Patent Grant
12048243
This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2020-0051054, filed on Apr. 27, 2020, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2021-0050745, filed on Apr. 19, 2021, in the Korean Intellectual Property Office, the contents of which are incorporated by reference herein in their entirety.
The presently claimed invention was made by or on behalf of the below listed parties to a joint research agreement. The joint research agreement was in effect on or before the date the claimed invention was made, and the claimed invention was part of the joint research agreement and made as a result of activities undertaken within the scope of the joint research agreement. The parties to the joint research agreement are Samsung Electronics Co., Ltd. and Research & Business Foundation, Sungkyunkwan University.
Provided are a composition satisfying a certain condition and an organic light-emitting device including the same.
Organic light-emitting devices are self-emission devices that produce full-color images, and also have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of luminance, driving voltage, and response speed, compared to devices in the art.
In an example, an organic light-emitting device includes an anode, a cathode, and an organic layer between the anode and the cathode, wherein the organic layer includes an emission layer. A hole-transporting region may be located between the anode and the emission layer, and an electron-transporting region may be located between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole-transporting region, and electrons provided from the cathode may move toward the emission layer through the electron-transporting region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state to thereby generate light.
Provided are a composition satisfying a certain condition and an organic light-emitting device including the same.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
According to an aspect, an organic light-emitting device includes a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer includes an emission layer, the emission layer includes a first compound, a second compound, a third compound, and a fourth compound, the first compound and the second compound forms an exciplex, the exciplex and the third compound satisfy Conditions 1-1 and 1-2, and the fourth compound is represented by Formula 503.
T1(Ex)≤T1(C3)<S1(Ex) Condition 1-1
T1(C3)−T1(Ex)<0.3 eV Condition 1-2
In Conditions 1-1 and 1-2,
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer includes an emission layer, the emission layer includes a first compound, a third compound, and a fourth compound, the first compound and the third compound satisfy Conditions 1-3 and 1-4, and the fourth compound is represented by Formula 503.
T1(C1)≤T1(C3)<S1(C1) Condition 1-3
T1(C3)−T1(C1)<0.3 eV Condition 1-4
In Conditions 1-3 and 1-4,
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, m light-emitting units located between the first electrode and the second electrode and including at least one emission layer, and m−1 charge generating layers located between neighboring two light-emitting units of the m light-emitting units and including an n-type charge generating layer and a p-type charge generating layer, wherein m is an integer of 2 or more, a maximum emission wavelength of light emitted from at least one light-emitting unit of the m light-emitting units is different from a maximum emission wavelength of light emitted from at least one light-emitting unit of the remaining light-emitting units, at least one of the emission layers includes a first compound, a second compound, a third compound, and a fourth compound, the first compound and the second compound form an exciplex, the exciplex and the third compound satisfy Conditions 1-1 and 1-2, and the fourth compound is represented by Formula 503.
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, m light-emitting units located between the first electrode and the second electrode and including at least one emission layer, and m−1 charge generating layers located between neighboring two light-emitting units of the m light-emitting units and including an n-type charge generating layer and a p-type charge generating layer, wherein m is an integer of 2 or more, a maximum emission wavelength of light emitted from at least one light-emitting unit of the m light-emitting units is different from a maximum emission wavelength of light emitted from at least one light-emitting unit of the remaining light-emitting units, at least one of the emission layers includes a first compound, a third compound, and a fourth compound, the first compound and the third compound satisfy Conditions 1-3 and 1-4, and the fourth compound is represented by Formula 503.
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, and m emission layers between the first electrode and the second electrode, wherein m is an integer of 2 or more, a maximum emission wavelength of light emitted from at least one emission layer of the m emission layers is different from a maximum emission wavelength of light emitted from at least one emission layer of the remaining emission layers, at least one of the m emission layers includes a first compound, a second compound, a third compound, and a fourth compound, the first compound and the second compound form an exciplex, the exciplex and the third compound satisfy Conditions 1-1 and 1-2, and the fourth compound is represented by Formula 503.
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, m emission layers between the first electrode and the second electrode, wherein m is an integer of 2 or more, a maximum emission wavelength of light emitted from at least one emission layer of the m emission layers is different from a maximum emission wavelength of light emitted from at least one emission layer of the remaining emission layers, at least one of the m emission layers includes a first compound, a third compound, and a fourth compound, the first compound and the third compound satisfy Conditions 1-3 and 1-4, and the fourth compound is represented by Formula 503.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present
It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a,” “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to cover both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise.
“Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or a group thereof.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the Figures It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements The exemplary term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10% or 5% of the stated value.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features Moreover, sharp angles that are illustrated may be rounded Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.
Description of
The organic light-emitting device 10 of
The organic layer 10A includes an emission layer 15, a hole-transporting region 12 may be located between the first electrode 11 and the emission layer 15, and an electron-transporting region 17 may be located between the emission layer 15 and the second electrodes 19.
A substrate may be additionally located under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate that is used in organic light-emitting devices available in the art may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.
First Electrode 11
In one or more embodiments, the first electrode 11 may be formed by depositing or sputtering a material for forming the first electrode 11 on the substrate. The first electrode 11 may be an anode. The material for forming the first electrode 11 may be a material with a high work function to facilitate hole injection.
The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 11 is a transmissive electrode, a material for forming a first electrode may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), or any combinations thereof, but embodiments of the disclosure are not limited thereto. In an embodiment, when the first electrode 110 is a semi-transmissive electrode or a reflective electrode, a material for forming the first electrode 110 may be magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or any combination thereof, but embodiments of the disclosure are not limited thereto.
The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers.
Emission Layer 15
The emission layer 15 includes a first compound, a second compound, a third compound, and a fourth compound. In an embodiment, the emission layer 15 may consist of a first compound, a second compound, a third compound, and a fourth compound. That is, the emission layer 15 may not further include a material other than the first compound, the second compound, the third compound, and the fourth compound.
The first compound and the second compound form an exciplex. The exciplex is a complex in an excited state and formed between the first compound and the second compound.
Because the first compound and the second compound form an exciplex, despite a relatively high T1 energy level, the first compound and the second compound may be stable. Accordingly, the lifespan of an organic light-emitting device including the first compound and the second compound may be improved.
The exciplex and the third compound may satisfy Condition 1-1:
T1(Ex)≤T1(C3)<S1(Ex) Condition 1-1
T1(Ex) is a value calculated from an onset wavelength of a photoluminescence (PL) spectrum at low temperature with respect to a film (hereinafter, referred to as a “film (Ex)”) having a thickness of 40 nm obtained by vacuum-codepositing, on a quartz substrate, the first compound and the second compound included in the emission layer 15 at a certain weight ratio and a vacuum pressure of 10−7 torr. A detailed method of evaluating T1(Ex) is the same as described in connection with examples below.
T1(C3) is a value calculated from an onset wavelength of a PL spectrum at low temperature with respect to a sample (hereinafter, referred to as a “sample (C3)”) obtained by dissolving the third compound included in the emission layer 15 in toluene at a concentration of 1×10−4M in a quartz cell. A detailed method of evaluating T1(C3) is the same as described in connection with examples below.
S1(Ex) is a value calculated from an onset wavelength of a PL spectrum at room temperature with respect to a film (hereinafter, referred to as a “film (Ex)”) having a thickness of 40 nm obtained by vacuum-codepositing, on a quartz substrate, the first compound and the second compound included in the emission layer 15 at a certain weight ratio and a vacuum pressure of 10−7 torr. A detailed method of evaluating S1(Ex) is the same as described in connection with examples below.
By satisfying Condition 1-1, the organic light-emitting device may have an improved lifespan. In general, it is known that since triplet excitons stay long in an excited state, they influence the decrease in the lifespan of organic light-emitting devices. However, in the disclosure, a lowest excited triplet energy level of an exciplex is reduced to improve the lifespan of organic light-emitting devices including the exciplex.
The exciplex and the third compound may satisfy Condition 1-2:
T1(C3)−T1(Ex)<0.3 eV Condition 1-2
The organic light-emitting device satisfies Condition 1-2, and thus because a triplet exciton of the exciplex may be rapidly converted to a triplex exciton of the third compound, the organic light-emitting device may have an implementable level of efficiency.
That is, the organic light-emitting device satisfies Conditions 1-1 and 1-2 at the same time, and thus, may have an improved lifespan and an improved efficiency.
In an embodiment, the exciplex and the third compound may further satisfy Condition 1-2-1:
T1(C3)−T1(Ex)≤0.15 eV Condition 1-2-1
wherein, in Condition 1-2-1, definitions of T1(Ex) and T1(C3) are each the same as described above.
Each of the first compound and the second compound may not include a metal atom.
In an embodiment, the first compound may be a hole transporting host, and the second compound may be an electron transporting host.
The electron transporting host may include at least one electron transporting moiety. The hole transporting host may not include an electron transporting moiety.
The electron transporting moiety used herein may be a cyano group, —F, —CFH2, —CF2H, —CF3, a π electron-deficient nitrogen-containing cyclic group, and a group represented by one of the following formulae:
In the formulae, *, *′ and *″ are each binding sites to neighboring atoms.
In an embodiment, the electron transporting host may include at least one of a cyano group, a π electron-deficient nitrogen-containing cyclic group, or a combination thereof.
In an embodiment, the electron transporting host may include at least one cyano group.
In an embodiment, the electron transporting host may include at least one cyano group, at least one π electron-deficient nitrogen-containing cyclic group, or a combination thereof.
In an embodiment, the hole transporting host may include at least one u electron-deficient nitrogen-free cyclic group, and may not include an electron transporting moiety.
The term “electron-deficient nitrogen-containing cyclic group” used herein refers to a cyclic group having at least one *—N═*′ moiety, and for example, may be: an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, a benzoisoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, and an azacarbazole group; and a condensed cyclic group in which two or more π electron-deficient nitrogen-containing cyclic a group are condensed with each other.
The term “T electron-deficient nitrogen-free cyclic group” used herein may be, for example: a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentaphene group, a rubicene group, a coronene group, an ovalene group, a pyrrole group, an isoindole group, an indole group, a furan group, a thiophene group, a benzofuran group, a benzothiophene group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzothiophene sulfone group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, and a triindolobenzene group; and a condensed cyclic group in which two or more π electron-deficient nitrogen-free cyclic a group are condensed with each other, but embodiments of the disclosure are not limited thereto.
In an embodiment, the electron transporting host may be a compound represented by Formula E-1, and the hole transporting host may be a compound represented by Formula H-1, but embodiments of the disclosure are not limited thereto:
[Ar301]xb11-[(L301)xb1-R301]xb21 Formula E-1
wherein, in Formula E-1,
Condition B
L301 in Formula E-1 is a group represented by one of the following a group
Condition C
R301 in Formula E-1 may be a cyano group, —S(═O)2(Q301), —S(═O)(Q301), —P(═O)(Q301)(Q302), or —P(═S)(Q301)(Q302).
In Formulae H-1, 11, and 12,
In an embodiment, Ar301 and L301 in Formula E-1 may each independently be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, or an azacarbazole group, each unsubstituted or substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, a cyano-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q31)(Q32)(Q33), —N(Q31)(Q32), —B(Q31)(Q32), —C(═O)(Q31), —S(═O)2(Q31), or —P(═O)(Q31)(Q32),
In an embodiment, Ar301 may be: a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, or a dibenzothiophene group, each unsubstituted or substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, a cyano-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q31)(Q32)(Q33), —N(Q31)(Q32), —B(Q31)(Q32), —C(═O)(Q31), —S(═O)2(Q31), —P(═O)(Q31)(Q32), or any combination thereof; or
Q31 to Q33 are each the same as described above.
In an embodiment, L301 may be a group represented by Formulae 5-2, 5-3, or 6-8 to 6-33.
In an embodiment, R301 may be a cyano group or a group represented by Formulae 7-1 to 7-18, and at least one of Ar402(s) in the number of xd11 may be a group represented by Formulae 7-1 to 7-18, but embodiments of the disclosure are not limited thereto:
Two or more Ar301(s) in Formula E-1 may be identical to or different from each other, two or more of L301(s) may be identical to or different from each other, two or more of L401(s) in Formula H-1 may be identical to or different from each other, and two or more of Ar402(s) in Formula H-1 may be identical to or different from each other.
The electron transporting host may be, for example, a group HE1 to HE7, but embodiments of the disclosure are not limited thereto:
A weight ratio of the first compound to the second compound may be 1:9 to 9:1, for example, 2:8 to 8:2, for example, 4:6 to 6:4, for example, 5:5.
The third compound may be a phosphorescent dopant or a delayed fluorescence dopant. However, the third compound may not substantially emit light.
The phosphorescent dopant may be an organic metal compound including at least one metal a first-row transition metal of the Periodic Table of Elements, a second-row transition metal of the Periodic Table of Elements, a third-row transition metal of the Periodic Table of Elements, or a combination thereof.
In an embodiment, the phosphorescent dopant may include metal (M11) of at least one a first-row transition metal of the Periodic Table of Elements, a second-row transition metal of the Periodic Table of Elements, a third-row transition metal of the Periodic Table of Elements, or a combination thereof, and an organic ligand (L11), and L11 and M11, may form 1, 2, 3, or 4 cyclometallated rings.
In an embodiment, the phosphorescent dopant may include an organometallic compound represented by Formula 101:
M11(L11)n11(L12)n12 Formula 101
In an embodiment, the phosphorescent dopant may be a group of PD1 to PD6, but embodiments of the disclosure are not limited thereto:
A compound represented by Formula A below:
(L101)n101-M101-(L102)m101 Formula A
In Table 1, AN1 to AN5 are each the same as described below:
LM1 to LM243 in Tables 1 to 3 may be understood by referring to Formulae 1-1 to 1-3 and Tables 4 to 6:
X1 to X10 and Y1 to Y18 in Tables 4 to 6 are each the same as described below, and Ph in the tables refers to a phenyl group:
The delayed fluorescence dopant may be a metal atom-free compound of which ΔEST is 0.2 eV or less. When ΔEST of the delayed fluorescence dopant is 0.2 eV or less, an up-conversion process due to reverse intersystem crossing (RISC) is advantageous, and thus, the efficiency of an organic light-emitting device including the delayed fluorescence dopant may be improved.
In an embodiment, the delayed fluorescence dopant may be represented by Formula 201 or 202:
In an embodiment, A21 in Formulae 201 and 202 may be a substituted or unsubstituted π electron-deficient nitrogen-free cyclic group.
In an embodiment, D21 in Formulae 201 and 202 may be: —F, a cyano group, or a π electron-deficient nitrogen-containing cyclic group;
In an embodiment, the π electron-deficient nitrogen-free cyclic group and the π electron-deficient nitrogen-containing cyclic group are each the same as described above.
In an embodiment, the delayed fluorescence dopant may be a group of DF1 to DF5, but embodiments of the disclosure are not limited thereto:
An amount of the third compound in the emission layer 15 may be from about 5 wt % to about 50 wt %. Within these ranges, it is possible to achieve effective energy transfer in the emission layer 15, and accordingly, an organic light-emitting device having high efficiency and long lifespan can be obtained.
The fourth compound may be represented by Formula 503:
In an embodiment, in Formula 503, X501 may be B, and Y501 to Y502 may each independently be O, S, or N(R505). In an embodiment, in Formula 503, X501 may be B, and Y501 to Y502 may each independently be O, or N(R505).
In an embodiment, the fourth compound may be represented by Formula 1 below:
In an embodiment, k11 in Formula 1 may be 0.
In an embodiment, A11 to A13 in Formula 1 may each independently be a group represented by Formula 10A, a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, or a perylene group;
In an embodiment, in Formula 1, A11 and A13 may each independently be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, or a perylene group; A12 may be a group represented by Formula 10A; or
In an embodiment, k11 and k101 in Formulae 1 and 10A may be 0.
In an embodiment, the fourth compound may be represented by Formula 1-1 or 1-2:
In an embodiment, the fourth compound may be Group BD1 below:
The fourth compound may be a fluorescent dopant emitting fluorescent light. Accordingly, a decay time (Tdecay(C4)) of the fourth compound may be less than 100 nanoseconds.
Tdecay(C4) is a value calculated from a time-resolved photoluminescence (TRPL) spectrum at room temperature with respect to a film having a thickness of 40 nm obtained by vacuum-codepositing, on a quartz substrate, the first compound, the second compound, and the fourth compound included in the emission layer 15 at a ratio of 45:45:10 and at a vacuum pressure of 10−7 torr. A detailed method of evaluating Tdecay(C4) is the same as described in connection with examples below.
A maximum emission wavelength of an emission spectrum of the fourth compound may be about 400 nm or more and about 550 nm or less. In an embodiment, the maximum emission wavelength of the emission spectrum of the fourth compound may be about 400 nm or more and about 495 nm or less, or about 450 nm or more and about 495 nm or less, but embodiments of the disclosure are not limited thereto. That is, the fourth compound may emit blue light. The “maximum emission wavelength” refers to a wavelength at which the emission intensity is the greatest, and may also be referred to as “a peak emission wavelength”.
An amount of the fourth compound in the emission layer 15 may be about 0.01 wt % to about 15 wt %, but embodiments of the disclosure are not limited thereto.
When the emission layer 15 further includes the fourth compound, the organic light-emitting device may further satisfy Condition 2 below:
T1(Ex)>T1(C4) Condition 2
T1(C4) is a value calculated from a PL spectrum at low temperature with respect to a film (hereinafter, referred to as a “film (C4)”) having a thickness of 40 nm obtained by vacuum-depositing, on a quartz substrate, the fourth compound included in the emission layer 15 at a vacuum pressure of 10−7 torr. A detailed method of evaluating T1(C4) is the same as described in connection with examples below.
When Condition 2 is further satisfied, the fourth compound may emit light. In an embodiment, when Condition 2 is further satisfied, the fourth compound emits light, and thus an organic light-emitting device with improved efficiency may be provided. In an embodiment, when Condition 2 is further satisfied, the light-emission ratio of the fourth compound in the organic light-emitting device may be about 85% or more. That is, when the range described above is satisfied, only the fourth compound substantially emits light in the organic light-emitting device, and the exciplex and the third compound may not substantially emit light.
In the first embodiment, a singlet and/or triplet exciton formed in the exciplex is transferred to the third compound, and then transferred again to the fourth compound via Förster resonance energy transfer (FRET). Because both the singlet exciton and the triplet exciton of the exciplex may be transmitted to the fourth compound, the organic light-emitting device may have a significantly improved lifespan and efficiency.
A thickness of the emission layer 15 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 15 is within these ranges, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.
The emission layer 15 includes a first compound, a third compound, and a fourth compound.
In an embodiment, the emission layer 15 may consist of a first compound, a third compound, and a fourth compound.
In an embodiment, the emission layer 15 may further include a second compound, and thus the emission layer 15 may consist of the first compound, the second compound, the third compound, and the fourth compound. In this regard, the first compound and the second compound may not form an exciplex.
The first compound and the third compound may satisfy Condition 1-3:
T1(C1)≤T1(C3)<S1(C1) Condition 1-3
wherein, in Condition 1-3,
T1(C1) is a value calculated from an onset wavelength of a PL spectrum at low temperature with respect to a film (hereinafter, referred to as a “film (C1)”) having a thickness of 40 nm obtained by vacuum-codepositing, on a quartz substrate, the first compound included in the emission layer 15 at a vacuum pressure of 10−7 torr. A detailed method of evaluating T1(C1) is the same as described in connection with examples below.
T1(C3) is a value calculated from an onset wavelength of a PL spectrum at low temperature with respect to a sample (hereinafter, referred to as a “sample (C3)”) obtained by dissolving the third compound included in the emission layer 15 in toluene at a concentration of 1×10−4 M in a quartz cell. A detailed method of evaluating T1(C3) is the same as described in connection with examples below.
S1(C1) is a value calculated from an onset spectrum at room temperature with respect to a film (hereinafter, referred to as a “film (C1)”) having a thickness of 40 nm obtained by vacuum-depositing, on a quartz substrate, the first compound included in the emission layer 15 at a vacuum pressure of 10−7 torr. A detailed method of evaluating S1(C1) is the same as described in connection with examples below.
By satisfying Condition 1-3, the organic light-emitting device may have an improved lifespan. In general, it is known that since triplet excitons stay long in an excited state, they influence the decrease in the lifespan of organic light-emitting devices. However, in the disclosure, a lowest excited triplet energy level of the first compound acting as a host is lowered to improve the lifespan of an organic light-emitting device including the first compound.
The first compound and the third compound may satisfy Condition 1-4:
T1(C3)−T1(C1)<0.3 eV Condition 1-4
The organic light-emitting device satisfies Condition 1-4, and thus because a triplet exciton of the first compound may be rapidly converted to a triplex exciton of the third compound, the organic light-emitting device may have an implementable level of efficiency.
That is, the organic light-emitting device satisfies Conditions 1-3 and 1-4 at the same time, and thus, may have an improved lifespan and efficiency.
In an embodiment, the first compound and the third compound may further satisfy Condition 1-4-1:
T1(C3)−T1(C1)−0.15 eV Condition 1-4-1
wherein, in Condition 1-4-1, definitions of T1(C1) and T1(C3) are each the same as described above.
Each of the first compound and the second compound may not include a metal atom.
In an embodiment, the first compound may be a hole transporting host, an electron transporting host, or a bipolar host. The hole transporting host and the electron transporting host are each the same as described above.
When the emission layer 15 further includes the second compound, the first compound and the second compound are each a hole transporting host, an electron transporting host, or a bipolar host. The hole transporting host and the electron transporting host are each the same as described above, and the bipolar host is the same as described below.
In an embodiment, the first compound may be a hole transporting host and the second compound may be an electron transporting host, the first compound may be an electron transporting host and the second compound may be a hole transporting host, the first compound and the second compound may each be a bipolar host, the first compound may be a hole transporting host and the second compound may be a bipolar host, the first compound may be an electron transporting host and the second compound may be a bipolar host, the first compound may be a bipolar host and the second compound may be a hole transporting host, or the first compound may be a bipolar host and the second compound may be an electron transporting host.
The third compound and the fourth compound are each the same as described in the first embodiment.
Hole-Transporting Region 12
The hole-transporting region 12 may be located between the first electrode 11 and the emission layer 15 of the organic light-emitting device 10.
The hole-transporting region 12 may have a single-layered structure or a multi-layered structure.
In an embodiment, the hole-transporting region 12 may have a hole injection layer, a hole-transporting layer, a hole injection layer/hole-transporting layer structure, a hole injection layer/first hole-transporting layer/second hole-transporting layer structure, a hole-transporting layer/middle layer structure, a hole injection layer/hole-transporting layer/middle layer structure, a hole-transporting layer/electron blocking layer structure, or a hole injection layer/hole-transporting layer/electron blocking layer structure, but embodiments of the disclosure are not limited thereto.
The hole-transporting region 12 may include any compound having hole-transporting properties.
In an embodiment, the hole-transporting region 12 may include an amine-based compound.
In an embodiment, the hole-transporting region 12 may include at least one of a compound represented by Formula 201 to a compound represented by Formula 205, but embodiments of the disclosure are not limited thereto:
In an embodiment,
In an embodiment, the hole-transporting region 12 may include a carbazole-containing amine-based compound.
In an embodiment, the hole-transporting region 12 may include a carbazole-containing amine-based compound and a carbazole-free amine-based compound.
The carbazole-containing amine-based compound may be, for example, a compound represented by Formula 201 including a carbazole group and further including at least one of a dibenzofuran group, a dibenzothiophene group, a fluorene group, a spiro-bifluorene group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, or a combination thereof.
The carbazole-free amine-based compound may be, for example, a compound represented by Formula 201 which does not include a carbazole group and which includes at least one a dibenzofuran group, a dibenzothiophene group, a fluorene group, a spiro-bifluorene group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, or a combination thereof.
In an embodiment, the hole-transporting region 12 may include at least one compound represented by Formulae 201 and 202.
In an embodiment, the hole-transporting region 12 may include at least one compound represented by Formulae 201-1, 202-1, 201-2, or a combination thereof, but embodiments of the disclosure are not limited thereto:
In an embodiment, the hole-transporting region 12 may include at least one of Compounds HT1 to HT39, but embodiments of the disclosure are not limited thereto.
In an embodiment, the hole-transporting region 12 of the organic light-emitting device 10 may further include a p-dopant. When the hole-transporting region 12 further includes a p-dopant, the hole-transporting region 12 may have a matrix (for example, at least one of compounds represented by Formulae 201 to 205) and a p-dopant included in the matrix. The p-dopant may be uniformly or non-uniformly doped in the hole-transporting region 12.
In an embodiment, a lowest unoccupied molecular orbital (LUMO) energy level of the p-dopant may be about −3.5 eV or less.
The p-dopant may include at least one of a quinone derivative, a metal oxide, a cyano group-containing compound, or a combination thereof, but embodiments of the disclosure are not limited thereto.
In an embodiment, the p-dopant may include at least one of:
The hole-transporting region 12 may have a thickness of about 100 Å to about 10000 Å, for example, about 400 Å to about 2000 Å, and the emission layer 15 may have a thickness of about 100 Å to about 3000 Å, for example, about 300 Å to about 1000 Å. When the thickness of each of the hole-transporting region 12 and the emission layer 15 is within these ranges described above, satisfactory hole transportation characteristics and/or luminescent characteristics may be obtained without a substantial increase in driving voltage.
Electron-Transporting Region 17
The electron-transporting region 17 may be placed between the emission layer 15 and the second electrode 19 of the organic light-emitting device 10.
The electron-transporting region 17 may have a single-layered structure or a multi-layered structure.
In an embodiment, the electron-transporting region 17 may have an electron-transporting layer, an electron-transporting layer/electron injection layer structure, a buffer layer/electron-transporting layer structure, a hole blocking layer/electron-transporting layer structure, a buffer layer/electron-transporting layer/electron injection layer structure, or a hole blocking layer/electron-transporting layer/electron injection layer structure, but embodiments of the disclosure are not limited thereto. The electron-transporting region 17 may further include an electron control layer.
The electron-transporting region 17 may include known electron-transporting materials.
The electron-transporting region 17 (for example, a buffer layer, a hole blocking layer, an electron control layer, or an electron-transporting layer in the electron-transporting region) may include a metal-free compound containing at least one π electron-deficient nitrogen-containing cyclic group. The π electron-deficient nitrogen-containing cyclic group is the same as described above.
In an embodiment, the electron-transporting region may include a compound represented by Formula 601 below:
[Ar601]xe11−[(L601)xe1−R601]xe21 Formula 601
In an embodiment, at least one of Ar601(s) in the number of xe11 and R601(s) in the number of xe21 may include the π electron-deficient nitrogen-containing cyclic group.
In an embodiment, ring Ar601 and L601 in Formula 601 may each independently be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, and an azacarbazole group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q31)(Q32)(Q33), —S(═O)2(Q31), or —P(═O)(Q31)(Q32),
When xe11 in Formula 601 is 2 or more, two or more of Ar601(s) may be linked to each other via a single bond.
In an embodiment, Ar601 in Formula 601 may be an anthracene group.
In an embodiment, a compound represented by Formula 601 may be represented by Formula 601-1 below:
In an embodiment, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.
In an embodiment, R601 and R611 to R613 in Formulae 601 and 601-1 may each independently be a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl 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 hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, or an azacarbazolyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl 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 hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, or an azacarbazolyl group; or
The electron-transporting region may include at least one compound of Compounds ET1 to ET36, but embodiments of the disclosure are not limited thereto:
In an embodiment, the electron-transporting region may include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-dphenyl-1,10-phenanthroline (Bphen), Alq3, BAlq, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), NTAZ, or a combination thereof.
Thicknesses of the buffer layer, the hole blocking layer, and the electron control layer may each independently be in the range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thicknesses of the buffer layer, the hole blocking layer, and the electron control layer are within these ranges, excellent hole blocking characteristics or excellent electron control characteristics may be obtained without a substantial increase in driving voltage.
A thickness of the electron-transporting layer may be in the range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron-transporting layer is within the range described above, the electron-transporting layer may have satisfactory electron-transporting characteristics without a substantial increase in driving voltage.
The electron-transporting region 17 (for example, the electron-transporting layer in the electron-transporting region) may further include, in addition to the materials described above, a metal-containing material.
The metal-containing material may include at least one alkali metal complex and alkaline earth-metal complex. 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 be a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, or a cyclopentadiene, but embodiments of the disclosure are not limited thereto.
In an embodiment, 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-transporting region 17 may include an electron injection layer that facilitates the injection of electrons from the second electrode 19. The electron injection layer may directly contact the second electrode 19.
The electron injection layer may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.
The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof.
The alkali metal may include Li, Na, K, Rb, or Cs. In an embodiment, the alkali metal may be Li, Na, or Cs. In an embodiment, the alkali metal may be Li or Cs, but embodiments of the disclosure are not limited thereto.
The alkaline earth metal may be Mg, Ca, Sr, or Ba.
The rare earth metal may be Sc, Y, Ce, Tb, Yb, or Gd.
The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may be oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth-metal, and the rare earth metal.
The alkali metal compound may be alkali metal oxides, such as Li2O, Cs2O, or K2O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI. In an embodiment, the alkali metal compound may be LiF, Li2O, NaF, LiI, NaI, CsI, or KI, but embodiments of the disclosure are not limited thereto.
The alkaline earth-metal compound may be alkaline earth-metal oxides, such as BaO, SrO, CaO, BaxSr1-xO (0<x<1), or BaxCa1-xO (0<x<1). In an embodiment, the alkaline earth-metal compound may be BaO, SrO, or CaO, but embodiments of the disclosure are not limited thereto.
The rare earth metal compound may be YbF3, ScF3, ScO3, Y2O3, Ce2O3, GdF3, or TbF3. In an embodiment, the rare earth metal compound may be YbF3, ScF3, TbF3, YbI3, Scl3, or Tbl3, but embodiments of the disclosure are not limited thereto.
The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth-metal, and rare earth metal as described above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth-metal complex, or the rare earth metal complex may be hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole, hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, or cyclopentadiene, but embodiments of the disclosure are not limited thereto.
The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof, as described above. In one or more embodiments, the electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal 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.
A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.
Second Electrode 19
The second electrode 19 is located on the organic layer 10A having such a structure. The second electrode 19 may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode 19 may be a metal, an alloy, an electrically conductive compound, or a combination thereof, which have a relatively low work function.
The second electrode 19 may include at least one of lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, IZO, or a combination thereof, but embodiments of the disclosure are not limited thereto. The second electrode 19 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.
The second electrode 19 may have a single-layered structure having a single layer or a multi-layered structure including two or more layers.
Hereinbefore, the organic light-emitting device has been described with reference to
Description of
The organic light-emitting device 100 of
The first light-emitting unit 151 may include a first emission layer 151-EM, and the second light-emitting unit 152 may include a second emission layer 152-EM. The maximum emission wavelength of light emitted from the first light-emitting unit 151 may be different from the maximum emission wavelength of light emitted from the second light-emitting unit 152. For example, the mixed light including the light emitted from the first light-emitting unit 151 and the light emitted from the second light-emitting unit 152 may be white light, but embodiments of the disclosure are not limited thereto.
The hole-transporting region 120 is located between the first light-emitting unit 151 and the first electrode 110, and the second light-emitting unit 152 may include the first hole-transporting region 121 located on the side of the first electrode 110.
An electron-transporting region 170 is located between the second light-emitting unit 152 and the second electrode 190, and the first light-emitting unit 151 may include a first electron-transporting region 171 located between the charge generation layer 141 and the first emission layer 151-EM.
The first emission layer 151-EM may include a first compound, a second compound, and a third compound, wherein the first compound and the second compound form an exciplex, and the exciplex and the third compound may satisfy Conditions 1-1 and 1-2 above.
The second emission layer 152-EM may include a first compound, a second compound, and a third compound, wherein the first compound and the second compound form an exciplex, and the exciplex and the third compound may satisfy Conditions 1-1 and 1-2 above.
The first electrode 110 and the second electrode 190 illustrated in
The first emission layer 151-EM and the second emission layer 152-EM illustrated in
The hole-transporting region 120 and the first hole-transporting region 121 illustrated in
The electron-transporting region 170 and the first electron-transporting region 171 illustrated in
As described above, referring to
Description of
The organic light-emitting device 200 includes a first electrode 210, a second electrode 290 facing the first electrode 210, and a first emission layer 251 and a second emission layer 252 which are stacked between the first electrode 210 and the second electrode 290.
The maximum emission wavelength of light emitted from the first emission layer 251 may be different from the maximum emission wavelength of light emitted from the second emission layer 252. For example, the mixed light of the light emitted from the first emission layer 251 and the light emitted from the second emission layer 252 may be white light, but embodiments of the disclosure are not limited thereto.
In one or more embodiments, a hole-transporting region 220 may be located between the first emission layer 251 and the first electrode 210, and an electron-transporting region 270 may be located between the second emission layer 252 and the second electrode 290.
The first emission layer 251 may include a first compound, a second compound, and a third compound, wherein the first compound and the second compound form an exciplex, and the exciplex and the third compound may satisfy Conditions 1-1 and 1-2 above.
The second emission layer 252 may include a first compound, a second compound, and a third compound, wherein the first compound and the second compound form an exciplex, and the exciplex and the third compound may satisfy Conditions 1-1 and 1-2 above.
The first electrode 210, the hole-transporting region 220, and the second electrode 290 illustrated in
The first emission layer 251 and the second emission layer 252 illustrated in
The electron-transporting region 270 illustrated in
As described above, referring to
Explanation of Terms
The term “first-row transition metal of the Periodic Table of Elements” as used herein refers to an element of Period 4 and the d-block of the Periodic Table of Elements, and non-limiting examples thereof include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).
The term “second-row transition metal of the Periodic Table of Elements” as used herein refers to an element of Period 5 and the d-block of the Periodic Table of Elements, and non-limiting examples thereof include yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and cadmium (Cd).
The term “third-row transition metal of the Periodic Table of Elements” as used herein refers to an element of Period 6 and the d-block and the f-block of the Periodic Table of Elements, and non-limiting examples thereof include lanthanum (La), samarium (Sm), europium (Eu), terbium (Tb), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pr), gold (Au), and mercury (Hg).
The term “C1-C60 alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C1-C60 alkylene group” as used herein refers to a divalent group having the same structure as the C1-C60 alkyl group.
The term “C1-C60 alkoxy group” 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 “C2-C60 alkenyl group” as used herein refers to a hydrocarbon group formed by substituting at least one carbon-carbon double bond in the middle or at the terminus of the C2-C60 alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C2-C60 alkenylene group” as used herein refers to a divalent group having the same structure as the C2-C60 alkenyl group.
The term “C2-C60 alkynyl group” as used herein refers to a hydrocarbon group formed by substituting 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 the same structure as the C2-C60 alkynyl group.
The term “C3-C10 cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C3-C10 cycloalkylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkyl group.
The term “C1-C10 heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C1-C10 heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C1-C10 heterocycloalkyl group.
The term “C3-C10 cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C3-C10 cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkenyl group.
The term “C1-C10 heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Examples of the C1-C10 heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C1-C10 heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C1-C10 heterocycloalkenyl group.
The term “C6-C60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C6-C60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Examples of the C6-C60 aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C6-C60 aryl group and the C6-C60 arylene group each include two or more rings, the rings may be fused to each other.
The term “C1-C60 heteroaryl group” as used herein refers to a monovalent group having a heterocarbocyclic aromatic system that has 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 carbocyclic aromatic system that has at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C1-C60 heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C6-C60 heteroaryl group and the C6-C60 heteroarylene group each include two or more rings, the rings may be fused to each other.
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 “monovalent non-aromatic condensed polycyclic group” used herein refers to a monovalent group in which two or more rings are condensed with each other, only carbon is used as a ring-forming atom (for example, the number of carbon atoms may be 8 to 60) and the whole molecule is a non-aromaticity group. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as a monovalent non-aromatic condensed polycyclic group.
The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group having two or more rings condensed to each other, a heteroatom N, O, P, Si, and S, other than carbon atoms (for example, having 1 to 60 carbon atoms), as a ring-forming atom, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic heterocondensed polycyclic group” as used herein refers to a divalent group having the same structure as a monovalent non-aromatic heterocondensed polycyclic group.
The term “C5-C30 carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C5-C30 carbocyclic group may be a monocyclic group or a polycyclic group, and may be a monovalent, divalent, trivalent, tetravalent, pentavalent, or hexavalent group, depending on the formula structure.
The term “C1-C30 heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, at least one heteroatom N, O, Si, P, and S other than 1 to 30 carbon atoms. The C1-C30 heterocyclic group may be a monocyclic group or a polycyclic group, and may be a monovalent, divalent, trivalent, tetravalent, pentavalent, or hexavalent group, depending on the formula structure.
At least one substituent of the substituted C5-C60 carbocyclic group, the substituted C1-C60 heterocyclic group, the substituted C1-C60 alkyl group, the substituted C2-C60 alkenyl group, the substituted C2-C60 alkynyl group, the substituted C1-C60 alkoxy group, the substituted Cr C10 cycloalkyl group, the substituted C1-C10 heterocycloalkyl group, the substituted C3-C10 cycloalkenyl group, the substituted C1-C10 heterocycloalkenyl group, the substituted C6-C60 aryl group, the substituted C6-C60 aryloxy group, the substituted C6-C60 arylthio group, the substituted C1-C60 heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be:
The term “room temperature” used herein refers to a temperature of about 25° C.
The terms “a biphenyl group, a terphenyl group, and a tetraphenyl group” used herein respectively refer to monovalent a group in which two, three, or four phenyl a group which are linked together via a single bond.
The terms “a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, and a cyano-containing tetraphenyl group” used herein respectively refer to a phenyl group, a biphenyl group, a terphenyl group, and a tetraphenyl group, each of which is substituted with at least one cyano group. In “a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, and a cyano-containing tetraphenyl group”, a cyano group may be substituted to any position of the corresponding group, and the “cyano-containing phenyl group, the cyano-containing biphenyl group, the cyano-containing terphenyl group, and the cyano-containing tetraphenyl group” may further include substituents other than a cyano group. For example, a phenyl group substituted with a cyano group, and a phenyl group substituted with a cyano group and a methyl group may all belong to “a cyano-containing phenyl group.”
Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Examples and Examples. However, the organic light-emitting device is not limited thereto. The wording “‘B’ was used instead of ‘A’” used in describing Synthesis Examples means that an amount of ‘A’ used was identical to an amount of ‘B’ used, in terms of a molar equivalent.
The compounds described in Table 7 were vacuum-codeposited on a quartz substrate at weight ratios described in Table 7 and at a vacuum pressure of 10−7 torr to form films having a thickness of 40 nm. With respect to each of the films, the PL spectrum was evaluated at each of room temperature and low temperature (77K) by using FluoTime 300 of PicoQuant Inc. and PLS340, which is a pumping source of PicoQuant Inc., (excitation wavelength=340 nm, and spectrum width=20 nm), such that a triplet excited singlet energy level and a lowest excited triplet energy level were determined.
The compounds described in Tables 8 and 9 were dissolved in toluene having a concentration of 1×10−4 M, and then placed into a quartz cell. Next, the PL spectrum was evaluated at each of room temperature and low temperature (77K) by using FluoTime 300 of PicoQuant Inc. and PLS340, which is a pumping source of PicoQuant Inc., (excitation wavelength=340 nm, and spectrum width=20 nm), such that a triplet excited singlet energy level and a lowest excited triplet energy level were determined.
In an embodiment, a wavelength of a main peak of a PL spectrum obtained for each film was determined, a lowest excited singlet energy level was determined from an onset of the PL spectrum at room temperature, and a lowest excited triplet energy level was determined from an onset of a peak observed only in the PL spectrum at low temperature.
A glass substrate patterned with an ITO electrode having a thickness of 50 nm was ultrasonically cleaned in acetone, isopropyl alcohol, and pure water for 15 minutes each, and then cleaned by UV ozone for 30 minutes.
Next, 40 nm-thick N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine (DNTPD), 10 nm-thick N,N,N′N′-tetra[(1,10-biphenyl)-4-yl]-(1,10-biphenyl)-4,4′-diamine (BPBPA), and 10 nm-thick 3,3-Di(9H-carbazol-9-yl)biphenyl (mCBP) were sequentially deposited on the ITO electrode (anode) of the glass substrate in this stated order.
Next, as an emission layer, HT-HOST A (a first compound), ET-HOST A (a second compound), TADF A (a third compound), and BD1-5 (a fourth compound) were co-deposited at a ratio described in Table 10 to thereby form an emission layer having a thickness of 30 nm.
2,8-bis(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]thiophene (DBFTrz) was deposited on the emission layer to a thickness of 5 nm, 9,10-di(naphthalene-2-yl)anthracen-2-yl-(4,1-phenylene)(1-phenyl-1Hbenzo[d]imidazole (ZADN) was deposited thereon to a thickness of 20 nm, LiF was deposited thereon to a thickness of 1.5 nm, and Al was deposited thereon to a thickness of 200 nm, to thereby completing manufacture of an organic light-emitting device having a structure of ITO (50 nm)/DNTPD (40 nm)/BPBPA (10 nm)/mCBP (10 nm)/emission layer (30 nm)/DBFTrz (5 nm)/ZADN (20 nm)/LiF (1.5 nm)/Al (200 nm).
Organic light-emitting devices were manufactured in the same manner as used in Example 1-1, except that the first compound, the second compound, the third compound, and the fourth compound were each used as shown in Table 10 to form an emission layer.
With respect to each of the organic light-emitting devices manufactured in Examples 1-1 to 1-6 and Comparative Example 1-1, external quantum efficiency (EQE), maximum EQE, and lifespan were evaluated, and results are shown in Table 11. In this regard, the lifespan refers to a time (T95) that is taken for the luminance to become 95% compared to the initial luminance of 100% at 1,000 nit.
Referring to Table 11, it may be confirmed that each of the efficiency and the lifespan of the organic light-emitting devices of Examples 1-1 to 1-6 are improved.
The organic light-emitting device may have long lifespan.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
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