Patent Application
20240074300
This application is based on and claims priority to Korean Patent Application No. 10-2022-0097566, filed on Aug. 4, 2022, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which is incorporated by reference herein in its entirety.
The present subject matter relates to organometallic compounds, 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, OLDEs may produce full-color images.
In a typical 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. These excitons may transition from an excited state to a ground state, thereby generating light.
Provided are organometallic compounds, 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:
M
1(L1)n1(L2)n2 Formula 1
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 compound.
The organometallic compound may be included in the emission layer of the organic layer, and the organometallic compound included in the emission layer may act as a dopant.
According to still 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. 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.
According to an aspect, provided is an organometallic compound represented by Formula 1:
M
1(L1)n1(L2)n2 Formula 1
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, palladium, gold, osmium, 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 1 Å:
A bond between M1 and X1 in Formula 1 Å may be a covalent bond or a coordinate bond.
A bond between M1 and X2 in Formula 1 Å 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 1 Å is a C5-C30 carbocyclic group or a C1-C30 heterocyclic group.
In one or more embodiments, ring CY2 may be i) a first ring, ii) a second ring, iii) a condensed ring group in which two or more first rings are condensed with each other, iv) a condensed ring group in which two or more second rings are condensed with each other, or v) 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 or a naphthalene group.
In one or more embodiments, a moiety represented by
In one or more embodiments, T12 and T13 may each independently be a C1-C20 alkyl group substituted with at least one R10a, a C3-C1 cycloalkyl group substituted with at least one R10a, a C1-C1 heterocycloalkyl group substituted with at least one R10a, a C6-C60 aryl group substituted with at least one R10a, a C7-C60 alkyl aryl group substituted with at least one R10a, a C7-C60 aryl alkyl group substituted with at least one R10a, a C1-C60 heteroaryl group substituted with at least one R10a, a C2-C60 alkyl heteroaryl group substituted with at least one R10a, or a C2-C60 heteroaryl alkyl group substituted with at least one R10a.
For example, T12 and T13 may each be a C1-C1 alkyl group substituted with at least one deuterium.
In one or more embodiments, a moiety represented by
R2, R11, and R14 in Formula 1 Å 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-C1 heterocycloalkyl group, a substituted or unsubstituted C3-C10 cycloalkenyl group, a substituted or unsubstituted C2-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).
R12 and R13 in Formula 1 Å 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-C1 cycloalkyl group, a substituted or unsubstituted C1-C1 heterocycloalkyl group, a substituted or unsubstituted C3-C1 cycloalkenyl group, a substituted or unsubstituted C2-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, —N(Q4)(Q5), —B(Q6)(Q7), —P(Q8)(Q9), or —P(═O)(Q8)(Q9).
In one or more embodiments, R2, R11, and R14 in Formula 1 Å may each independently be:
In one or more embodiments, R2, R11, and R14 may each independently be:
In Formula 1 Å, at least one of R12 and R13 includes deuterium. For example, at least one of R12 and R13 may be a group in which at least one hydrogen is substituted with deuterium.
In one or more embodiments, at least one of R12 and R13 may be a C1-C20 alkyl group substituted with at least one deuterium, a C3-C10 cycloalkyl group substituted with at least one deuterium, a C6-C60 aryl group substituted with at least one deuterium, or a C1-C60 heteroaryl group substituted with at least one deuterium.
In one or more embodiments, ring CY3 may be i) a first ring, ii) a condensed ring group in which two or more first rings are condensed with each other, or iii) a condensed ring group in which one or more second rings are condensed with each other,
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.
For example, ring CY4 may be a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, or a triazine group.
In one or more embodiments, a moiety represented by
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.
In one or more embodiments, a moiety represented by
Y1 in Formula 1B is O, S, Se, C(R5)(R6), N(R7), Si(R8)(R9), or Ge(R8)(R9).
R3 to R9, R41, and R42 in Formula 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-C1 cycloalkyl group, a substituted or unsubstituted C1-C1 heterocycloalkyl group, a substituted or unsubstituted C3-C10 cycloalkenyl group, a substituted or unsubstituted C2-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, R3 to R9, R41, and R42 in Formula 1B may each independently be:
In one or more embodiments, R3 to R9, R41, and R42 in Formula 1B may each independently be:
Formulae 9-1 to 9-61, 9-201 to 9-237, 10-1 to 10-129, and 10-201 to 10-350 may each be as described herein.
In one or more embodiments, the organometallic compound represented by Formula 1 may be represented by at least one of Formulae 5-1 to 5-6:
In one or more embodiments, the organometallic compound represented by Formula 1 may be represented by at least one of Compounds 1 to 132:
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 1 Å and a ligand represented by Formula 1B. In the ligand represented by Formula 1 Å, a substituent including deuterium (e.g., an alkyl group substituted with deuterium, or the like) is introduced at positions represented by R11 and/or R12. Thus, a light-emitting device including at least one of the organometallic compounds may have improved characteristics in terms of external quantum efficiency, roll-off ratio, and lifespan.
Accordingly, an electronic device, for example, an organic light-emitting device, including at least one of the organometallic compounds represented by Formula 1 may have a low driving voltage, a high external quantum efficiency, a long lifespan, and a reduced occurrence of roll-off.
The highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) energy level, triplet (Ti) energy level, and singlet (Si) energy level of some compounds of the organometallic compound 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 have 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 maximum emission wavelength (emission peak wavelength, λmax) of an emission peak of an emission spectrum or electroluminescence (EL) spectrum of the organometallic compound may be about 490 nanometers (nm) to about 550 nm, or about 500 nm to about 550 nm, or about 490 nm to about 540 nm, or about 500 nm to about 540 nm, or about 500 nm to about 535 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 below.
The organometallic compound represented by Formula 1 is 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, according to another aspect, provided is an organic light-emitting device including 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 represented by Formula 1.
The organic light-emitting device may include an organic layer including at least one of the organometallic compounds represented by Formula 1. Thus, the organic light-emitting device may have excellent characteristics in terms of driving voltage, current efficiency, external quantum efficiency, roll-off ratio, and lifespan, and a relatively narrow full width at half maximum (FWHM) of an emission peak in an EL spectrum.
The organometallic compound of 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). In one or more embodiments, 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 a total weight of the emission layer.
In one or more embodiments, the emission layer may emit a green light. For example, the emission layer may emit a green light having a maximum emission wavelength of about 490 nm to about 550 nm, or about 500 nm to about 550 nm, or about 490 nm to about 540 nm, or about 500 nm to about 540 nm, or about 500 nm to about 535 nm.
The expression “(an organic layer) includes at least one of the organometallic compounds” 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 organometallic compound, 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 organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be present in an identical layer (e.g., Compound 1 and Compound 2 may all 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 located between the first electrode and the emission layer and an electron transport region located 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 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 a metal.
The
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, 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, may be used.
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 (AI), 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 a plurality of 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 constituting layers for each structure are sequentially stacked in the stated order 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.
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 in a range of about 10−8 torr to about 10−3 torr, and a deposition rate in a range 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.
The 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.
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), p-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, a compound represented by Formula 202, or a combination thereof, but embodiments are not limited thereto:
xa and xb in Formula 201 may each independently be an integer from 0 to 5, or xa and xb 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 201 Å, but embodiments are not limited thereto:
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 in a range of 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 in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.
The 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 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 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, Compound F12, or the like, 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 increase efficiency.
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. 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 the materials for forming a hole transport region and host materials described herein, but embodiments are not limited thereto. For example, when the hole transport region includes an electron blocking layer, the material for forming the electron blocking layer may be mCP, which will be described below.
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-1 H-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, Compound H51, or a combination thereof, 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:
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 may each independently be 0, 1, or 2.
Ar113 to Ar116 in Formula 301 may each independently be:
In one or more embodiments, the host may include a compound represented by Formula 302, but embodiments are not limited thereto:
Ar126 and Ar127 in Formula 302 may each independently be a C1-C10 alkyl group (e.g., a methyl group, an ethyl group, a propyl group, or the like).
k and I in Formula 302 may each independently be an integer from 0 to 4. For example, k and I 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. When the thickness of the emission layer is within this range, excellent light-emission 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), bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), or a combination thereof, 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. When the thickness of the hole blocking layer is within this range, excellent hole blocking characteristics may be obtained without a substantial increase in driving voltage.
The electron transport layer may 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), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), or a combination thereof, but embodiments are not limited thereto:
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. When the thickness of the electron transport layer is within this range, 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 quinolate, 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. When the thickness of the electron injection layer is within this range, 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 (Li), magnesium (Mg), aluminum (AI), 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 has been described with reference to the FIGURE, but embodiments are not limited thereto.
According to another aspect, also provided is 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 also 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, but embodiments are not limited thereto.
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 may 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 may include a methoxy group, an ethoxy group, an isopropyloxy group, or the like.
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 may 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 may 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 may 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-C1 heterocycloalkyl group” as used herein refers to a monovalent cyclic group having at least one heteroatom selected from B, N, O, P, Si, Se, Ge, and S as a ring-forming atom and 1 to 10 carbon atoms as ring-forming atom(s), and non-limiting examples thereof may include a tetrahydrofuranyl group, a tetrahydrothiophenyl group, or the like. The term “C1-C1 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 having 3 to 10 carbon atoms, at least one carbon-carbon double bond in the ring thereof, and no aromaticity, and non-limiting examples thereof may 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-C1 heterocycloalkenyl group” as used herein refers to a monovalent cyclic group having at least one heteroatom selected from B, N, O, P, Si, Ge, Se, and S 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-C1 heterocycloalkenyl group may include a 2,3-dihydrofuranyl group, a 2,3-dihydrothiophenyl group, or the like. The term “C1-C1 heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C1-C1 heterocycloalkenyl group.
The term “C—C60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. The term “C—C60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C—C60 aryl group may 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 an aromatic ring system that has at least one heteroatom selected from B, N, O, P, Si, Se, Ge, and S as a ring-forming atom and 1 to 60 carbon atoms as ring-forming atom(s). The term “C1-C60 heteroarylene group” as used herein refers to a divalent group having an aromatic ring system that has at least one heteroatom selected from B, N, O, P, Se, Ge, and S 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 may 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). 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). 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 about 8 to about 60 carbon atoms) having 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 may 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 about 1 to about 60 carbon atoms) having two or more rings condensed with each other, a heteroatom selected from B, N, O, P, Si, Ge, Se, and S, other than carbon atoms, as a ring-forming atom(s), and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group may include a carbazolyl group or 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 cyclic 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 cyclic group having, as a ring-forming atom, at least one heteroatom selected from B, N, O, Si, P, Ge, Se, and S other than 1 to 30 carbon atoms as ring-forming atom(s). 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-C1 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, a compound and an organic light-emitting device according to one or more embodiments will be described in further detail with reference to Synthesis Examples and Examples, but embodiments are 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.
4,5-bis(methyl-d3)-2-phenylpyridine (3.62 grams (g), 19.14 millimoles (mmol)) and iridium chloride trihydrate (3.00 g, 8.51 mmol) were mixed with 90 milliliters (mL) of 2-ethoxyethanol and 30 mL of deionized (DI) water. The resultant reaction mixture was stirred and heated under reflux for 24 hours, and then, the temperature was allowed to lower to room temperature. A solid produced therefrom was separated by filtration, washed sufficiently with DI water, methanol, and hexane, in this stated order, and then dried in a vacuum oven to obtain 4.52 g (yield of 88%) of Compound 1A(1).
Compound 1A(1) (1.5 g, 1.24 mmol) and 60 mL of methylene chloride were mixed, and then, a separate solution was added thereto that included silver trifluoromethanesulfonate (AgOTf) (0.67 g, 2.61 mmol) combined with 20 mL of methanol. Afterwards, the resultant reaction mixture was stirred for 18 hours at room temperature while light was blocked with aluminum foil. The contents were then filtered through a Celite plug to remove a solid produced therein. The filtrate was separated and the solvent was removed under a reduced pressure to obtain a solid (Compound 1 Å) that was then used in the next reaction step without an additional purification process.
Under a nitrogen environment, 2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxoborolane (0.75 g, 2.54 mmol) and 2-bromo-1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-1H-benzo[d]imidazole (1.00 g, 2.31 mmol) were dissolved in 60 mL of 1,4-dioxane. Then, a separate solution prepared by dissolving potassium carbonate (K2CO3) (0.73 g, 5.28 mmol) in 20 mL of DI water was added to the reaction mixture. A palladium catalyst was then added to the reaction mixture (tetrakis(triphenylphosphine)palladium(0), Pd(PPh3)4) (0.13 g, 0.12 mmol). Afterwards, the resultant reaction mixture was stirred and heated under reflux at 100° C. The reaction was then allowed to cool to room temperature. The product was isolated by extraction and a solid thus obtained was purified by column chromatography (eluents: ethyl acetate (EA) and n-hexane) to obtain 1.10 g (yield of 91%) of Compound 1B. 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 C37H32N2O: m/z: 520.68; found: 521.62.
Compound 1A(1.5 g, 1.92 mmol) and Compound 1B (2-(dibenzo[b,d]furan-4-yl)-1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-1 H-benzo[d]imidazole) (1.10 g, 2.12 mmol) were mixed with 10 mL of 2-ethoxyethanol and 10 mL of N,N-dimethylformamide. The resultant reaction mixture was stirred and heated under reflux for 24 hours. The temperature was then allowed to lower to room temperature. The solvent was removed from the product under a reduced pressure, and a solid thus obtained was purified by column chromatography (eluents: methylene chloride (MC) and n-hexane) to obtain 0.75 g (yield of 36%) of Compound 1. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calculated for C63H43D12IrN4O: m/z: 1088.45; found: 1089.44.
0.82 g (yield of 37%) of Compound 10 was obtained in a similar manner as used to synthesize Compound 1, except that 4,4,5,5-tetramethyl-2-(7-phenyldibenzo[b,d]furan-4-yl)-1,3,2-dioxoborolane (0.94 g, 2.54 mmol) was used instead of 2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxoborolane. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calcd for C69H47D12IrN4O: m/z: 1164.55; found: 1165.52.
0.74 g (yield of 33%) of Compound 16 was obtained in a similar manner as used to synthesize Compound 1, except that 4,4,5,5-tetramethyl-2-(1-(methyl-d3)-7-phenyldibenzo[b,d]furan-4-yl)-1,3,2-dioxoborolane (0.98 g, 2.54 mmol) was used instead of 2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxoborolane. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calculated for C70H46D15IrN4O: m/z: 1181.59; found: 1182.64.
0.72 g (yield of 34%) of Compound 91 was obtained in a similar manner as used to synthesize Compound 1, except that 5-(methyl-d3)-2-phenylpyridine (3.30 g, 19.14 mmol) was used instead of 4,5-bis(methyl-d3)-2-phenylpyridine. The obtained compound was identified by HRMS (MALDI) and HPLC analysis.
HRMS (MALDI) calculated for C61H45D6IrN4O: m/z: 1054.36; found: 1055.27.
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 exposure to ultraviolet rays and ozone for 30 minutes each. The resultant 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 1,650 Å.
Then, Compound GH3 (host) and Compound 1 (dopant) were co-deposited on the hole transport layer at a weight ratio of 92:8 to form an emission layer having a thickness of 400 Å.
Afterwards, Compound ETL and LiQ-N-Dopant were co-deposited 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 compounds shown in Table 2 were each used instead of Compound 1 in forming an emission layer.
The driving voltage (Volts, V), roll-off ratio (%), maximum emission wavelength (nm), maximum external quantum efficiency (Max EQE, %), and lifespan (LT97, relative %) of each of the organic light-emitting devices manufactured according to Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated, and the results thereof are shown in Table 2. As evaluation apparatuses, a current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1000 A) were used. The lifespan (LT97) (at 18,000 candela per square meter (cd/m2)) was evaluated as the time taken for luminance to be reduced to 97% of the initial luminance of 100%. The roll-off ratio was calculated according to Equation 1.
Roll-off ratio={1−(efficiency (at 3,500 cd/m2)/maximum emission efficiency)}×100% Equation 1
Referring to Table 2, the organic light-emitting devices of Examples 1 to 4 were found to have characteristics of lower driving voltage, increased external quantum efficiency, reduced roll-off ratio, and longer lifespan.
Referring to Table 2, the organic light-emitting devices of Examples 1 to 4 were found to have lower driving voltage, lower roll-off ratio, higher external quantum efficiency, and longer lifespan than the organic light-emitting devices of Comparative Examples 1 and 2.
Since the organometallic compound has excellent electrical characteristics, an electronic device, for example, an organic light-emitting device, including at least one of the organometallic compounds described herein may have characteristics of a low driving voltage, a high external quantum efficiency, a low roll-off ratio, and a long lifespan. Accordingly, by using the organometallic compound, a high-quality organic light-emitting device may be implemented.
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 |
|---|---|---|---|
| 10-2022-0097566 | Aug 2022 | KR | national |
