Patent Application
20220255011
This application is claims priority from and the benefit of Korean Patent Application No. 10-2021-0012649, filed on Jan. 28, 2021, which is hereby incorporated by reference for all purposes as if fully set forth herein.
Embodiments of the invention relate generally to display devices and, more particularly, to a light-emitting device and an electronic apparatus including the same.
Light-emitting devices are self-emissive devices that have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of luminance, driving voltage, and response speed, and produce full-color images.
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 formed on the first electrode. Holes injected from the first electrode move to the emission layer through a non-luminescent exciton transport region that does not contribute to light emission among excitons generated inside the emission layer, and electrons injected from the second electrode move to the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state to thereby generate light.
The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.
Light-emitting devices constructed according to principles and illustrative implementations of the invention exhibit driving voltage, efficiency, and lifespan equivalent to those of light-emitting devices of the related art, while reducing production costs by simplifying manufacture by omission of a p-doping layer, and having improved color purity and color accuracy while minimizing or preventing the occurrence of mixing of colors due to leakage current. In addition, the application of an Al-based anode may prevent a decrease in the efficiency of the light-emitting devices.
Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.
According to one aspect of the invention, a light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, a hole transport region between the first electrode and the emission layer, and an electron transport region between the emission layer and the second electrode, wherein the hole transport region includes a hole injection layer and a hole transport layer, sequentially arranged between the first electrode and the emission layer, the first electrode includes aluminum, an alloy including aluminum, or any combination thereof, the hole injection layer consists of a first inorganic material including In2O3, GeO2, SnO2, MoOx, WOx, CoOy, CuOy, NiOy, or any combination thereof (wherein 2.5≤x≤3.0, 0.5≤y≤2.0), an absolute value of a work function of the first inorganic material is greater than or equal to an absolute value of a HOMO energy level of the hole transport layer, and the hole transport region excludes a p-dopant.
The first electrode may consist of aluminum, an alloy including aluminum, or any combination thereof.
The first electrode may include AlNiLa, AlNd, AlNiGeLa, AlCoGeLa, or any combination thereof.
The absolute value of the work function of the first inorganic material may be about 5.15 eV or more.
The first inorganic material may include: In2O3; WO3; a mixture of In2O3, GeO2, and SnO2; a mixture in which at least one of SnO2, MoO3, and WO3 may be doped with In2O3 at a concentration of about 5 wt % or less; or any combination thereof.
The first electrode and the hole injection layer may be collectively dry-etched.
The absolute value of the HOMO energy level of the hole transport layer may be about 5.15 eV or less.
The hole transport region may include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof:
wherein, in Formulae 201 and 202, the variables are defined herein.
The hole transport region may further include an electron blocking layer between the hole transport layer and the emission layer.
The absolute value of a HOMO energy level of the electron blocking layer may be greater than or equal to an absolute value of a HOMO energy level of the emission layer, and less than or equal to the absolute value of the HOMO energy level of the hole 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 any combination thereof.
The electron transport region may include a hole blocking layer, an electron transport layer, and an electron injection layer, sequentially arranged between the emission layer and the second electrode.
The absolute value of a HOMO energy level of the hole blocking layer may be less than or equal to an absolute value of a HOMO energy level of the emission layer, and less than or equal to an absolute value of a HOMO energy level of the electron transport layer.
The emission layer may include a host and a dopant, and the dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof, the emission layer may include one or more quantum dots, or the emission layer may include a delayed fluorescence material, and the delayed fluorescence material functions as a host or a dopant in the emission layer.
The first electrode may be an anode, and the second electrode may be a cathode.
The light-emitting device may further include at least one of: a first capping layer located outside the first electrode; and a second capping layer located outside the second electrode, and the first capping layer and the second capping layer may each include a material having a refractive index of about 1.6 or more at a wavelength of 589 nm.
The interlayer may include two or more light-emitting units sequentially stacked between the first electrode and the second electrode and at least one charge generation layer between the two or more light-emitting units.
An electronic apparatus may include the light-emitting device as described above.
The electronic apparatus may further include a thin-film transistor, wherein the thin-film transistor may include a source electrode and a drain electrode, and the first electrode of the light-emitting device may be electrically connected to at least one of the source electrode and the drain electrode of the thin-film transistor.
The electronic apparatus may further include a color filter, a color conversion layer, a touch screen layer, a polarizing layer, or any combination thereof.
It is to be understood that both the foregoing general description and the following detailed description are illustrative and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate illustrative embodiments of the invention, and together with the description serve to explain the inventive concepts.
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments or implementations of the invention. As used herein “embodiments” and “implementations” are interchangeable words that are non-limiting examples of devices or methods employing one or more of the inventive concepts disclosed herein. It is apparent, however, that various embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring various embodiments. Further, various embodiments may be different, but do not have to be exclusive. For example, specific shapes, configurations, and characteristics of an embodiment may be used or implemented in another embodiment without departing from the inventive concepts.
Unless otherwise specified, the illustrated embodiments are to be understood as providing illustrative features of varying detail of some ways in which the inventive concepts may be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions, plates and/or aspects, etc. (hereinafter individually or collectively referred to as “elements”), of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.
The use of cross-hatching and/or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and/or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. When an embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. Also, like reference numerals denote like elements, and those components that are the same or are in correspondence with each other are rendered the same reference numeral regardless of the figure number, and redundant explanations are omitted.
When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. When, however, an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. To this end, the term “connected” may refer to physical, electrical, and/or fluid connection, with or without intervening elements. Further, the D1-axis, the D2-axis, and the D3-axis are not limited to three axes of a rectangular coordinate system, such as the x, y, and z-axes, and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another. For the purposes of this disclosure, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be construed as X only, Y only, Z only, or any combination of two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms “first,” “second,” etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.
Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one elements relationship to another element(s) as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and/or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Moreover, the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.
Various embodiments are described herein with reference to sectional and/or exploded illustrations that are schematic illustrations of idealized embodiments and/or intermediate structures. 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 disclosed herein should not necessarily be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. In this manner, regions illustrated in the drawings may be schematic in nature and the shapes of these regions may not reflect actual shapes of regions of a device and, as such, are not necessarily intended to be limiting.
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 is a part. 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 should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.
A highest occupied molecular orbital (HOMO) energy level and a work function as used herein may be the same as described below, but embodiments are not limited thereto.
The light-emitting device 10 may include a first electrode 110, an interlayer 130, and a second electrode 150. Hereinafter, the structure of the light-emitting device 10 according to an embodiment and an illustrative method of manufacturing the light-emitting device 10 will be described in connection with
Referring to
In the related art, since the work function of ITO (work function of about 4.8 eV) mainly used as an anode is not high, for injection of holes, a p-doped hole injection layer is introduced between the anode and a hole transport layer. However, due to the introduction of such a hole injection layer, a leakage current in a lateral direction occurs. In the light-emitting device 10, the occurrence of a leakage current in a lateral direction due to a p-dopant or the like may be inhibited by not including the p-dopant in the hole transport region 131. Furthermore, mixing of colors due to the occurrence of the leakage current may also be prevented. In addition, when the existing p-dopant-doped hole injection layer is included, the hole injection characteristics change according to the temperature of the hole injection layer, so that the operation lifespan is poor at high temperature.
An anode in the related art has a triple-layered structure of ITO/Ag/ITO. In this case, when a light-emitting device has two or more tandem structures, although not wanting to be bound by theory, a loss in efficiency of the light-emitting device occurs due to surface plasmon polariton (SPP), and a silver particle dark spot occurs due to re-deposition of silver (Ag). However, in the light-emitting device 10, aluminum or an aluminum alloy is introduced as an anode, and thus, the occurrence of a dark spot due to Ag as in the related art may be minimized or prevented, thereby reducing the loss in efficiency of a light-emitting device described above.
In addition, because the hole injection layer 131a consists of the first inorganic material including In2O3, GeO2, SnO2, MoOx, WOx, CoOy, CuOy, NiOy, or any combination thereof, and the work function of the first inorganic material and the HOMO energy level of the hole transport layer 131b satisfy the above described relationship, holes may be efficiently injected without an energy barrier, and driving voltage characteristics may be improved.
In an embodiment, the first electrode 110 may consist of aluminum (Al), an Al-based alloy, or any combination thereof. In an embodiment, the first electrode 110 may include AlNiLa, AlNd, AlNiGeLa, AlCoGeLa, or any combination thereof. For example, the first electrode 110 may consist of an Al-based alloy. In an embodiment, the first electrode 110 may have a single-layered structure consisting of a single layer. In an embodiment, the absolute value of the work function of the first inorganic material may be about 5.15 eV or more. For example, the absolute value of the work function of the first inorganic material may be about 5.20 eV or more. For example, the absolute value of the work function of the first inorganic material may be about 5.30 eV or more.
As described above, because the first inorganic material included in the hole injection layer 131a satisfies the above described work function range, holes may be efficiently injected even when the hole transport layer 131b having a deep HOMO energy level is applied, and lifespan characteristics of the light-emitting device 10 may be improved according to the deep HOMO energy level of the hole transport layer 131b. In an embodiment, the first inorganic material may include: In2O3; WO3; a mixture of In2O3, GeO2, and SnO2; a mixture in which at least one selected from SnO2, MoO3, and WO3 is doped in In2O3 at a concentration of about 5 weight percent (wt %) or less; or any combination thereof. In an embodiment, the first electrode 110 and the hole injection layer 131a may be collectively dry-etched.
An Ag-containing anode of the related art performs wet etching, whereas an anode including an Al-based material as disclosed herein may perform dry etching. Accordingly, a hole injection layer and an anode may be collectively dry-etched, thereby ensuring excellent processability. In an embodiment, the hole injection layer 131a and the hole transport layer 131b may ohmic contact each other. In an embodiment, the first electrode 110 and the hole injection layer 131a may directly contact each other. In an embodiment, the hole injection layer 131a and the hole transport layer 131b may directly contact each other.
In an embodiment, the absolute value of the HOMO energy level of the hole transport layer 131b may be about 5.15 eV or less. For example, the absolute value of the HOMO energy level of the hole transport layer 131b may be in a range of about 5.10 eV to about 5.15 eV. In an embodiment, the hole transport layer 131b may include a metal oxide.
For example, the metal oxide may be WO3, MoO3, ZnO, Cu2O, CuO, CoO, Ga2O3, GeO2, or any combination thereof, and the metal oxide may be different from the first inorganic material. In an embodiment, the hole transport region 131 may further include an electron blocking layer 131c between the hole transport layer 131b and the emission layer 132.
For example, the absolute value of a HOMO energy level of the electron blocking layer 131c may be greater than or equal to the absolute value of a HOMO energy level of the emission layer 132, and less than or equal to the absolute value of the HOMO energy level of the hole transport layer 131b. In an embodiment, the electron transport region 133 may include a buffer layer, a hole blocking layer 133a, an electron control layer, an electron transport layer 133b, an electron injection layer, or any combination thereof.
For example, the electron transport region 133 may include a hole blocking layer 133a, an electron transport layer 133b, and an electron injection layer, sequentially arranged between the emission layer 132 and the second electrode 150. For example, the absolute value of a HOMO energy level of the hole blocking layer 133a may be less than or equal to the absolute value of the HOMO energy level of the emission layer 132, and less than or equal to the absolute value of a HOMO energy level of the electron transport layer 133b.
In an embodiment, the emission layer 132 may include a host and a dopant, and the dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof, the emission layer 132 may include quantum dots, or the emission layer 132 may include a delayed fluorescence material, and the delayed fluorescence material may function as a host or a dopant in the emission layer 132. In an embodiment, the first electrode 110 may be an anode, and the second electrode 150 may be a cathode. As described above, the light-emitting device 10 does not include the anode and the hole transport region of the related art, and thus may have a simplified structure and process, thereby reducing process costs and preventing a decrease in device efficiency.
According to another aspect, an electronic apparatus including the light-emitting device may further include a thin-film transistor. In an embodiment, the electronic apparatus may further include a thin-film transistor including a source electrode and a drain electrode, and the first electrode of the light-emitting device may be electrically connected to the source electrode or the drain electrode. In one or more embodiments, the electronic apparatus may further include a color filter, a color conversion layer, a touch screen layer, a polarizing layer, or any combination thereof. More details on the electronic apparatus are the same as described herein. Specific components, such as the first electrode 110 and interlayer 130, are discussed in more detail below.
In
The interlayer 130 may be located on the first electrode 110. The interlayer 130 may include an emission layer 132. The interlayer 130 may further include a hole transport region 131 located between the first electrode 110 and the emission layer 132 and an electron transport region 133 located between the emission layer 132 and the second electrode 150. The interlayer 130 may further include, in addition to various organic materials, metal-containing compounds such as organometallic compounds, inorganic materials such as quantum dots, and the like.
In one or more embodiments, 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) at least one charge generation layer located between the two emitting units. When the interlayer 130 includes the emitting unit and the charge generation layer as described above, the light-emitting device 10 may be a tandem light-emitting diode.
The hole transport region 131 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 131 may include a hole injection layer 131a, a hole transport layer 131b, an emission auxiliary layer, an electron blocking layer 131c, or any combination thereof.
In an embodiment, the hole transport region 131 may have a multi-layered structure having a hole injection layer 131a/hole transport layer 131b structure, a hole injection layer 131a/hole transport layer 131b/emission auxiliary layer structure, a hole injection layer 131a/emission auxiliary layer structure, a hole transport layer 131b/emission auxiliary layer structure, or a hole injection layer 131a/hole transport layer 131b/electron blocking layer 131c structure, wherein for each structure, constituting layers are sequentially stacked from the first electrode 110 in this stated order.
The hole transport region 131 may include a compound represented by Formula 201, a compound represented by Formula 202, or any 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 selected from 0 to 5,
xa5 may be an integer selected from 1 to 10,
R201 to R204 and Q201 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,
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 or the like) 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 selected from 1 to 4.
In an embodiment, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY217:
The variables R10b and R10c, in Formulae CY201 to CY217 are the same as described in connection with 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.
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 one or more embodiments, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY203. In one or more embodiments, Formula 201 may include at least one of groups represented by Formulae CY201 to CY203 and at least one of groups represented by Formulae CY204 to CY217.
In one or more embodiments, xa1 in Formula 201 is 1, R201 is 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 one or more embodiments, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY203. In one or more embodiments, 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 groups represented by Formulae CY204 to CY217. In one or more embodiments, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY217.
In one or more embodiments, the hole transport region 131 may include one of Compounds HT1 to HT46, 4,4′,4″-tris[phenyl(m-tolyl)amino]triphenylamine (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), bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (NPB or NPD), N4,N4′-di(naphthalen-2-yl)-N4,N4′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (β-NPB), N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD), N,N′-bis(3-methylphenyl)-N,N′-diphenyl-9,9-spirobifluorene-2,7-diamine (Spiro-TPD), N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9,9′-spirobi[9H-fluorene]-2,7-diamine (Spiro-NPB), N,N′-di(1-naphthyl)-N,N′-diphenyl-2,2′-dimethyl-(1,1′-biphenyl)-4,4′-diamine (methylated NPB), 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), N,N,N′,N′-tetrakis(3-methylphenyl)-3,3′-dimethylbenzidine (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 any combination thereof:
The thickness of the hole transport region 131 may be in a range of about 50 Å to about 10,000 Å, for example, about 100 Å to about 4,000 Å. When the hole transport region 131 includes a hole injection layer 131a, a hole transport layer 131b, or a combination thereof, the thickness of the hole injection layer 131a may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å, and the thickness of the hole transport layer 131b 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 131, the hole injection layer 131a, and the hole transport layer 131b 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 131c may block the leakage of electrons from the emission layer 132 to the hole transport region 131. Materials that may be included in the hole transport region 131 may be included in the emission auxiliary layer and the electron blocking layer 131c.
Emission layer 132 in interlayer 130
When the light-emitting device 10 is a full-color light-emitting device, the emission layer 132 may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to subpixel. In one or more embodiments, the emission layer 132 may have a stacked structure of two or more layers of a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers contact each other or are separated from each other. In one or more embodiments, the emission layer may include two or more materials of a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light. The emission layer 132 may include a host and a dopant. The dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof.
The amount of the dopant in the emission layer 132 may be from about 0.01 to about 15 parts by weight based on 100 parts by weight of the host. In one or more embodiments, the emission layer 132 may include one, two, ten, one-hundred or more quantum dots. The emission layer 132 may include a delayed fluorescence material. The delayed fluorescence material may function as a host or a dopant in the emission layer 132.
The thickness of the emission layer 132 may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer 132 is within these ranges, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.
The host may include a compound represented by Formula 301:
[Ar301]xb11-[(L301)xb1-R301]xb21 Formula 301
In Formula 301,
Ar301 and L301 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,
xb11 may be 1, 2, or 3,
xb1 may be an integer selected from 0 to 5,
R301 may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkenyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkynyl group unsubstituted or substituted with at least one R10a, a C1-C60 alkoxy group unsubstituted or substituted with at least one R10a, 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(Q301)(Q302)(Q303), —N(Q301)(Q302), —B(Q301)(Q302), —C(═O)(Q301), —S(═O)2(Q301), or —P(═O)(Q301)(Q302),
xb21 may be an integer selected from 1 to 5, and
Q301 to Q303 are the same as described in connection with Q1.
For example, when xb11 in Formula 301 is 2 or more, two or more of Ar301(s) may be linked to each other via a single bond.
In one or more embodiments, the host may include a compound represented by Formula 301-1, a compound represented by Formula 301-2, or any combination thereof:
In Formulae 301-1 and 301-2,
ring A301 to ring A304 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,
X301 may be O, S, N-[(L304)xb4-R304], C(R304)(R305), or Si(R304)(R305),
xb22 and xb23 may each independently be 0, 1, or 2,
L301, xb1, and R301 are the same as described herein,
L302 to L304 may each independently be the same as described in connection with L301,
xb2 to xb4 may each independently be the same as described in connection with xb1, and
R302 to R305 and R311 to R314 are the same as described in connection with R301.
In one or more embodiments, the host may include an alkali earth metal complex, a post-transition metal complex, or any combination thereof. In one or more embodiments, the host may include a Be complex (for example, Compound H55), an Mg complex, a Zn complex, or any combination thereof.
In an embodiment, the host may include one of Compounds H1 to H124, 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), or any combination thereof:
The phosphorescent dopant may include at least one transition metal as a central metal. The phosphorescent dopant may include a monodentate ligand, a bidentate ligand, a tridentate ligand, a tetradentate ligand, a pentadentate ligand, a hexadentate ligand, or any combination thereof. The phosphorescent dopant may be electrically neutral.
For example, the phosphorescent dopant may include an organometallic compound represented by Formula 401:
In Formulae 401 and 402,
M may be a transition metal (for example, iridium (Ir), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), gold (Au)hafnium (Hf), europium (Eu), terbium (Tb), rhodium (Rh), rhenium (Re), or thulium (Tm)),
L401 may be a ligand represented by Formula 402, and xc1 may be 1, 2, or 3, wherein when xc1 is two or more, two or more of L401(s) may be identical to or different from each other,
L402 may be an organic ligand, and xc2 may be 0, 1, 2, 3, or 4, and when xc2 is 2 or more, two or more of L402(s) may be identical to or different from each other,
X401 and X402 may each independently be nitrogen or carbon,
ring A401 and ring A402 may each independently be a C3-C60 carbocyclic group or a C1-C60 heterocyclic group,
T401 may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q411)-*′, *—C(Q411)(Q412)-*′, *—C(Q411)═C(Q412)-*′, *—C(Q411)=*′, or *═C═*′,
X403 and X4O4 may each independently be a chemical bond (for example, a covalent bond or a coordination bond), O, S, N(Q413), B(Q413), P(Q413), C(Q413)(Q414), or Si(Q413)(Q414),
Q411 to Q414 are the same as described in connection with Q1,
R401 and R402 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C20 alkyl group unsubstituted or substituted with at least one R10a, a C1-C20 alkoxy group unsubstituted or substituted with at least one R10a, 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(Q401)(Q402)(Q403), —N(Q401)(Q402), —B(Q401)(Q402), —C(═O)(Q401), —S(═O)2(Q401), or —P(═O)(Q401)(Q402),
Q401 to Q403 are the same as described in connection with Q1,
xc11 and xc12 may each independently be an integer selected from 0 to 10, and
* and *′ in Formula 402 each indicate a binding site to M in Formula 401.
For example, in Formula 402, i) X401 may be nitrogen, and X402 may be carbon, or ii) each of X401 and X402 may be nitrogen.
In one or more embodiments, when xc1 in Formula 402 is 2 or more, two ring A401 in two or more of L401(s) may be optionally linked to each other via T402, which is a linking group, and two ring A402 are optionally linked to each other via T403, which is a linking group (see Compounds PD1 to PD4 and PD7). The variables T402 and T403 are the same as described in connection with T401.
The variable L402 in Formula 401 may be an organic ligand. For example, L402 may include a halogen group, a diketone group (for example, an acetylacetonate group), a carboxylic acid group (for example, a picolinate group), a —C(═O) group, an isonitrile group, a —CN group, a phosphorus group (for example, a phosphine group, a phosphite group, etc.), or any combination thereof.
The phosphorescent dopant may include, for example, one of compounds PD1 to PD25, or any combination thereof.
The fluorescent dopant may include an amine group-containing compound, a styryl group-containing compound, or any combination thereof. In one or more embodiments, the fluorescent dopant may include a compound represented by Formula 501:
wherein, in Formula 501,
Ar501, L501 to L503, R501, and R502 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,
xd1 to xd3 may each independently be 0, 1, 2, or 3, and
xd4 may be 1, 2, 3, 4, 5, or 6.
In one or more embodiments, Ar501 in Formula 501 may be a condensed cyclic group (for example, an anthracene group, a chrysene group, or a pyrene group) in which three or more monocyclic groups are condensed together.
In one or more embodiments, xd4 in Formula 501 may be 2.
In one or more embodiments, the fluorescent dopant may include: one of Compounds FD1 to FD36; DPVBi; DPAVBi; or any combination thereof:
The emission layer 132 may include a delayed fluorescence material. As disclosed herein, the delayed fluorescence material may be selected from compounds capable of emitting delayed fluorescence based on a delayed fluorescence emission mechanism. The delayed fluorescence material included in the emission layer 132 may function as a host or a dopant depending on the type of other materials included in the emission layer 132.
In one or more embodiments, the difference between the triplet energy level (eV) of the delayed fluorescence material and the singlet energy level (eV) of the delayed fluorescence material may be greater than or equal to about 0 eV and less than or equal to about 0.5 eV. When the difference between the triplet energy level (eV) of the delayed fluorescence material and the singlet energy level (eV) of the delayed fluorescence material satisfies the above-described range, up-conversion from the triplet state to the singlet state of the delayed fluorescence materials may effectively occur, and thus, the luminescence efficiency of the light-emitting device 10 may be improved.
In one or more embodiments, the delayed fluorescence material may include i) a material including at least one electron donor (for example, a π electron-rich C3-C60 cyclic group, such as a carbazole group) and at least one electron acceptor (for example, a sulfoxide group, a cyano group, or a π electron-deficient nitrogen-containing C1-C60 cyclic group), and ii) a material including a C8-C60 polycyclic group in which two or more cyclic groups are condensed while sharing boron (B).
In one or more embodiments, the delayed fluorescence material may include at least one of the following compounds DF1 to DF9:
The emission layer 132 may include one two, ten, one-hundred or more quantum dots. As disclosed herein, a quantum dot refers to a crystal of a semiconductor compound, and may include any material capable of emitting light of various emission wavelengths according to the size of the crystal. The diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm. 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 process similar thereto.
According to the wet chemical process, a precursor material is mixed with an organic solvent to grow a quantum dot particle crystal. When the crystal grows, the organic solvent naturally functions 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 is more easily performed than vapor deposition methods, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), and which requires low costs.
The quantum dot may include semiconductor compounds of Groups II-VI, semiconductor compounds of Groups III-V, semiconductor compounds of Groups III-VI, semiconductor compounds of Groups I, III, and VI, semiconductor compounds of Groups IV-VI, an element or a compound of Group IV; or any combination thereof.
Examples of the semiconductor compound of Groups II-VI are a binary compound, such as 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 any combination thereof.
Examples of the semiconductor compound of Groups III-V are a binary compound, such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or the like; a ternary compound, such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, InPSb, or the like; a quaternary compound, such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or the like; or any combination thereof. The semiconductor compound of Groups III-V may further include Group II elements. Examples of the Groups III-V further including Group II elements are InZnP, InGaZnP, InAlZnP, etc.
Examples of the semiconductor compound of Groups III-VI are a binary compound, such as GaS, GaSe, Ga2Se3, GaTe, InS, InSe, In2S3, In2Se3, or InTe; a ternary compound, such as InGaS3, or InGaSe3; and any combination thereof. Examples of the semiconductor compound of Groups I, III, and VI are a ternary compound, such as AgInS, AgInS2, CuInS, CuInS2, CuGaO2, AgGaO2, or AgAlO2; or any combination thereof.
Examples of the semiconductor compound of Groups IV-VI are a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or the like; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or the like; a quaternary compound, such as SnPbSSe, SnPbSeTe, SnPbSTe, or the like; or any combination thereof. The element or compound of Group IV may include a single element compound, such as Si or Ge; a binary compound, such as SiC or SiGe; or any combination thereof.
Each element included in a multi-element compound such as the binary compound, ternary compound and quaternary compound, may exist in a particle with a uniform concentration or non-uniform concentration. The quantum dot may have a single structure or a dual core-shell structure. In the case of the quantum dot having the single structure, the concentration of each element included in the corresponding quantum dot is uniform. In one or more embodiments, the material contained in the core and the material contained in the shell may be different from each other.
The shell of the quantum dot may function as a protective layer to prevent chemical degeneration of the core to maintain semiconductor characteristics and/or as a charging layer to impart electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. The interface between the core and the shell may have a concentration gradient that decreases toward the center of the element present in the shell.
Examples of the shell of the quantum dot may be an oxide of a metal, a metalloid, or a non-metal, a semiconductor compound, and any combination thereof. Examples of the oxide of the 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; and any combination thereof. Examples of the semiconductor compound are, as described herein, semiconductor compounds of Groups II-VI; semiconductor compounds of Groups III-V; semiconductor compounds of Groups III-VI; semiconductor compounds of Groups I, III, and VI; semiconductor compounds of Groups IV-VI; and any combination thereof. In addition, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any combination thereof.
The full width at half maximum (FWHM) of an emission wavelength spectrum of the quantum dot may be about 45 nm or less, for example, about 40 nm or less, for example, about 30 nm or less, and within these ranges, color purity or color gamut may be increased. In addition, since the light emitted through the quantum dot is emitted in all directions, the wide viewing angle can be improved.
In addition, the quantum dot may be a generally spherical particle, a generally pyramidal particle, a generally multi-armed particle, a generally cubic nanoparticle, a generally nanotube-shaped particle, a generally nanowire-shaped particle, a generally nanofiber-shaped particle, or a generally nanoplate-shaped particle.
Because the energy band gap can be adjusted by controlling the size of the quantum dot, light having various wavelength bands can be obtained from the quantum dot emission layer. Therefore, by using quantum dots of different sizes, a light-emitting device that emits light of various wavelengths may be implemented. In one or more embodiments, 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 combining light of various colors.
The electron transport region 133 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 transport region 133 may include a buffer layer, a hole blocking layer 133a, an electron control layer, an electron transport layer 133b, an electron injection layer, or any combination thereof. In an embodiment, the electron transport region 133 may have an electron transport layer 133b/electron injection layer structure, a hole blocking layer 133a/electron transport layer 133b/electron injection layer structure, an electron control layer/electron transport layer 133b/electron injection layer structure, or a buffer layer/electron transport layer 133b/electron injection layer structure, wherein for each structure, constituting layers are sequentially stacked from an emission layer.
The electron transport region 133 (for example, the buffer layer, the hole blocking layer 133a, the electron control layer, or the electron transport layer 133b in the electron transport region 133) may include a metal-free compound including at least one R electron-deficient nitrogen-containing C1-C60 cyclic group.
In an embodiment, the electron transport region 133 may include a compound represented by Formula 601:
[Ar601]xe1-[(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 are the same as described in connection with 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 via a single bond. In one or more embodiments, Ar601 in Formula 601 may be a substituted or unsubstituted anthracene group.
In one or more embodiments, the electron transport region 133 may include a compound represented by Formula 601-1:
wherein, in Formula 601,
X614 may be N or C(R614), X615 may be N or C(R615), X616 may be N or C(R616), at least one of X614 to X616 may be N,
L611 to L613 are the same as described in connection with L601,
xe611 to xe613 are the same as described in connection with xe1,
R611 to R613 are the same as described in connection with 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 133 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 (Alq3), bis(2-methyl-8-quinolinolato-N1,08)-(1,1′-biphenyl-4-olato)aluminum (BAlq), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), or any combination thereof:
The thickness of the electron transport region 133 may be from about 160 Å to about 5,000 Å, for example, about 100 Å to about 4,000 Å. When the electron transport region 133 includes the buffer layer, the hole blocking layer 133a, the electron control layer, the electron transport layer 133b, or any combination thereof, the thickness of the buffer layer, the hole blocking layer 133a, or the electron control layer may each independently be from about 20 A to about 1,000 Å, for example, about 30 Å to about 300 Å, and the thickness of the electron transport layer 133b may be from about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thicknesses of the buffer layer, the hole blocking layer 133a, the electron control layer, the electron transport layer 133b and/or the electron transport layer 133b are within these ranges, satisfactory electron transporting characteristics may be obtained without a substantial increase in driving voltage. The electron transport region 133 (for example, the electron transport layer 133b in the electron transport region 133) 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 any combination thereof. A metal ion of the alkali metal complex may be a Li ion, a Na ion, a K ion, a Rb ion, or a Cs ion, and a metal ion of the 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 any combination thereof.
For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:
The electron transport region 133 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, 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 any combination thereof.
The alkali metal may include Li, Na, K, Rb, Cs, or any combination thereof. The alkaline earth metal may include Mg, Ca, Sr, Ba, or any combination thereof. The rare earth metal may include Sc, Y, Ce, Tb, Yb, Gd, or any 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 any 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 any combination thereof. The alkaline earth metal-containing compound may include an alkaline earth metal compound, such as BaO, SrO, CaO, BaxSr1-xO (x is a real number satisfying the condition of 0<x<1), BaxCa1-xO (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 one or more embodiments, the rare earth metal-containing compound may include a 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, and the rare earth metal and ii), as a ligand bonded to the metal ion, for example, a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenyl benzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof.
The electron injection layer may consist of 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 any combination thereof, as described above. In one or more embodiments, the electron injection layer may further include an organic material (for example, a compound represented by Formula 601).
In one or more embodiments, the electron injection layer may consist of i) an alkali metal-containing compound (for example, an alkali metal halide), 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 any combination thereof. In one or more embodiments, the electron injection layer may be a KI:Yb co-deposited layer, a 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 any combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.
The 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 range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.
The second electrode 150 may be located on the interlayer 130 having such a structure. 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 any 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), an ITO, an indium zinc oxide (IZO), or any combination thereof. The second electrode 150 may be a light transmissive electrode, a semi-light transmissive electrode, or a light reflective electrode. The second electrode 150 may have a single-layered structure or a multi-layered structure including two or more 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 detail, the light-emitting device 10 may have a structure in which the first capping layer 160, the first electrode 110, the interlayer 130, and the second electrode 150 are sequentially stacked in this 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 this 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 this 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-light transmissive electrode or a light transmissive electrode, and the first capping layer or 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 light transmissive electrode, and the second capping layer.
Although not wanting to be bound by theory, 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 is increased, so that the emission efficiency of the light-emitting device 10 may be improved.
The first capping layer and second capping layer may each include a material having a refractive index (at about 589 nm) of about 1.6 or more. 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 a composite capping layer including an organic material and an inorganic material.
At least one selected from the first capping layer and the second capping layer may each independently include carbocyclic compounds, heterocyclic compounds, amine group-containing compounds, porphyrin derivatives, phthalocyanine derivatives, a naphthalocyanine derivatives, alkali metal complexes, alkaline earth metal complexes, or any combination thereof. The carbocyclic compound, the heterocyclic compound, and the amine group-containing compound may be optionally substituted with a substituent containing O, N, S, Se, Si, F, Cl, Br, I, or any combination thereof. In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include an amine group-containing compound.
In one or more embodiments, 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 any combination thereof.
In one or more embodiments, 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, N4,N4′-di(naphthalen-2-yl)-N4,N4′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (β-NPB), or any combination thereof:
The light-emitting device 10 may be included in various electronic apparatuses. In an embodiment, the electronic apparatus including the light-emitting device 10 may be a light-emitting apparatus, an authentication apparatus, or the like.
The electronic apparatus (for example, light-emitting apparatus) may further include, in addition to the light-emitting device, 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 located in at least one traveling direction of light emitted from the light-emitting device. In an embodiment, the light emitted from the light-emitting device 10 may be blue light or white light. The light-emitting device 10 may be the same as described above. In an embodiment, the color conversion layer may include quantum dots. The quantum dot may be, for example, a quantum dot as described herein. The electronic apparatus 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 include a plurality of color conversion areas and light-shielding patterns located among the color conversion areas.
The color filter areas (or the 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, and the first-color light, the second-color light, and/or the third-color light may have different maximum emission wavelengths from one another. In one or more embodiments, 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. In one or more embodiments, the color filter areas (or the color conversion areas) may include quantum dots. In detail, 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. The quantum dot is the same as described herein. The first area, the second area, and/or the third area may each include a scatter.
In one or more embodiments, the light-emitting device 10 may emit first light, the first area may absorb the first light to emit first first-color light, the second area may absorb the first light to emit second first-color light, and the third area may absorb the first light to emit third first-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 detail, 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 apparatus may further include a thin-film transistor in addition to the light-emitting device 10 as described above. The thin-film transistor may include a source electrode, a drain electrode, and an activation layer, wherein any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the light-emitting device 10.
The thin-film transistor may further include a gate electrode, a gate insulating film, etc. The activation layer may include a crystalline silicon, an amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like. The electronic apparatus may further include a sealing portion for sealing the light-emitting device 10. The sealing portion and/or the color conversion layer may be placed between the color filter 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 apparatus 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 apparatus. 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 light-emitting device 10, a biometric information collector.
The electronic apparatus may take the form of or 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 activation layer 220 may include an inorganic semiconductor such as a silicon or a 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 is located on the gate electrode 240. The interlayer insulating film 250 may be placed between the gate electrode 240 and the source electrode 260 to insulate the gate electrode 240 from the source electrode 260 and between the gate electrode 240 and the drain electrode 270 to insulate the gate electrode 240 from the drain electrode 270.
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 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 by a passivation layer 280. The passivation layer 280 may include an inorganic insulating film, an organic insulating film, or any 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 formed on the passivation layer 280. The passivation layer 280 does not completely cover the drain electrode 270 and exposes a portion of the drain electrode 270, and the first electrode 110 is connected to the exposed portion of the drain electrode 270.
A pixel defining layer 290 containing an insulating material may be located on the first electrode 110. The pixel defining layer 290 exposes a 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 a polyacrylic organic film. Although not shown in
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 10 from moisture or oxygen. The encapsulation portion 300 may include: an inorganic film including a silicon nitride (SiNx), a silicon oxide (SiOx), an indium tin oxide, an indium zinc oxide, or any combination thereof, an organic film including a polyethylene terephthalate, a polyethylene naphthalate, a polycarbonate, a polyimide, a polyethylene sulfonate, a polyoxymethylene, a polyarylate, a hexamethyldisiloxane, an acrylic resin (for example, a polymethyl methacrylate, a polyacrylic acid, or the like), an epoxy-based resin (for example, an aliphatic glycidyl ether (AGE), or the like), or any combination thereof, or any combination of the inorganic film and the organic film.
The light-emitting apparatus of
Respective layers included in the hole transport region 131, the emission layer 132, and respective layers included in the electron transport region 133 may be formed in a certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.
When layers constituting the hole transport region 131, the emission layer 132, and layers constituting the electron transport region 133 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 torr, and a deposition speed of about 0.01 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.
As used herein, the term “atomic percent” means the percentage of one kind of atom relative to the total number of atoms.
As used herein, the term “AlNiLa” refers to an aluminum-nickel-lanthanum alloy, and, for example, an amount of nickel may be in a range of about 1 atomic percent to about 3 atomic percent, and an amount of lanthanum may be in a range of about 0.1 atomic percent to about 0.5 atomic percent.
As used herein, the term “AlNd” refers to an aluminum-neodymium alloy, and, for example, an amount of neodymium may be in a range of about 1 atomic percent to about 3 atomic percent.
As used herein, the term “AlNiGeLa” refers to an aluminum-nickel-germanium-lanthanum alloy, and, for example, an amount of nickel may be in a range of about 1 atomic percent to about 3 atomic percent, an amount of germanium may be in a range of about 1 atomic percent to about 3 atomic percent, and an amount of lanthanum may be in a range of about 0.01 atomic percent to about 0.2 atomic percent.
As used herein, the term “AlCoGeLa” refers to an aluminum-cobalt-germanium-lanthanum alloy, and, for example, an amount of cobalt may be in a range of about 1 atomic percent to about 3 atomic percent, an amount of germanium may be in a range of about 1 atomic percent to about 3 atomic percent, and an amount of lanthanum may be in a range of about 0.01 atomic percent to about 0.2 atomic percent.
The term “interlayer” as used herein refers to a single layer and/or all of a plurality of layers located between a first electrode and a second electrode of a light-emitting device.
As used herein, the term “energy level” may be abbreviated “eV” and the term “blue efficiency” may be expressed in units of candelas per area (meter-squared) per year and abbreviated (cd/A/y).
A quantum dot as used herein refers to a crystal of a semiconductor compound, and may include any material capable of emitting light of various emission wavelengths according to the size of the crystal.
As used herein, the term “atom” may mean an element or its corresponding radical bonded to one or more other atoms.
The terms “hydrogen” and “deuterium” refer to their respective atoms and corresponding radicals with the deuterium radical abbreviated “-D”, and the terms “—F, —Cl, —Br, and —I” are radicals of, respectively, fluorine, chlorine, bromine, and iodine.
As used herein, a substituent for a monovalent group, e.g., alkyl, may also be, independently, a substituent for a corresponding divalent group, e.g., alkylene.
The term “C3-C60 carbocyclic group” as used herein refers to a cyclic group consisting of carbon only 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. 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 fused with each other. For example, the number of ring-forming atoms of the C1-C60 heterocyclic group may be from 3 to 61.
The “cyclic group” as used herein may include the C3-C60 carbocyclic group, and the C1-C60 heterocyclic group.
The term “n 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 “n 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 fused cyclic group in which two or more groups T1 are fused 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 fused cyclic group in which two or more groups T2 are fused with each other, or iii) a fused cyclic group in which at least one group T2 and at least one group T1 are fused 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 fused cyclic group in which two or more groups T1 are fused with each other, iii) group T3, iv) a fused cyclic group in which two or more groups T3 are fused with each other, or v) a fused cyclic group in which at least one group T3 and at least one group T1 are fused with each other, for example, the C3-C60 carbocyclic group, 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, etc.
The π electron-deficient nitrogen-containing C1-C60 cyclic group may be i) group T4, ii) a fused cyclic group in which two or more groups T4 are fused with each other, iii) a fused cyclic group in which at least one group T4 and at least one group T1 are fused with each other, iv) a fused cyclic group in which at least one group T4 and at least one group T3 are fused with each other, or v) a fused cyclic group in which at least one group T4, at least one group T1, and at least one group T3 are fused 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.
The 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.
The 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, or a tetrazine group.
The group T3 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, or a borole group.
The 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 π electron-deficient nitrogen-containing C1-C60 cyclic group” as used herein refer to a group fused to any cyclic group or a polyvalent group (for example, a divalent group, a trivalent group, a tetravalent group, etc.), depending on the structure of a formula in connection with which the terms are used. In one or more embodiments, “a benzene group” may be a benzo group, a phenyl group, a phenylene group, or the like, which may be easily understood 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 are 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 fused polycyclic group, and a monovalent non-aromatic fused heteropolycyclic group, and examples of the divalent C3-C60 carbocyclic group and the monovalent C1-C60 heterocyclic group are 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 fused polycyclic group, and a substituted or unsubstituted divalent non-aromatic fused 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 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 a structure corresponding to 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 a structure corresponding to 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 and a propynyl group. The term “C2-C60 alkynylene group” as used herein refers to a divalent group having a structure corresponding to 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 cyclic group having 3 to 10 carbon atoms, and examples thereof are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group (or bicyclo[2.2.1]heptyl group), a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, and a bicyclo[2.2.2]octyl group. The term “C3-C10 cycloalkylene group” as used herein refers to a divalent group having a structure corresponding to the C3-C10 cycloalkyl group.
The term “C1-C10 heterocycloalkyl group” as used herein refers to a monovalent cyclic group that further includes, in addition to a carbon atom, at least one heteroatom as a ring-forming atom and has 1 to 10 carbon atoms, and examples thereof 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 a structure corresponding to 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 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 a structure corresponding to the C3-C10 cycloalkenyl group.
The term “C1-C10 heterocycloalkenyl group” as used herein refers to a monovalent cyclic group that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, 1 to 10 carbon atoms, and 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 a structure corresponding to the C1-C10 heterocycloalkenyl group.
The term “C6-C60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having six to sixty carbon atoms, and the term “C6-C60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having six to sixty 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 fused with each other.
The term “C1-C60 heteroaryl group” as used herein refers to a monovalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. The term “C1-C60 heteroarylene group” as used herein refers to a divalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon 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 fused with each other.
The term “monovalent non-aromatic fused polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings fused to each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic fused 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 fused polycyclic group” as used herein refers to a divalent group having a structure corresponding to a monovalent non-aromatic fused polycyclic group.
The term “monovalent non-aromatic fused heteropolycyclic group” as used herein refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings fused to each other, at least one heteroatom other than carbon atoms, as a ring-forming atom, and non-aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic fused heteropolycyclic group are a pyrrolyl group, a thiophenyl group, a furanyl group, an indolyl group, a benzoindolyl group, a naphtho indolyl group, an isoindolyl group, a benzoisoindolyl group, a naphthoisoindolyl group, a benzosilolyl group, a benzothiophenyl group, a benzofuranyl group, a carbazolyl group, a dibenzosilolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, an azacarbazolyl group, an azafluorenyl group, an azadibenzosilolyl group, an azadibenzothiophenyl group, an azadibenzofuranyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzopyrazolyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a benzoxadiazolyl group, a benzothiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an imidazotriazinyl group, an imidazopyrazinyl group, an imidazopyridazinyl group, an indenocarbazolyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a benzosilolocarbazolyl group, a benzoindolocarbazolyl group, a benzocarbazolyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, a benzonaphthosilolyl group, a benzofurodibenzofuranyl group, a benzofurodibenzothiophenyl group, and a benzothienodibenzothiophenyl group. The term “divalent non-aromatic heterofused polycyclic group” as used herein refers to a divalent group having a structure corresponding to a monovalent non-aromatic heterofused polycyclic group.
The term “C6-C60 aryloxy group” as used herein indicates —OA102 (wherein A102 is the C6-C60 aryl group), and the term “C6-C60 arylthio group” as used herein indicates —SA103 (wherein A103 is the C6-C60 aryl group).
The term “R10a” as used herein refers to:
deuterium (-D), —F, —Cl, —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, —Cl, —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, —Si(Q11)(Q12)(Q13), —N(Q11)(Q12), —B(Q11)(Q12), —C(═O)(Q11), —S(═O)2(Q11), —P(═O)(Q11)(Q12), or any combination thereof;
a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, or a C6-C60 arylthio 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, —Si(Q21)(Q22)(Q23), —N(Q21)(Q22), —B(Q21)(Q22), —C(═O)(Q21), —S(═O)2(Q21), —P(═O)(Q21)(Q22), or any 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).
The variables Q1, 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; C1-C60 alkyl group; C2-C60 alkenyl group; C2-C60 alkynyl group; C1-C60 alkoxy group; or 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.
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, and any combination thereof.
As used herein, the term “Ph” represents a phenyl group, the term “Me” represents a methyl group, the term “Et” represents an ethyl group, the term “ter-Bu” or “But” represents a tert-butyl group, and the term “OMe” represents 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.
The symbols * and *′ as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.
Hereinafter, a light-emitting device according to embodiments will be described in detail with reference to Examples.
As an anode, the compound AlNiLa was sputtered on a glass substrate to form a reflective film having a thickness of 1,000 Å, and the compound WO3 was sputtered on the anode to form a hole injection layer having a thickness of 70 Å. Thereafter, the anode and the hole injection layer were patterned, and then, dry etching was performed thereon.
The dry etching was carried out by injecting a mixed gas of Cl2 and BCl2 of about 10 milliTorr in a chamber.
The compound HT3 was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 300 Å. The compound m-MTDATA was vacuum-deposited on the hole transport layer to form an electron blocking layer having a thickness of 300 Å.
The compounds ADN and DPAVBi (the amount of DPAVBi was 5 wt % with the remaining the compound ADN) were co-deposited on the electron blocking layer to form an emission layer having a thickness of 300 Å.
The compound BAlq was deposited on the emission layer to form a hole blocking layer having a thickness of 300 Å, The compound ET1 was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å, the element Yb was deposited on the electron transport layer to form an electron injection layer having a thickness of 13 Å, and the elements Ag and Mg were co-deposited at a weight ratio of 10:1 on the electron injection layer to form a cathode having a thickness of 100 Å, thereby completing the manufacture of a light-emitting device.
The HOMO energy level of a material is measured using cyclic voltammetry, and a cyclic voltammetry apparatus used herein is the model name ZIVE SP2 available from Wonatech Co., Ltd of Seoul, Republic of Korea. In this regard, respective sample solutions and electrolytic solutions used herein are as follows, and ferrocene was used as the reference material, and (Bu)4NPF6 was used as the electrolyte. The measured sample solutions were 5×10−3 M dichloromethane solution, a ferrocene sample solution, 5×10−3 M dichloromethane solution; a (Bu)4NPF6 electrolytic solution, and 0.1 M acetonitrile solution.
An Ewe-I relationship graph of compounds to be measured and a reference material was obtained, and, at the point where the current rapidly increases in the graph, the voltage at the point where the tangent lines meet the x-axis is recorded. The HOMO energy level of ferrocene was set to −4.8 eV, and the HOMO energy level of a material to be measured was calculated.
The material was spin-coated on an indium tin oxide (ITO) substrate to form a thin film having a thickness of 50 nm and heat-treated on a hot plate in air at a temperature of 200° C. for 5 minutes, and then, a work function thereof was evaluated. As an apparatus for evaluation, an ultraviolet photoelectron spectroscopy (UPS, Thermo) was used.
Work function of hole transport layer (WO3): −5.5 eV
EHOMO_HTL: −5.15 eV
A light-emitting device was manufactured in the same manner as in Example 1, except that the thickness of the hole injection layer was adjusted to be 700 Å.
Work function of hole injection layer: −5.5 eV
EHOMO_HTL: −5.15 eV
As a substrate and an anode, a first glass substrate obtained from Samsung-Corning of Asan, Republic of Korea (hereinafter Corning), having 15 Ω/cm2 (70 Å) ITO formed thereon, a second glass substrate having Ag (700 Å) formed thereon, and a third glass obtained from Corning, 15 Ω/cm2 (70 Å) ITO formed thereon were each cut to a size of 50 mm×50 mm×0.7 mm, which was then sonicated with isopropyl alcohol and pure water each for 5 minutes, followed by irradiation with ultraviolet light for 30 minutes and exposure to ozone. Then, the glass substrates were provided to a vacuum deposition apparatus.
The compounds HT3 and 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) were deposited at a ratio of 95:5 on the ITO anode formed on the glass substrates to form a hole injection layer having a thickness of 100 Å. The compound HT3 was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 300 Å.
The compounds ADN and DPAVBi (the amount of DPAVBi was 5 wt %, the remaining being the compound ADN) were co-deposited on the hole transport layer to form an emission layer having a thickness of 300 Å.
The compound BAlq was deposited on the emission layer to form a hole blocking layer having a thickness of 300 Å, the compound ET1 was deposited on the hole blocking layer form an electron transport layer having a thickness of 300 Å, the element Yb was deposited on the electron transport layer to form an electron injection layer having a thickness of 13 Å, and the elements Ag and Mg were co-deposited at a weight ratio of 10:1 on the electron injection layer to form a cathode having a thickness of 100 Å, thereby completing the manufacture of a light-emitting device.
A light-emitting device was manufactured in the same manner as in Comparative Example 1, except that a first glass substrate with AlNiLa (1,000 Å) formed thereon and a second glass substrate obtained from Corning 15 Ω/cm2 (70 Å) ITO formed thereon were used as the substrate and the anode.
A light-emitting device was manufactured in the same manner as in Comparative Example 1, except that the compound HAT-CN was not included in the hole injection layer.
A light-emitting device was manufactured in the same manner as in Comparative Example 3, except that a third glass substrate was not used, and the element WO3 was deposited on the anode to form a hole injection layer having a thickness of 70 Å.
A light-emitting device was manufactured in the same manner as in Example 1, except that the compounds HT3 and HAT-CN were deposited at a weight ratio of 95:5 on the hole injection layer to form a hole transport layer having a thickness of 100 Å.
A light-emitting device was manufactured in the same manner as in Example 1, except that the compounds In2O3 and SnO2 were sputter-deposited at a weight ratio of 90:10 to form a hole injection layer having a thickness of 600 Å.
Work function of hole injection layer (the compounds In2O3 and SnO2 at weight ratio of 90:10): −4.8 eV
EHOMO_HTL: −5.15 eV
The driving voltage, efficiency, and lifespan of the light-emitting devices manufactured according to Examples 1 and 2 and Comparative Examples 1 to 6 were measured by using a color luminance meter sold (Topcon, SR3UL2 model), a source-measure unit sold (McScience V7000) and a fixed current room-temperature lifespan apparatus, and results thereof are shown in Table 1.
Table 1 shows that the light-emitting devices of Examples 1 and 2 had significant and unexpectedly superior characteristics in terms of a low driving voltage, high luminescence efficiency, and a long lifespan, as compared with the light-emitting devices of Comparative Examples 1 to 6.
By introducing a metal oxide satisfying certain conditions in the hole injection layer, the light-emitting devices constructed according to the principles and embodiments of the invention may exhibit driving voltage, efficiency, and lifespan equivalent to those of light-emitting devices of the related art, while reducing production costs by simplifying manufacturing by the omission of a p-doping layer, and may have improved color purity and color accuracy while minimizing or preventing the occurrence of mixing of colors caused by a leakage current. In addition, the application of an Al-based anode may prevent a decrease in the efficiency of the light-emitting devices.
Although certain embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concepts are not limited to such embodiments, but rather to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as would be apparent to a person of ordinary skill in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0012649 | Jan 2021 | KR | national |
