate insulating film 230.
An interlayer insulating film 250 may be located on the gate electrode 240. The interlayer insulating film 250 may be located between the gate electrode 240 and the source electrode 260 and between the gate electrode 240 and the drain electrode 270, to insulate from one another.
The source electrode 260 and the drain electrode 270 may be located on the interlayer insulating film 250. The interlayer insulating film 250 and the gate insulating film 230 may be formed to expose the source region and the drain region of the activation layer 220, and the source electrode 260 and the drain electrode 270 may be located in contact with the exposed portions of the source region and the drain region of the activation layer 220.
The TFT is electrically connected to a light-emitting device to drive the light-emitting device, and is covered and protected by a passivation layer 280. The passivation layer 280 may include an inorganic insulating film, an organic insulating film, or a combination thereof. A light-emitting device is provided on the passivation layer 280. The light-emitting device may include a first electrode 110, an interlayer 130, and a second electrode 150.
The first electrode 110 may be located on the passivation layer 280. The passivation layer 280 may be located to expose a portion of the drain electrode 270, not fully covering the drain electrode 270, and the first electrode 110 may be located to be connected to the exposed portion of the drain electrode 270.
A pixel defining layer 290 including an insulating material may be located on the first electrode 110. The pixel defining layer 290 may expose a certain region of the first electrode 110, and an interlayer 130 may be formed in the exposed region of the first electrode 110. The pixel defining layer 290 may be a polyimide or polyacrylic organic film. Although not shown in
The second electrode 150 may be located on the interlayer 130, and a capping layer 170 may be additionally formed on the second electrode 150. The capping layer 170 may be formed to cover the second electrode 150.
The encapsulation portion 300 may be located on the capping layer 170. The encapsulation portion 300 may be located on a light-emitting device to protect the light-emitting device from moisture or oxygen. The encapsulation portion 300 may include: an inorganic film including silicon nitride (SiNx), silicon oxide (SiOx), indium tin oxide, indium zinc oxide, or a combination thereof; an organic film including polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, hexamethyldisiloxane, an acrylic resin (for example, polymethyl methacrylate, polyacrylic acid, or the like), an epoxy-based resin (for example, aliphatic glycidyl ether (AGE), or the like), or a combination thereof; or a combination of the inorganic films and the organic films.
The light-emitting apparatus of
Respective layers included in the hole transport region, the emission layer, and respective layers included in the electron transport region may be formed in a certain region by using vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, laser-induced thermal imaging, or a combination thereof.
When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10−8 torr to about 10−3 torr, and a deposition speed of about 0.01 angstrom per second (Å/sec) to about 100 Å/sec, depending on a material to be included in a layer to be formed and the structure of a layer to be formed.
The term “C3-C60 carbocyclic group” as used herein refers to a cyclic group consisting of carbon only as a ring-forming atom and having three to sixty carbon atoms, and the term “C1-C60 heterocyclic group” as used herein refers to a cyclic group that has one to sixty carbon atoms and further has, in addition to carbon, a heteroatom as a ring-forming atom. The C3-C60 carbocyclic group and the C1-C60 heterocyclic group may each be a monocyclic group consisting of one ring or a polycyclic group in which two or more rings are condensed with each other. For example, the C1-C60 heterocyclic group has 3 to 61 ring-forming atoms.
The “cyclic group” as used herein may include the C3-C60 carbocyclic group, and the C1-C60 heterocyclic group.
The term “π electron-rich C3-C60 cyclic group” as used herein refers to a cyclic group that has three to sixty carbon atoms and does not include *—N═*′ as a ring-forming moiety, and the term “π electron-deficient nitrogen-containing C1-C60 cyclic group” as used herein refers to a heterocyclic group that has one to sixty carbon atoms and includes *—N═*′ as a ring-forming moiety.
For example, the C3-C60 carbocyclic group may be i) group T1 or ii) a condensed cyclic group in which two or more groups T1 are condensed with each other (for example, a cyclopentadiene group, an adamantane group, a norbornane group, a benzene group, a pentalene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a perylene group, a pentaphene group, a heptalene group, a naphthacene group, a picene group, a hexacene group, a pentacene group, a rubicene group, a coronene group, an ovalene group, an indene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, an indenophenanthrene group, or an indenoanthracene group),
the C1-C60 heterocyclic group may be i) group T2, ii) a condensed cyclic group in which two or more groups T2 are condensed with each other, or iii) a condensed cyclic group in which at least one group T2 and at least one group T1 are condensed with each other (for example, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, etc.),
the π electron-rich C3-C60 cyclic group may be i) group T1, ii) a condensed cyclic group in which two or more groups T1 are condensed with each other, iii) group T3, iv) a condensed cyclic group in which two or more groups T3 are condensed with each other, or v) a condensed cyclic group in which at least one group T3 and at least one group T1 are condensed with each other (for example, the C3-C60 carbocyclic group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, etc.),
the π electron-deficient nitrogen-containing C1-C60 cyclic group may be i) group T4, ii) a condensed cyclic group in which two or more groups T4 are condensed with each other, iii) a condensed cyclic group in which at least one group T4 and at least one group T1 are condensed with each other, iv) a condensed cyclic group in which at least one group T4 and at least one group T3 are condensed with each other, or v) a condensed cyclic group in which at least one group T4, at least one group T1, and at least one group T3 are condensed with one another (for example, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, etc.),
group T1 may be a cyclopropane group, a cyclobutane group, a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclooctane group, a cyclobutene group, a cyclopentene group, a cyclopentadiene group, a cyclohexene group, a cyclohexadiene group, a cycloheptene group, an adamantane group, a norbornane (or a bicyclo[2.2.1] heptane) group, a norbornene group, a bicyclo[1.1.1] pentane group, a bicyclo[2.1.1] hexane group, a bicyclo[2.2.2] octane group, or a benzene group, group T2 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a tetrazine group, a pyrrolidine group, an imidazolidine group, a dihydropyrrole group, a piperidine group, a tetrahydropyridine group, a dihydropyridine group, a hexahydropyrimidine group, a tetrahydropyrimidine group, a dihydropyrimidine group, a piperazine group, a tetrahydropyrazine group, a dihydropyrazine group, a tetrahydropyridazine group, or a dihydropyridazine group, group T3 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, or a borole group, and
group T4 may be a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group.
The terms “the cyclic group, the C3-C60 carbocyclic group, the C1-C60 heterocyclic group, the π electron-rich C3-C60 cyclic group, or the IT electron-deficient nitrogen-containing C1-C60 cyclic group” as used herein refer to a group condensed to any cyclic group, a monovalent group, or a polyvalent group (for example, a divalent group, a trivalent group, a tetravalent group, etc.) according to the structure of a formula for which the corresponding term is used. In an embodiment, “a benzene group” may be a benzo group, a phenyl group, a phenylene group, or the like, which may be easily understand by one of ordinary skill in the art according to the structure of a formula including the “benzene group.”
Examples of the monovalent C3-C60 carbocyclic group and the monovalent C1-C60 heterocyclic group may include a C3-C10 cycloalkyl group, a C1-C10 heterocycloalkyl group, a C3-C10 cycloalkenyl group, a C1-C10 heterocycloalkenyl group, a C6-C60 aryl group, a C1-C60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group. Examples of the divalent C3-C60 carbocyclic group and the divalent C1-C60 heterocyclic group may include a C3-C10 cycloalkylene group, a C1-C10 heterocycloalkylene group, a C3-C10 cycloalkenylene group, a C1-C10 heterocycloalkenylene group, a C6-C60 arylene group, a C1-C60 heteroarylene group, a divalent non-aromatic condensed polycyclic group, and a divalent non-aromatic condensed heteropolycyclic group.
The term “C1-C60 alkyl group” as used herein refers to a linear or branched aliphatic hydrocarbon monovalent group that has one to sixty carbon atoms, and specific examples thereof are a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, and a tert-decyl group. The term “C1-C60 alkylene group” as used herein refers to a divalent group having the same structure as the C1-C60 alkyl group.
The term “C2-C60 alkenyl group” as used herein refers to a monovalent hydrocarbon group having at least one carbon-carbon double bond in the middle or at the terminus of the C2-C60 alkyl group, and examples thereof are an ethenyl group, a propenyl group, and a butenyl group. The term “C2-C60 alkenylene group” as used herein refers to a divalent group having the same structure as the C2-C60 alkenyl group.
The term “C2-C60 alkynyl group” as used herein refers to a monovalent hydrocarbon group having at least one carbon-carbon triple bond in the middle or at the terminus of the C2-C60 alkyl group, and examples thereof include an ethynyl group, a propynyl group, and the like. The term “C2-C60 alkynylene group” as used herein refers to a divalent group having the same structure as the C2-C60 alkynyl group.
The term “C1-C60 alkoxy group” as used herein refers to a monovalent group represented by —OA101 (wherein A101 is the C1-C60 alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.
The term “C3-C10 cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group including 3 to 10 carbon atoms. Examples of the C3-C10 cycloalkyl group as used herein include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantyl group, a norbornyl (bicyclo[2.2.1] heptyl) group, a bicyclo[1.1.1] pentyl group, a bicyclo[2.1.1] hexyl group, or a bicyclo[2.2.2] octyl group. The term “C3-C10 cycloalkylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkyl group.
The term “C1-C10 heterocycloalkyl group” as used herein refers to a monovalent cyclic group of 1 to 10 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms, and specific examples are a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C1-C10 heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C1-C10 heterocycloalkyl group.
The term C3-C10 cycloalkenyl group used herein refers to a monovalent cyclic group that has three to ten carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and specific examples thereof are a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C3-C10 cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkenyl group.
The term “C1-C10 heterocycloalkenyl group” as used herein refers to a monovalent cyclic group of 1 to 10 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms, and having at least one carbon-carbon double bond in the cyclic structure thereof. Examples of the C1-C10 heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C1-C10 heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C1-C10 heterocycloalkenyl group.
The term “C6-C60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system of 6 to 60 carbon atoms, and the term “C6-C60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system of 6 to 60 carbon atoms. Examples of the C6-C60 aryl group are a phenyl group, a pentalenyl group, a naphthyl group, an azulenyl group, an indacenyl group, an acenaphthyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a heptalenyl group, a naphthacenyl group, a picenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, and an ovalenyl group. When the C6-C60 aryl group and the C6-C60 arylene group each include two or more rings, the rings may be condensed with each other.
The term “C1-C60 heteroaryl group” as used herein refers to a monovalent group having a heterocyclic aromatic system of 1 to 60 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms. The term “C1-C60 heteroarylene group” as used herein refers to a divalent group having a heterocyclic aromatic system of 1 to 60 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms. Examples of the C1-C60 heteroaryl group are a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, a benzoquinolinyl group, an isoquinolinyl group, a benzoisoquinolinyl group, a quinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl group, a phenanthrolinyl group, a phthalazinyl group, and a naphthyridinyl group. When the C1-C60 heteroaryl group and the C1-C60 heteroarylene group each include two or more rings, the rings may be condensed with each other.
The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group having two or more rings condensed and only carbon atoms (for example, having 8 to 60 carbon atoms) as ring-forming atoms, wherein the molecular structure as a whole is non-aromatic. Examples of the monovalent non-aromatic condensed polycyclic group are an indenyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, an indenophenanthrenyl group, and an indeno anthracenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group described above.
The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group having two or more rings condensed and carbon atoms (for example, having 1 to 60 carbon atoms) and at least one heteroatom as ring-forming atoms, wherein the molecular structure as a whole is non-aromatic. Examples of the monovalent non-aromatic condensed heteropolycyclic group include a 9,9-dihydroacridinyl group, and a 9H-xanthenyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group described above.
The term “C6-C60 aryloxy group” as used herein indicates —OA102 (wherein A102 is a C6-C60 aryl group), and the term “C6-C60 arylthio group” as used herein indicates —SA103 (wherein A103 is a C6-C60 aryl group).
The term “C7-C60 arylalkyl group” used herein refers to —A104A105 (where A104 may be a C1-C54 alkylene group, and A105 may be a C6-C59 aryl group), and the term C2-C60 heteroarylalkyl group” used herein refers to —A106A107 (where A106 may be a C1-C59 alkylene group, and A107 may be a C1-C59 heteroaryl group).
The term “R10a” as used herein refers to:
deuterium, —F, —CI, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, or a C1-C60 alkoxy group, each unsubstituted or substituted with deuterium, —F, —CI, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q11)(Q12)(Q13), —N(Q11)(Q12), —B(Q11)(Q12), —C(═O)(Q11), —S(═O)2(Q11), —P(═O)(Q11)(Q12), or a combination thereof;
a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, or a C2-C60 heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q21) (Q22)(Q23), —N(Q21)(Q22), —B(Q21)(Q22), —C(═O)(Q21), —S(═O)2(Q21), —P(═O)(Q21)(Q22), or a combination thereof; or
—Si(Q31)(Q32)(Q33), —N(Q31)(Q32), —B(Q31)(Q32), —C(═O)(Q31), —S(═O)2(Q31), or —P(═O)(Q31)(Q32).
Q1 to Q3, Q11 to Q13, Q21 to Q23 and Q31 to Q33 used herein may each independently be: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C1-C60 alkyl group; a C2-C60 alkenyl group; a C2-C60 alkynyl group; a C1-C60 alkoxy group; a C3-C60 carbocyclic group or a C1-C60 heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C1-C60 alkyl group, a C1-C60 alkoxy group, a phenyl group, a biphenyl group, or any combination thereof; a C7-C60 arylalkyl group; or a C2-C60 heteroarylalkyl group.
The term “heteroatom” as used herein refers to any atom other than a carbon atom. Examples of the heteroatom are O, S, N, P, Si, B, Ge, Se, or a combinations thereof.
The term “third-row transition metal” used herein includes hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and the like.
The term “Ph” as used herein refers to a phenyl group, the term “Me” as used herein refers to a methyl group, the term “Et” as used herein refers to an ethyl group, the term “ter-Bu” or “But” as used herein refers to a tert-butyl group, and the term “OMe” as used herein refers to a methoxy group.
The term “biphenyl group” as used herein refers to “a phenyl group substituted with a phenyl group.” In other words, the “biphenyl group” is a substituted phenyl group having a C6-C60 aryl group as a substituent.
The term “terphenyl group” as used herein refers to “a phenyl group substituted with a biphenyl group”. In other words, the “terphenyl group” is a substituted phenyl group having, as a substituent, a C6-C60 aryl group substituted with a C6-C60 aryl group.
* and *′ as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula or moiety.
Hereinafter, a composition and a light-emitting device according to an embodiment will be described in detail with reference to the following Examples.
Mixed compositions were prepared by mixing respective compounds according to a content ratio thereof shown in Table 1.
Ultrasonic cleaning was sequentially performed on a Si wafer (10 millimeters (mm)×10 mm) using distilled water and isopropanol. By spin-coating the composition according to Table 2 on the Si wafer and forming a film having a thickness of 100 nm, Film A or B was formed.
With respect to the films prepared according to Preparation Example 2, scanning electron microscopy (SEM) images were measured under the condition of 15 kilovolts (kV) using EOL-7800F, which are shown in
From
In addition, from
An indium tin oxide (ITO) glass substrate (50 millimeters (mm)×50 mm and 15 ohms per square centimeter (Ω/cm2)), which is an organic light-emitting diode (OLED) glass (available from Samsung-Corning) substrate, was sequentially sonicated using distilled water and isopropyl alcohol, and cleaned by exposure to ultraviolet rays with ozone for about 30 minutes. Composition 4 was spin-coated on the ITO glass substrate to form a film having a thickness of 40 nm, followed by baking at 100° C. for 30 minutes, thereby forming a metal oxide layer. A ZnSeTe quantum dot composition (solvent: octane, solid concentration: ZnSeTe 0.7 wt %) was spin-coated on the metal oxide layer to form a film having a thickness of 30 nm, followed by baking at 120° C. for 10 minutes, thereby forming an emission layer. Composition 1 was spin-coated on the emission layer to form a film to a thickness of 40 nm, followed by baking at a temperature of 100° C. for 30 minutes, thereby forming an electron transport layer. Al was deposited on the electron transport layer to a thickness of 100 nm to form a cathode, thereby completing the manufacture of an electron only device (EOD). Then, heat-treating was further performed thereon at a temperature of 75° C. for 24 hours. The equipment used for the deposition was a Suicel plus 200 evaporator from Sunic Systems.
EODs were manufactured in the same manner as in Example 1, except that the mixed composition of the electron transport layer was changed (according to the content of the metal oxide and the metal halogen as in Table 1) as shown in Table 3.
The driving voltage of each of EODs manufactured in Examples 1 to 3 and Comparative Example 1 was measured at a current density of 10 milliamperes per square centimeter (mA/cm2) by using a current-voltmeter (Kethley SMU 236). The results thereof are shown in Table 4.
As shown in Table 4, the light-emitting devices of Examples 1 to 3 were found to have improved driving voltages, as compared with the light-emitting device of
Preparation Example 3: Preparation of First Composition and Second Composition
A first composition was prepared by mixing compounds according to the content ratio indicated in Table 5, and a second composition was prepared by mixing compound according to the content ratio indicated in Table 6.
An ITO glass substrate (50 mm×50 mm and 15 Ω/cm2), which is an OLED glass (available from Samsung-Corning) substrate, was sequentially sonicated using distilled water and isopropyl alcohol, and cleaned by exposure to ultraviolet rays with ozone for about 30 minutes. Composition 4 was spin-coated on the ITO glass substrate to form a film having a thickness of 40 nm, followed by baking at 100° C. for 30 minutes, thereby forming a metal oxide layer. A ZnSeTe quantum dot composition (solvent: octane, solid concentration of ZnSeTe (0.7 wt %)) was spin-coated on the metal oxide layer to form a film having a thickness of 30 nm, followed by baking at 120° C. for 10 minutes, thereby forming an emission layer. Composition 1-1 was spin-coated on the emission layer to form a film to a thickness of 40 nm, followed by baking at a temperature of 100° C. for 30 minutes. After applying Composition 2-1 on Composition 1-1 and waiting for 60 seconds, the residual solvent was removed to form an electron transport layer.
Al was deposited on the electron transport layer to a thickness of 100 nm to form a cathode, thereby completing the manufacture of an EOD. Then, heat-treating was further performed thereon at a temperature of 75° C. for 24 hours. The equipment used for the deposition was a Suicel plus 200 evaporator from Sunic Systems.
EODs were manufactured in the same manner as in Example 4, except that the mixed composition and/or time for the 75° C. heat-treating were changed as shown in Table 7.
The driving voltage of each of EODs manufactured in Examples 4 to 7 and Comparative Examples 2 and 3 was measured at a current density of 10 milliamperes per square centimeter (mA/cm2) by using a current-voltmeter (Kethley SMU 236). The results thereof are shown in Table 8.
As shown in Table 8, the EODs of Examples 4 to 7 were found to have improved driving voltages, as compared with the EODs of Comparative Examples 2 and 3.
A mixed composition according to an embodiment may reduce oxygen vacancy of a surface of a metal oxide, suppress exciton quenching generated in an emission layer, and minimize hole leaking current, which leads to improved emission efficiency and lifespan.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0169101 | Dec 2022 | KR | national |
