Patent Application
20240206312
This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0150965, filed on Nov. 11, 2022, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the entire content of which is incorporated by reference herein.
The present subject matter relates to an organometallic compound, an organic light-emitting device including the same, and an electronic apparatus including the organic light-emitting device.
Organic light-emitting devices (OLEDs) are self-emissive devices, which have improved characteristics in terms of viewing angles, response time, luminance, driving voltage, and response speed. In addition, OLEDs can produce full-color images.
In an example, an organic light-emitting device includes an anode, a cathode, and an organic layer that is arranged between the anode and the cathode, and includes an emission layer. A hole transport region may be arranged between the anode and the emission layer, and an electron transport region may be arranged between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons may recombine in the emission layer to produce excitons. The excitons may then transition from an excited state to a ground state, thereby generating light.
Provided are an organometallic compound, an organic light-emitting device including the same, and an electronic apparatus including the organic light-emitting device.
Additional aspects will be set forth in part in the detailed description that follows and, in part, will be apparent from the detailed description, or may be learned by practice of the presented exemplary embodiments herein.
According to an aspect, provided is an organometallic compound represented by Formula 1:
M1(L1)n1(L2)n2 Formula 1
wherein, in Formula 1,
wherein, in Formulae 1A and 1B,
According to another aspect, an organic light-emitting device includes a first electrode, a second electrode, and an organic layer arranged between the first electrode and the second electrode, wherein the organic layer includes an emission layer, and wherein the organic layer further includes at least one of the organometallic compounds.
At least one of the organometallic compounds may be included in the emission layer of the organic layer, and the at least one organometallic compound included in the emission layer may act as a dopant.
According to another aspect, an electronic apparatus includes the organic light-emitting device.
The above and other aspects, features, and advantages of certain exemplary embodiments will be more apparent from the following detailed description taken in conjunction with the FIGURE, which is a schematic cross-sectional view of an organic light-emitting device according to one or more embodiments.
Reference will now be made in further detail to exemplary embodiments, examples of which are illustrated in the accompanying drawing, wherein like reference numerals refer to like elements throughout. In this regard, the present exemplary embodiments may have different forms and should not be construed as being limited to the detailed descriptions set forth herein. Accordingly, the exemplary embodiments are merely described in further detail below, and by referring to the FIGURE, to explain certain aspects and features. 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.
The terminology used herein is for the purpose of describing one or more exemplary embodiments only 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. The term “or” means “and/or.” It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
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 of the present embodiments.
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.
It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with 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.
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 general inventive concept 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.
“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%, 5% of the stated value.
Hereinafter, a work function or a highest occupied molecular orbital (HOMO) energy level is expressed as an absolute value from a vacuum level. In addition, when the work function or the HOMO energy level is referred to be “deep,” “high” or “large,” the work function or the HOMO energy level has a large absolute value based on “0 electron Volts (eV)” of the vacuum level, while when the work function or the HOMO energy level is referred to be “shallow,” “low,” or “small,” the work function or HOMO energy level has a small absolute value based on “0 eV” of the vacuum level.
An aspect provides an organometallic compound represented by Formula 1:
M1(L1)n1(L2)n2. Formula 1
wherein M1 in Formula 1 is a transition metal.
In one or more embodiments, M1 in Formula 1 may be a first-row transition metal of the Periodic Table of Elements, a second-row transition metal of the Periodic Table of Elements, or a third-row transition metal of the Periodic Table of Elements.
In one or more embodiments, M1 may be iridium, platinum, osmium, palladium, gold, titanium, zirconium, hafnium, europium, terbium, thulium, or rhodium.
For example, M1 may be iridium, osmium, platinum, palladium, or gold.
In one or more embodiments, M1 may be iridium.
n1 and n2 in Formula 1 are each independently 1 or 2.
In one or more embodiments, a sum of n1 and n2 may be 3.
For example, n1 may be 2, and n2 may be 1.
L1 in Formula 1 is a ligand represented by Formula 1A:
X1 and X2 in Formula 1A are each independently C or N.
A bond between M1 and X1 in Formula 1A may be a covalent bond or a coordinate bond.
A bond between M1 and X2 in Formula 1A may be a covalent bond or a coordinate bond.
In one or more embodiments, X1 may be N, X2 may be C, a bond between X1 and M1 may be a coordinate bond, and a bond between X2 and M1 may be a covalent bond.
Ring CY2 in Formula 1A is a C5-C30 carbocyclic group or a C1-C30 heterocyclic group.
In one or more embodiments, ring CY2 may be a first ring, a second ring, a condensed ring group in which two or more first rings are condensed with each other, a condensed ring group in which two or more second rings are condensed with each other, or a condensed ring group in which at least one first ring is condensed with at least one second ring,
In one or more embodiments, ring CY2 may be a benzene group, a naphthalene group, a 1,2,3,4-tetrahydronaphthalene group, a phenanthrene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a benzofuran group, a benzothiophene group, a fluorene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, or an azadibenzosilole group. For example, ring CY2 may be a benzene group, a naphthalene group, or a pyridine group.
In Formula 1A, two or more of R13 to R16 are linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group.
In Formula 1A, two or more of R2 are optionally linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group.
In one or more embodiments, a moiety represented by
in Formula 1A may be a group represented by one of Formulae 1-1 to 1-3:
In Formulae 1-1 to 1-3,
In one or more embodiments, in Formula 1-1, at least one of R1 in the number of b1 may not be hydrogen.
In one or more embodiments, at least one of R13 and R14 in Formula 1-2 may not be hydrogen.
In one or more embodiments, a moiety represented by
in Formula 1A may be a group represented by one of Formulae 2-1 to 2-16:
In Formulae 2-1 to 2-16,
X3 and X4 in Formula 1B are each independently C or N.
A bond between M1 and X3 in Formula 1B may be a covalent bond or a coordinate bond.
A bond between M1 and Y1 or X4 in Formula 1B may be a covalent bond or a coordinate bond.
In one or more embodiments, X3 may be N, X4 may be C, a bond between X3 and M1 may be a coordinate bond, and a bond between Y1 or X4 and M1 may be a covalent bond.
Y1 in Formula 1B is O, S, Se, C(R5)(R6), N(R7), or Si(R8)(R9), wherein R5 to R9 are as defined herein.
For example, Y1 may be O, S, or Se.
Ring CY3 in Formula 1B is a 5-membered heterocyclic group, a 5-membered heterocyclic group condensed with a C5-C30 carbocyclic group, or a 5-membered heterocyclic group condensed with a C1-C30 heterocyclic group.
In one or more embodiments, ring CY3 may include at least one nitrogen atom.
Ring CY4 in Formula 1B is a C5-C30 carbocyclic group or a C1-C30 heterocyclic group.
In one or more embodiments, ring CY3 may be a first ring, a condensed ring group in which two or more first rings are condensed with each other, or a condensed ring group in which at least one first ring is condensed with at least one second ring,
In one or more embodiments, ring CY3 may be an imidazole group or a benzimidazole group.
In one or more embodiments, ring CY4 may be a benzene group, a naphthalene group, a 1,2,3,4-tetrahydronaphthalene group, a phenanthrene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a benzofuran group, a benzothiophene group, a fluorene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, or an azadibenzosilole group.
In one or more embodiments, a moiety represented by
in Formula 1B may be a group represented by Formula 3-1 or 3-2:
In Formulae 3-1 and 3-2,
In one or more embodiments, L30 may be a single bond, a C1-C20 alkylene group unsubstituted or substituted with at least one R10a, a C6-C30 arylene group unsubstituted or substituted with at least one R10a, or a C1-C30 heteroarylene group unsubstituted or substituted with at least one R10a, and
R10a may be as defined herein in connection with R2.
In one or more embodiments, a moiety represented by
in Formula 1B may be a group represented by one of Formulae 4-1 to 4-16:
In Formulae 4-1 to 4-16,
R2 to R9 and R11 to R16 in Formulae 1A and 1B are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF5, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C2-C60 alkenyl group, a substituted or unsubstituted C2-C60 alkynyl group, a substituted or unsubstituted C1-C60 alkoxy group, a substituted or unsubstituted C1-C60 alkylthio group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C1-C10 heterocycloalkyl group, a substituted or unsubstituted C3-C10 cycloalkenyl group, a substituted or unsubstituted C1-C10 heterocycloalkenyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C7-C60 alkyl aryl group, a substituted or unsubstituted C7-C60 aryl alkyl group, a substituted or unsubstituted C6-C60 aryloxy group, a substituted or unsubstituted C6-C60 arylthio group, a substituted or unsubstituted C1-C60 heteroaryl group, a substituted or unsubstituted C2-C60 alkyl heteroaryl group, a substituted or unsubstituted C2-C60 heteroaryl alkyl group, a substituted or unsubstituted C1-C60 heteroaryloxy group, a substituted or unsubstituted C1-C60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q1)(Q2)(Q3), —Ge(Q1)(Q2)(Q3), —N(Q4)(Q5), —B(Q6)(Q7), —P(Q8)(Q9), or —P(═O)(Q8)(Q9).
In one or more embodiments, R2 to R9 and R11 to R16 may each independently be:
In one or more embodiments, R2 to R9 and R11 to R16 may each independently be:
In Formulae 9-1 to 9-39, 9-44 to 9-61, 9-201 to 9-237, 10-1 to 10-129, and 10-201 to 10-350, * may indicate a binding site to a neighboring atom, “Ph” may be a phenyl group, “TMS” may be a trimethylsilyl group, and “TMG” may be a trimethylgermyl group.
As noted above, two or more of R13 to R16 in Formula 1A are linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group.
For example, in Formula 1A, i) R13 and R14 may be linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group, ii) R15 and R16 may be linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group, or iii) R14 and R15 may be linked to each other to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group.
In one or more embodiments, a ring formed by linking two or more of R13 to R16 to each other may be a benzene group, a naphthalene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a quinoline group, or an isoquinoline group.
b2 to b4 in Formulae 1A and 1B are each independently an integer from 1 to 10.
* and *′ in Formulae 1A and 1B each indicates a binding site to M1.
In one or more embodiments, L2 may be a ligand represented by Formula 1B-1 or 1B-2:
In Formulae 1B-1 and 1B-2,
In one or more embodiments, L30 may be a single bond, a C1-C20 alkylene group unsubstituted or substituted with at least one R10a, a C6-C30 arylene group unsubstituted or substituted with at least one R10a, or a C1-C30 heteroarylene group unsubstituted or substituted with at least one R10a, and
R10a may be as defined herein in connection with R2.
In one or more embodiments, the organometallic compound may be represented by one of Formulae 5-1 to 5-6:
In Formulae 5-1 to 5-6,
In one or more embodiments, the organometallic compound may be represented by one of Compounds 1 to 63:
In one or more embodiments, the organometallic compound may be electrically neutral.
The organometallic compound represented by Formula 1 includes a ligand represented by Formula 1A and a ligand represented by Formula 1B. Due to this structure, the organometallic compound represented by Formula 1 may have excellent luminescence characteristics, and in particular, may have such characteristics suitable for use as a luminescent material with high color purity by controlling the emission wavelength range.
In addition, since the organometallic compound represented by Formula 1 has excellent electrical mobility, an electronic device, for example, an organic light-emitting device, including at least one of the organometallic compounds represented by Formula 1 may exhibit a low driving voltage, a high efficiency, and a low roll-off ratio.
A highest occupied molecular orbital (HOMO) energy level, a lowest unoccupied molecular orbital (LUMO) energy level, a singlet (Si) energy level, and a triplet (Ti) energy level of selected organometallic compounds represented by Formula 1 were calculated using a density functional theory (DFT) method of the Gaussian 09 program with the molecular structure optimized at the B3LYP level, and results thereof are shown in Table 1. The energy levels are expressed in electron volts (eV).
From Table 1, it was confirmed that the organometallic compounds represented by Formula 1 had such electric characteristics that are suitable for use as a dopant for an electronic device, for example, an organic light-emitting device.
In one or more embodiments, a full width at half maximum (FWHM) of an emission peak of an emission spectrum or an electroluminescence spectrum of the organometallic compound represented by Formula 1 may be about 60 nanometers (nm) or less, about 59 nm or less, about 58 nm or less, about 57 nm or less, about 56 nm or less, or about 55 nm or less.
In one or more embodiments, a maximum emission wavelength (emission peak wavelength, λmax) of the emission peak of the emission spectrum or the electroluminescence spectrum of the organometallic compound represented by Formula 1 may be about 590 nm to about 650 nm. For example, the maximum emission wavelength of the emission peak of the emission spectrum or the electroluminescence spectrum of the organometallic compound represented by Formula 1 may be about 600 nm to about 650 nm, about 590 nm to about 640 nm, or about 600 nm to about 640 nm.
Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art and by referring to Synthesis Examples provided herein.
The organometallic compound represented by Formula 1 may be suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect provides an organic light-emitting device including a first electrode; a second electrode; and an organic layer that is arranged between the first electrode and the second electrode, wherein the organic layer includes an emission layer, and wherein the organic layer further includes at least one of the organometallic compounds represented by Formula 1.
Since the organic light-emitting device has an organic layer including at least one of the organometallic compounds represented by Formula 1 as described herein, the organic light-emitting device may have excellent characteristics in terms of drive voltage, current efficiency, external quantum efficiency, roll-off ratio, and/or lifespan.
The organometallic compound represented by Formula 1 may be used between a pair of electrodes of the organic light-emitting device. For example, at least one of the organometallic compounds represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, an amount of the at least one organometallic compound represented by Formula 1 in the emission layer may be less than an amount of the host in the emission layer, based on weight). In one or more embodiment, an amount of the host in the emission layer may be greater than an amount of the at least one organometallic compound represented by Formula 1 in the emission layer, based on weight.
In one or more embodiments, the emission layer may emit a red light. For example, the emission layer may emit a red light having a maximum emission wavelength of about 590 nm to about 650 nm. For example, the emission layer may emit a red light having a maximum emission wavelength of about 600 nm to about 650 nm, about 590 nm to about 640 nm, or about 600 nm to about 640 nm.
The expression “(an organic layer) includes at least one of the organometallic compounds represented by Formula 1” as used herein may include a case in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and a case in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”
For example, the organic layer may include, as the at least one organometallic compound represented by Formula 1, only Compound 1. In this regard, Compound 1 may be present in the emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the at least one organometallic compound represented by Formula 1, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be present in an identical layer (e.g., both Compound 1 and Compound 2 may be present in the emission layer).
The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode. In one or more embodiments, the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.
For example, in the organic light-emitting device, the first electrode may be an anode, the second electrode may be a cathode, and the organic layer may further include a hole transport region arranged between the first electrode and the emission layer, and an electron transport region arranged between the emission layer and the second electrode, wherein the hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or a combination thereof, and the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof.
The term “organic layer” as used herein refers to a single layer and/or a plurality of layers that are arranged between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.
The FIGURE is a schematic cross-sectional view of an organic light-emitting device 10 according to one or more embodiments. Hereinafter, the structure and manufacturing method of the organic light-emitting device 10 according to one or more embodiments will be described in further detail with reference to the FIGURE, but embodiments are not limited thereto. The organic light-emitting device 10 may include a first electrode 11, an organic layer 15, and a second electrode 19, which are sequentially stacked in this stated order.
A substrate may be additionally arranged under the first electrode 11 or above the second electrode 19. For use as the substrate, any suitable substrate that is used in organic light-emitting devices available in the art may be used, and, for example, 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/or water resistance.
The first electrode 11 may be, for example, 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 selected from materials 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. The material for forming the first electrode 11 may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), or zinc oxide (ZnO). In one or more embodiments, the material for forming the first electrode 11 may be a metal, such as magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag).
The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 11 may have a three-layered structure of ITO/Ag/ITO, but embodiments are not limited thereto.
The organic layer 15 may be arranged on the first electrode 11.
The organic layer 15 may include a hole transport region, an emission layer, an electron transport region, or a combination thereof.
The hole transport region may be arranged between the first electrode 11 and the emission layer.
The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or a combination thereof.
The hole transport region may include only a hole injection layer or only a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein, for each structure, respective layers are sequentially stacked in the stated orders from the first electrode 11.
When the hole transport region includes a hole injection layer, the hole injection layer may be formed on the first electrode 11 by using one or more suitable methods, such as vacuum deposition, spin coating, casting, and/or Langmuir-Blodgett (LB) deposition, but embodiments are not limited thereto.
When the hole injection layer is formed by vacuum deposition, the deposition conditions may vary according to a material that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100° C. to about 500° C., a vacuum pressure of about 10−8 torr to about 10−3 torr, and a deposition rate of about 0.01 angstroms per second (Å/sec) to about 100 Å/sec, but embodiments are not limited thereto.
When the hole injection layer is formed by spin coating, the coating conditions may vary according to a material that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the coating conditions may include a coating speed of about 2,000 revolutions per minute (rpm) to about 5,000 rpm and a heat treatment temperature for removing a solvent after coating of about 80° C. to about 200° C., but embodiments are not limited thereto.
Conditions for forming the hole transport layer and the electron blocking layer may be similar to or the same as the conditions for forming the hole injection layer, although conditions may vary according to a material that is used to form the hole transport layer and/or the electron blocking layer, and the structure and thermal characteristics of the hole transport layer and/or the electron blocking layer.
The hole transport region may include, for example, at least one of 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4′,4″-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), β-NPB, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), spiro-TPD, spiro-NPB, methylated NPB, 4,4′-cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), 4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (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), a compound represented by Formula 201, or a compound represented by Formula 202, but embodiments are not limited thereto:
Ar101 and Ar102 in Formula 201 may each independently be:
xa and xb in Formula 201 may each independently be an integer from 0 to 5, or may each independently be 0, 1, or 2. For example, xa may be 1, and xb may be 0, but embodiments are not limited thereto.
R101 to R108, R111 to R119, and R121 to R124 in Formulae 201 and 202 may each independently be:
R109 in Formula 201 may be:
In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments are not limited thereto:
R101, R111, R112, and R109 in Formula 201A may each be as defined herein.
For example, the compound represented by Formula 201 and the compound represented by Formula 202 may include at least one of Compounds HT1 to HT20, but embodiments are not limited thereto:
A thickness of the hole transport region may be about 100 angstroms (Å) to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, a thickness of the hole injection layer may be about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. Without wishing to be bound to theory, when the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.
The hole transport region may further include, in addition to the materials described above, a charge-generation material for improving conductive properties. The charge-generation material may be homogeneously dispersed in the hole transport region or non-homogeneously dispersed in the hole transport region.
The charge-generation material may be, for example, a p-dopant. The p-dopant may be one of a quinone derivative, a metal oxide, or a cyano group-containing compound, but embodiments are not limited thereto. For example, non-limiting examples of the p-dopant may include a quinone derivative, such as tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ), 1,3,4,5,7,8-hexafluorotetracyanonaphthoquinodimethane (F6-TCNQ), or the like; a metal oxide, such as a tungsten oxide, a molybdenum oxide, or the like; or a cyano group-containing compound, such as Compound HT-D1 or Compound F12, but embodiments are not limited thereto:
The hole transport region may further include a buffer layer.
The buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer to improve the efficiency of an organic light-emitting device.
The emission layer may be formed on the hole transport region by using one or more suitable methods, such as vacuum deposition, spin coating, casting, and/or LB deposition, but embodiments are not limited thereto. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer, though the deposition or coating conditions may vary according to a material that is used to form the emission layer.
When the hole transport region includes an electron blocking layer, a material for forming the electron blocking layer may be selected from materials for the hole transport region described herein and host materials to be described herein, but embodiments are not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for forming the electron blocking layer may be mCP, which is described herein.
The emission layer may include a host and a dopant, and the dopant may include at least one of the organometallic compounds represented by Formula 1.
The host may include at least one of 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), 9,10-di(naphthalene-2-yl)anthracene (ADN) (also referred to as “DNA”), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CDBP), 1,3,5-tris(carbazole-9-yl)benzene (tCP), 1,3-bis(N-carbazolyl)benzene (mCP), Compound H50, or Compound H51, but embodiments are not limited thereto:
In one or more embodiments, the host may include a compound represented by Formula 301, but embodiments are not limited thereto:
Ar111 and Ar112 in Formula 301 may each independently be:
Ar113 to Ar116 in Formula 301 may each independently be:
g, h, i, and j in Formula 301 may each independently be an integer from 0 to 4, and for example, g, h, i, and j in Formula 301 may each independently be 0, 1, or 2.
Ar113 to Ar116 in Formula 301 may each independently be:
but embodiments are not limited thereto.
In one or more embodiments, the host may include a compound represented by Formula 302, but embodiments are not limited thereto:
Ar122 to Ar125 in Formula 302 may each be as defined herein in connection with Ar113 in Formula 301.
Ar126 and Ar127 in Formula 302 may each independently be a C1-C10 alkyl group (for example, a methyl group, an ethyl group, a propyl group, or the like).
k and l in Formula 302 may each independently be an integer from 0 to 4. For example, k and l may each independently be 0, 1, or 2.
When the organic light-emitting device 10 is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light, and various modifications are possible.
When the emission layer includes a host and a dopant, an amount of the dopant may be about 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the host, but embodiments are not limited thereto.
A thickness of the emission layer may be about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. Without wishing to be bound to theory, when the thickness of the emission layer is within these ranges, excellent luminescence characteristics may be obtained without a substantial increase in driving voltage.
Next, the electron transport region may be arranged on the emission layer.
The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof.
For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure, or an electron transport layer/electron injection layer structure, but embodiments are not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.
Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be similar to or the same as the conditions for forming the hole injection layer.
When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), or bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), but embodiments are not limited thereto:
A thickness of the hole blocking layer may be about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. Without wishing to be bound to theory, when the thickness of the hole blocking layer is within these ranges, excellent hole blocking characteristics may be obtained without a substantial increase in driving voltage.
The electron transport layer may further include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), tris(8-hydroxy-quinolinato)aluminum (Alq3), bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), or 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ):
In one or more embodiments, the electron transport layer may include at least one of Compounds ET1 to ET25, but embodiments are not limited thereto:
A thickness of the electron transport layer may be about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. Without wishing to be bound to theory, when the thickness of the electron transport layer is within these ranges, satisfactory electron transporting characteristics may be obtained without a substantial increase in driving voltage.
The electron transport layer may further include, in addition to the materials described above, a metal-containing material.
The metal-containing material may include a Li complex. The Li complex may include, for example, at least one of Compound ET-D1 (lithium 8-hydroxyquinolate, LiQ) or ET-D2, but embodiments are not limited thereto:
The electron transport region may include an electron injection layer that facilitates electron injection from the second electrode 19.
The electron injection layer may include at least one of LiF, NaCl, CsF, Li2O, BaO, or a combination thereof, but embodiments are not limited thereto.
A thickness of the electron injection layer may be about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. Without wishing to be bound to theory, when the thickness of the electron injection layer is within these ranges, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.
The second electrode 19 may be arranged on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be a metal, an alloy, an electrically conductive compound, or a combination thereof, which has a relatively low work function. For example, lithium (L1), magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as the material for forming the second electrode 19. In one or more embodiments, to manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode 19.
Hereinbefore, the organic light-emitting device 10 has been described in further detail with reference to the FIGURE, but embodiments are not limited thereto.
Another aspect of the disclosure provides a diagnostic composition including at least one of the organometallic compounds represented by Formula 1.
Since the organometallic compound represented by Formula 1 provides a high luminescence efficiency, the diagnostic composition including at least one of the organometallic compounds represented by Formula 1 may have a high diagnostic efficiency.
The diagnostic composition may be used in various applications, such as a diagnosis kit, a diagnosis reagent, a biosensor, a biomarker, or the like, or a combination thereof.
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 non-limiting 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, a hexyl group, or the like. 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” as used herein refers to a monovalent group represented by —OA101 (wherein A101 is the C1-C60 alkyl group), and non-limiting examples thereof include a methoxy group, an ethoxy group, an isopropyloxy group, or the like.
The term “C1-C60 alkylthio group” used herein refers to a monovalent group represented by —SA101′ (wherein A101′ is the C1-C60 alkyl 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 non-limiting examples thereof include an ethenyl group, a propenyl group, a butenyl group, or the like. 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 non-limiting examples thereof include an ethynyl group, a propynyl group, or the like. The term “C2-C60 alkynylene group” as used herein refers to a divalent group having the same structure as the C2-C60 alkynyl group.
The term “C3-C10 cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, or the like. The term “C3-C10 cycloalkylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkyl group.
The term “C1-C10 heterocycloalkyl group” as used herein refers to a monovalent cyclic group having at least one heteroatom selected from N, O, P, Si, S, Se, Ge, and B as a ring-forming atom and 1 to 10 carbon atoms as ring-forming atom(s), and non-limiting examples thereof include a tetrahydrofuranyl group, a tetrahydrothiophenyl group, or the like. 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 cyclic 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, a cycloheptenyl group, or the like. The term “C3-C10 cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C3-C10 cycloalkenyl group.
The term “C1-C10 heterocycloalkenyl group” as used herein refers to a monovalent cyclic group that has at least one heteroatom selected from N, O, P, Si, S, Se, Ge, and B as a ring-forming atom, 1 to 10 carbon atoms as ring-forming atom(s), and at least one double bond in the ring thereof. Non-limiting examples of the C1-C10 heterocycloalkenyl group include a 2,3-dihydrofuranyl group, a 2,3-dihydrothiophenyl group, or the like. 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 ring 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 ring system having 6 to 60 carbon atoms. Non-limiting examples of the C6-C60 aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, a chrysenyl group, or the like. When the C6-C60 aryl group and the C6-C60 arylene group each include two or more rings, the two or more rings may be fused to each other.
The term “C7-C60 alkyl aryl group” as used herein refers to a C6-C60 aryl group substituted with at least one C1-C60 alkyl group. The term “C7-C60 aryl alkyl group” as used herein refers to a C1-C60 alkyl group substituted with at least one C6-C60 aryl group.
The term “C1-C60 heteroaryl group” as used herein refers to a monovalent group having a cyclic aromatic ring system that has at least one heteroatom selected from N, O, P, Si, S, Se, Ge, and B as a ring-forming atom, and 1 to 60 carbon atoms as ring-forming atom(s), and the term “C1-C60 heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic ring system that has at least one heteroatom selected from N, O, P, Si, S, Se, Ge, and B as a ring-forming atom, and 1 to 60 carbon atoms as ring-forming atom(s). Non-limiting 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, an isoquinolinyl group, or the like. When the C1-C60 heteroaryl group and the C1-C60 heteroarylene group each include two or more rings, the two or more rings may be fused to each other.
The term “C2-C60 alkyl heteroaryl group” as used herein refers to a C1-C60 heteroaryl group substituted with at least one C1-C60 alkyl group. The term “C2-C60 heteroaryl alkyl group” as used herein refers to a C1-C60 alkyl group substituted with at least one C1-C60 heteroaryl group.
The term “C6-C60 aryloxy group” as used herein refers to —OA102 (wherein A102 is the C6-C60 aryl group), and the term “C6-C60 arylthio group” as used herein refers to —SA103 (wherein A103 is the C6-C60 aryl group).
The term “C1-C60 heteroaryloxy group” as used herein refers to —OA104 (wherein A104 is the C1-C60 heteroaryl group), and the term “C1-C60 heteroarylthio group” as used herein refers to —SA105 (wherein A105 is the C1-C60 heteroaryl group).
The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group (e.g., having 8 to 60 carbon atoms) that has two or more rings condensed with each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group or the like. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.
The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (e.g., having 1 to 60 carbon atoms) that has two or more rings condensed with each other, a heteroatom selected from B, N, O, P, Si, and S, other than 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 and the like. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.
The term “C5-C30 carbocyclic group” as used herein refers to a saturated or unsaturated ring group having 5 to 30 carbon atoms only as ring-forming atoms. The C5-C30 carbocyclic group may be a monocyclic group or a polycyclic group.
The term “C1-C30 heterocyclic group” as used herein refers to a saturated or unsaturated ring group having 1 to 30 carbon atoms and at least one heteroatom selected from N, O, P, Si, S, Se, Ge, and B as ring-forming atoms. The C1-C30 heterocyclic group may be a monocyclic group or a polycyclic group.
At least one substituent of the substituted C5-C30 carbocyclic group, the substituted C1-C30 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 C1-C60 alkylthio group, the substituted C3-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 C7-C60 alkyl aryl group, the substituted C7-C60 aryl alkyl group, the substituted C6-C60 aryloxy group, the substituted C6-C60 arylthio group, the substituted C1-C60 heteroaryl group, the substituted C2-C60 alkyl heteroaryl group, the substituted C2-C60 heteroaryl alkyl group, the substituted C1-C60 heteroaryloxy group, the substituted C1-C60 heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be:
Hereinafter, organometallic compounds represented by Formula 1 and organic light-emitting devices according to exemplary embodiments will be described in further detail with reference to Synthesis Examples and Examples, but the disclosure is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of B used was identical to an amount of A used based on molar equivalence.
In a nitrogen environment, 4-chloro-8-methylbenzo[f]isoquinoline (1.00 gram (g), 4.39 millimoles (mmol)) and 2-(3,5-dimethylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxoborolane (1.12 g, 4.83 mmol) were dissolved in 90 milliliters (mL) of 1,4-dioxane. Then, a separate solution was prepared using potassium carbonate (K2CO3) (1.40 g, 10.1 mmol) and 35 mL of deionized (DI) water, which was then added to the reaction mixture. Then, a palladium catalyst (tetrakis(triphenylphosphine)palladium(0), Pd(PPh3)4) (0.25 g, 0.22 mmol) was added to the reaction mixture. Subsequently, the resultant reaction mixture was stirred and heated under reflux at 110° C. After allowing the contents to cool to room temperature, an extraction process was performed thereon, and the solvent was removed under a reduced pressure. The solid thus obtained was purified by column chromatography (eluents: ethyl acetate (EA) and n-hexane) to obtain 1.26 g (yield of 96%) of Compound 1A (4-(3,5-dimethylphenyl)-8-methylbenzo[f]isoquinoline). The obtained compound was identified by high resolution mass spectrometry using matrix assisted laser desorption ionization (HRMS (MALDI)) and high-performance liquid chromatography (HPLC) analysis.
HRMS (MALDI) calculated for C22H19N: m/z: 297.40; found: 298.31.
Compound 1A (1.24 g, 4.17 mmol) and iridium chloride trihydrate (0.7 g, 1.99 mmol) were mixed with 30 mL of 2-ethoxyethanol and 10 mL of DI water. Then, the reaction mixture was stirred and heated under reflux for 24 hours. Then, the temperature was allowed to lower to room temperature. The solid thus obtained was separated by filtration, washed sufficiently with water, methanol, and hexane, in this stated order, and then dried in a vacuum oven to obtain 1.33 g (yield of 81%) of Compound 1B. Compound 1B obtained was used in the next reaction without an additional purification process.
2-(1-methyl-1H-benzo[d]imidazole-2-yl)phenol (0.44 g, 1.98 mmol) and potassium carbonate (K2CO3) (0.27 g, 1.98 mmol) were added to Compound 1B (1.3 g, 0.79 mmol) and then mixed with 20 mL of 2-ethoxyethanol, and the reaction mixture was stirred for 18 hours at room temperature. After an extraction process was performed thereon, the solid thus obtained was purified by column chromatography (eluents: methylene chloride (MC) and hexane) to obtain 1.04 g (yield of 65%) of Compound 1. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calculated for C58H47IrN4O: m/z: 1008.26; found: 1008.95.
1.01 g (yield of 63%) of Compound 2 was obtained in a similar manner as in Synthesis Example 1, except that, in synthesizing Compound 1, 4-chloro-7-methylbenzo[f]isoquinoline was used instead of 4-chloro-8-methylbenzo[f]isoquinoline. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calculated for C58H47IrN4O: m/z: 1008.26; found: 1009.03.
0.99 g (yield of 62%) of Compound 4 was obtained in a similar manner as in Synthesis Example 1, except that, in synthesizing Compound 1, 4-chloro-7-fluorobenzo[f]isoquinoline was used instead of 4-chloro-8-methylbenzo[f]isoquinoline. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calcd for C56H41F2IrN4O: m/z: 1016.18 Found: 1017.04
As an anode, an ITO-patterned glass substrate was cut to a size of 50 millimeters (mm)×50 mm×0.5 mm, sonicated with isopropyl alcohol and DI water, each for 5 minutes, and then cleaned by irradiation with ultraviolet rays and exposure of ozone for 30 minutes. The resultant patterned glass substrate was loaded onto a vacuum deposition apparatus.
Compound HT3 and F12-P-Dopant were co-deposited by vacuum on the anode at a weight ratio of 98:2 to form a hole injection layer having a thickness of 100 Å, and Compound HT3 was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 1,600 Å.
Then, Compound RH3 (host) and Compound 1 (dopant) were co-deposited by vacuum on the hole transport layer at a weight ratio of 97:3 to form an emission layer having a thickness of 400 Å.
Subsequently, Compound ETL and Liq-N-Dopant were co-deposited by vacuum on the emission layer at a volume ratio of 50:50 to form an electron transport layer having a thickness of 350 Å, Liq-N-Dopant was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of 1,000 Å, thereby completing the manufacture of an organic light-emitting device.
Organic light-emitting devices were manufactured in a similar manner as in Example 1, except that, in forming an emission layer, compounds shown in Table 2 were each used as a dopant compound instead of Compound 1.
The driving voltage (Volts, V), roll-off ratio (%), maximum emission wavelength (λmax, nm), FWHM (nm), and maximum value of external quantum efficiency (Max EQE) were evaluated for each of the organic light-emitting devices manufactured in Examples 1 to 3 and Comparative Examples 1 and 2, and results thereof are shown in Table 2. A current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1,000A) were used as apparatuses for evaluation, and the roll-off ratio has determined according to Equation 2.
Roll-off ratio={1−(efficiency (at 18,000 cd/m2)/maximum luminescence efficiency)}×100% Equation 2
From Table 2, it was confirmed that the organic light-emitting devices of Examples 1 to 3 had characteristics of a low driving voltage, a low roll-off ratio, a narrow FWHM, and a high external quantum efficiency.
In addition, it was confirmed that the organic light-emitting devices of Examples 1 to 3 had a lower driving voltage, a lower roll-off ratio, an equivalent or narrower FWHM, and a higher external quantum efficiency than the organic light-emitting devices of Comparative Examples 1 and 2.
As described herein, the organometallic compounds represented by Formula 1 may have excellent electrical characteristics, and thus, an electronic device, for example, an organic light-emitting device, including at least one of the organometallic compounds represented by Formula 1 may have characteristics of a low driving voltage, a high external quantum efficiency, and a low roll-off ratio. Accordingly, by using the organometallic compounds represented by Formula 1, a high-quality organic light-emitting device may be realized.
It should be understood that exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should typically be considered as available for other similar features or aspects in other exemplary embodiments. While one or more exemplary embodiments have been described with reference to the FIGURE, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0150965 | Nov 2022 | KR | national |
