Patent Application
20230217805
This application is based on and claims priority to Korean Patent Application No. 10-2021-0143081, filed on Oct. 25, 2021, and all benefits accruing therefrom under 35 U.S.C. §119, in the Korean Intellectual Property Office, the entire content of which is incorporated by reference herein.
The present disclosure relates to organometallic compounds, organic light-emitting devices including the same, and electronic apparatuses including the organic light-emitting devices.
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, and 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 recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light.
Provided are organometallic compounds, organic light-emitting devices including the same, and electronic apparatuses including the organic light-emitting devices.
Additional aspects will be set forth in part in the detailed description, which follows and, in part, will be apparent from the detailed description, or may be learned by practice of the presented exemplary embodiments of the disclosure.
According to an aspect, provided is an organometallic compound represented by Formula 1:
Wherein, in Formulae 1A and 1B,
According to another aspect, provided is 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 organometallic compound.
The at least one organometallic compound may be included in the emission layer of the organic layer, and in this regard, may act as a dopant.
According to still another aspect, provided is an electronic apparatus including the organic light-emitting device.
The above and other aspects, features, and advantages of certain exemplary embodiments of the disclosure will be more apparent from the following detailed description taken in conjunction with the
Reference will now be made in detail to one or more embodiments, examples of which are illustrated in the accompanying drawing, wherein like reference numerals refer to like elements throughout the specification. In this regard, the present exemplary embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described in further detail below, by referring to the
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.” As used herein, the term “and/or” includes any and all combinations of one or more of the same associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. It will be 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 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 of the present disclosure provides an organometallic compound represented by Formula 1:
wherein, n Formula 1, M1 is a transition metal.
For example, M1 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 (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), thulium (Tm), or rhodium (Rh).
In one or more embodiments, M1 may be Ir, Pt, Os, or Rh.
In one or more embodiments, M1 may be Ir.
In Formula 1, n1 is 1 or 2, and n2 is 1, 2, or 3.
In one or more embodiments, a sum of n1 and n2 may be 2 or 3.
In one or more embodiments, M1 may be Ir, and the sum of n1 and n2 may be 3.
In one or more embodiments, M1 may be Pt, and the sum of n1 and n2 may be 2.
In Formula 1, Ln1 is a ligand represented by Formula 1A:
In Formula 1A, Y1 may be O, S, Se, or C(R1)(R2).
In one or more embodiments, Y1 may be O or S.
In one or more embodiments, Ln1 may include —Si(Q1)(Q2)(Q3) or —Ge(Q1)(Q2)(Q3).
In Formula 1, Ln2 is a ligand represented by Formula 1B:
In Formula 1B, ring CY3 is: (i) a 5-membered N-containing heterocyclic group; or (ii) a 5-membered N-containing heterocyclic group condensed with a C5-C30 carbocyclic group or a C1-C30 heterocyclic group.
In one or more embodiments, ring CY3 may be a 1 H-pyrrole group, a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, a benzimidazole group, an imidazopyridine group, an imidazopyrimidine group, or an imidazopyrazine group.
In Formula 1B, ring CY4 is: (i) a 6-membered carbocyclic group; (ii) a 6-membered heterocyclic group; (iii) a 6-membered carbocyclic group condensed with a C5-C30 carbocyclic group or a C1-C30 heterocyclic group; or (iv) a 6-membered heterocyclic group condensed with a C5-C30 carbocyclic group or a C1-C30 heterocyclic group.
In one or more embodiments, ring CY4 may be a phenyl group, a naphthalene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a phenanthroline group, a quinoxaline group, or a quinazoline group.
In Formula 1B, Y2 is O or S.
In one or more embodiments, Y2 may be O.
In one or more embodiments, Ln2 may be represented by Formula 1B-1 or 1B-2:
In Formulae 1B-1 and 1B-2,
In one or more embodiments, a moiety represented by
in Formula 1B may be represented by one of Formulae 3-1 to 3-12:
In Formulae 3-1 to 3-12,
In Formula 1, R1 to R6, R10, R20, R30, and R40 to R42 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 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 Formula 1B, b30 is 1, 2, 3, 4, 5, or 6.
In one or more embodiments, b30 may be 1, 2, 3, 4, or 5.
In one or more embodiments, b30 may be 1, 2, or 3.
In Formula 1B, b40 is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
In one or more embodiments, b40 may be 1, 2, 3, 4, 5, 6, 7, or 8.
In one or more embodiments, b40 may be 1, 2, 3, 4, 5, or 6.
In one or more embodiments, b40 may be 1, 2, 3, or 4.
In one or more embodiments, b40 may be 1 or 2.
In one or more embodiments, R10, R20, R30, and R40 to R42 may each independently be:
In one or more embodiments, R10, R20, R30, and R40 to R42 may each independently be:
In Formulae 9-1 to 9-61, 9-201 to 9-237, 10-1 to 10-129, and 10-201 to 10-350, * indicates a binding site to a neighboring atom, “Ph” is a phenyl group, “TMS” is a trimethylsilyl group, and “TMG” is a trimethylgermyl group.
In Formulae 1A and 1B, two or more of a plurality of R30; two or more of a plurality of R40; or neighboring two or more of R1, R2, R11 to R14, R21 to R26, R30, and R40 are optionally linked together to form a substituted or unsubstituted C5-C30 carbocyclic group or a substituted or unsubstituted C1-C30 heterocyclic group.
In one or more embodiments, two or more of a plurality of R30; two or more of a plurality of R40; or neighboring two or more of R1, R2, R11 to R14, R21 to R26, R30, and R40 may optionally be linked together via a single bond, a double bond, or a first linking group to form a C5-C30 carbocyclic group that is unsubstituted or substituted with at least one R10a or a C1-C30 heterocyclic group that is unsubstituted or substituted with at least one R10a (for example, a fluorene group, a xanthene group, an acridine group, or the like, each unsubstituted or substituted with at least one R10a). R10a may be as described in connection with R11.
The first linking group may be selected from *—N(R8)—*′, *—B(R8)—*′, *—P(R8)—*′, *—C(R8)(R9)—*′, *—Si(R8)(R9)—*′, *—Ge(R8)(R9)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)2—*′, *—C(R8)═*′, *═C(R8)—*′, *—C(R8)═C(R9)—*′, *—C(═S)—*′, and *—C≡C—*′, R8 and R9 may each independently be as described in connection with R11, and * and *′ each indicate a binding site to a neighboring atom.
In one or more embodiments, Q1 to Q9, Q11 to Q19, Q21 to Q29, and Q31 to Q39 may each independently be:
In one or more embodiments, the organometallic compound may be represented by Formula 30-1 to 30-2:
In Formulae 30-1 and 30-2,
In one or more embodiments, examples of the “C5-C30 carbocyclic group that is unsubstituted or substituted with at least one R10a or a C1-C30 heterocyclic group that is unsubstituted or substituted with at least one R10a” include a phenyl (benzene) group, a naphthalene group, a cyclopentane group, a cyclopentadiene group, a cyclohexane group, a cycloheptane group, a bicyclo[2.2.1]heptane group, a furan group, a thiophene group, a pyrrole group, a silole group, an indene group, a benzofuran group, a benzothiophene group, an indole group, or a benzosilole group, each unsubstituted or substituted with at least one R10a. R10a may be as described in connection with R11. The C5-C30 carbocyclic group and the C1-C30 heterocyclic group may respectively be as described herein.
In one or more embodiments, at least one of R10(s) in the number of b10, R20(S) in the number of b20, R30(S) in the number of b30, R40(S) in the number of b40, R41, and R42 may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl, an isopentyl, a 2-methylbutyl group, a sec-pentyl, a tert-pentyl, a neo-pentyl, a 3-pentyl, a 3-methyl-2-butyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a phenyl group, a biphenyl group, a C1-C20 alkylphenyl group, a naphthyl group, —Si(Q1)(Q2)(Q3), or —Ge(Q1)(Q2)(Q3), each unsubstituted or substituted with at least one deuterium.
In one or more embodiments, at least one of R11 to R14 may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a 2-methylbutyl group, a sec-pentyl group, a tert-pentyl group, a neo-pentyl group, a 3-pentyl group, a 3-methyl-2-butyl group, a cyclopentyl group, or a cyclohexyl group.
In one or more embodiments, at least one of R30(S) in the number of b30 may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a 2-methylbutyl group, a sec-pentyl group, a tert-pentyl group, a neo-pentyl group, a 3-pentyl group, a 3-methyl-2-butyl group, a phenyl group, or a naphthyl group.
In one or more embodiments, in Formulae 1B-1, 1B-2, 3-1 to 3-12, 30-1, or 30-2, at least one of R30(s) in the number of b30 may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a 2-methylbutyl group, a sec-pentyl group, a tert-pentyl group, an neo-pentyl group, a 3-pentyl group, a 3-methyl-2-butyl group, a phenyl group, or a naphthyl group.
In one or more embodiments, in Formula 1A, at least one of R11 to R14 may be Si(Q1)(Q2)(Q3) or —Ge(Q1)(Q2)(Q3).
In one or more embodiments, in Formula 1A, at least one of R21 to R26 may be Si(Q1)(Q2)(Q3) or —Ge(Q1)(Q2)(Q3).
In one or more embodiments, in Formula 1A, at least one of R11 and R21 to R24 may be Si(Q1)(Q2)(Q3) or-Ge(Q1)(Q2)(Q3).
In one or more embodiments, the organometallic compound may include one to four silyl groups (-Si(Q1)(Q2)(Q3)) and/or one or four germyl groups (-Ge(Q1)(Q2)(Q3)).
In one or more embodiments, the organometallic compound may include one or two silyl groups (-Si(Q1)(Q2)(Q3)) and/or one or two germyl groups (-Ge(Q1)(Q2)(Q3)).
In one or more embodiments, the organometallic compound may include one silyl group (-Si(Q1)(Q2)(Q3)) or one germyl group (-Ge(Q1)(Q2)(Q3)).
In one or more embodiments, the organometallic compound may be one of Compounds 1 to 56:
In one or more embodiments, the organometallic compound may be electrically neutral.
The organometallic compound represented by Formula may satisfy the structure of Formula 1, include the ligands represented by Formulae 1A and 1B, and may be substituted with at least one silyl group or at least one germyl group. Due to this structure, the organometallic compound represented by Formula 1 has 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, the organometallic compound represented by Formula 1 has excellent electrical mobility, and thus, electronic devices including the organometallic compound, for example, organic light-emitting devices including the organometallic compound may show low driving voltage, high efficiency, a long lifespan, and reduced roll-off phenomenon.
In addition, the photochemical stability of the organometallic compound represented by Formula 1 is improved, and thus, electronic devices including the organometallic compound, for example, organic light-emitting devices including the organometallic compound may show high emission efficiency, long lifespan, and high color purity.
The highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) energy level, energy gap, triple (T1) energy level, single (S1) energy level, of organometallic compounds represented by Formula 1 were evaluated by density functional theory (DFT) using the Gaussian 09 program with the molecular structure optimization obtained at the B3LYP basis level , and results thereof are shown in Table 1 with energy levels reported as electron Volts (eV).
Referring to Table 1, it was confirmed that the organometallic compound represented by Formula 1 has suitable electrical characteristics for use as a dopant in an electric device, for example, an organic light-emitting device.
In one or more embodiments, the full width at half maximum (FWHM) of the emission peak of the emission spectrum or the electroluminescence spectrum of the organometallic compound may be 70 nanometers (nm) or less. For example, the FWHM of the emission peak of the emission spectrum or the electroluminescence spectrum of the organometallic compound may be from about 30 nm to about 65 nm, from about 40 nm to about 63 nm, or from about 45 nm to about 62 nm.
In one or more embodiments, the maximum emission wavelength (emission peak wavelength, λmax) of the emission peak of the emission spectrum or electroluminescence spectrum of the organometallic compound may be from about 490 nm to about 550 nm.
Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art by referring to Synthesis Examples described below.
Accordingly, the organometallic compound represented by Formula 1 may be suitable for use as a dopant in an organic layer, for example, an emission layer, of an organic light-emitting device. Thus, another aspect of the present disclosure provides an organic light-emitting device including: a first electrode; a second electrode; and an organic layer that is located between the first electrode and the second electrode and includes an emission layer, wherein the organic layer includes at least one organometallic compound represented by Formula 1.
As described above, due to the inclusion of the organic layer including the organometallic compound represented by Formula 1, the organic light-emitting device may have excellent characteristics in terms of driving voltage, current efficiency, power efficiency, external quantum efficiency, lifespan, and/or color purity. Also, such an organic light-emitting device may have a reduced roll-off phenomenon and a relatively narrow electroluminescent (EL) spectrum emission peak FWHM.
The organometallic compound represented by Formula 1 may be used between a pair of electrodes of the organic light-emitting device. For example, the organometallic compound 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 organometallic compound represented by Formula 1 in the emission layer is smaller than an amount of the host included in the emission layer).
In one or more embodiments, the emission layer may emit green light. For example, the emission layer may emit red light having a maximum emission wavelength in a range of about 490 nm to about 550 nm.
The expression “(an organic layer) includes at least one organometallic compound 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”.
In one or more embodiments, the organic layer may include, as the organometallic compound, only Compound 1. In this embodiment, Compound 1 may be included 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 embodiment, Compound 1 and Compound 2 may exist in an identical layer (for example, Compound 1 and Compound 2 may all exist 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; or 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.
In one or more embodiments, 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 located 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
A substrate may be additionally arranged under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate that is used in organic light-emitting devices available in the art may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/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. In one or more embodiments, 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 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 the structure of the first electrode 11 is not limited thereto.
The organic layer 15 is located on the first electrode 11.
The organic layer 15 may include: the hole transport region; the emission layer; and the electron transport region.
The hole transport region may be located 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 either a hole injection layer or a hole transport layer. 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 this 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 a 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 in a range 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. However, the deposition conditions 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 properties of the hole injection layer. For example, the coating conditions may include a coating speed in a range of about 2,000 revolutions per minute (rpm) to about 5,000 rpm and a heat treatment temperature for removing a solvent after coating in a range of about 80° C. to about 200° C. However, the coating conditions are not limited thereto.
Conditions for forming the hole transport layer and the electron blocking layer may be as the conditions for forming the hole injection layer.
The hole transport region may include 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, or a compound represented by Formula 202:
wherein, in Formula 201, Ar101 and Ar102 may each independently be:
In Formula 201, xa and xb 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 xa and xb are not limited thereto.
In Formulae 201 and 202, R101 to R108, R111 to R119, and R121 to R124 may each independently be:
In Formula 201, R109 may be:
In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments of the present disclosure are not limited thereto:
wherein, in Formula 201A, R101, R111, R112, and R109 may each independently be as described herein.
For example, the compound represented by Formula 201 and the compound represented by Formula 202 may include one or more of Compounds HT1 to HT20, but embodiments of the present disclosure are not limited thereto:
A thickness of the hole transport region may be in a range of 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 these materials, a charge-generation material for the improvement of 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, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Nonlimiting examples of the p-dopant are a quinone derivative, such as tetracyanoquinodimethane (TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdenum oxide; or a cyano group-containing compound, such as Compound HT-D1 or F12, but are not limited thereto:
The hole transport region may include a buffer layer.
Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.
Then, 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 although the deposition or coating conditions may vary according to a material that is used to form the hole transport layer.
Meanwhile, 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 above and host materials to be explained later. However, the material for forming the electron blocking layer is 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 the organometallic compound represented by Formula 1.
In one or more embodiments, the host may include at least one of 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (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′-dimethylbiphenyl (CDBP), N,N,′N″-1,3,5-tricarbazoloylbenzene (TCP), 1,3-bis(carbazol-9-yl)benzene (mCP), Compound H50, or Compound H51:
In one or more embodiments, the host may further include a compound represented by Formula 301:
wherein, in Formula 301, Ar111 and Ar112 may each independently be:
In Formula 301, Ar113 to Ar116 may each independently be:
In Formula 301, g, h, i, and j may each independently be an integer from 0 to 4, and for example, may each independently be 0, 1, or 2.
In Formula 301, Ar113 to Ar116 may each independently be:
In one or more embodiments, the host may include a compound represented by Formula 302:
wherein, in Formula 302, Ar122 to Ar125 may each independently be as described in connection with Ar113 in Formula 301.
In Formula 302, Ar126 and Ar127 may each independently be a C1-C10 alkyl group (for example, a methyl group, an ethyl group, or a propyl group).
In Formula 302, k and I 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 10, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, based on 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 in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.
A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within these ranges, excellent luminescence characteristics may be obtained without a substantial increase in driving voltage.
Next, the electron transport region is located 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 the structure of the electron transport region is 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 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(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (BAlq), but embodiments of the present disclosure are not limited thereto:
A thickness of the hole blocking layer may be in a range of 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 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 BCP, Bphen, Alq3, 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):
In one or more embodiments, the electron transport layer may include at least one of Compounds ET1 to ET25, but embodiments of the present disclosure are not limited thereto:
A thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron 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 include a metal-containing material in addition to the material as described above.
The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate (LiQ)) or ET-D2:
The electron transport region may include an electron injection layer that promotes the flow of electrons from the second electrode 19 thereinto.
The electron injection layer may include LiF, NaCl, CsF, Li2O, BaO, or a combination thereof.
A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer 162 is within these ranges, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.
The second electrode 19 is located on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be metal, an alloy, an electrically conductive compound, or a combination thereof, which has a relatively low work function. For example, the material for forming the second electrode 19 may be lithium (Li), magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag). 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
Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.
The organometallic compound represented by Formula 1 provides high luminescence efficiency, and accordingly, the diagnostic composition including the at least one organometallic compound may have high diagnostic efficiency.
The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.
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 are 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, and 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” used herein refers to a monovalent group represented by -OA101 (wherein A101 is the C1-C60 alkyl group), and examples thereof are a methoxy group, an ethoxy group, an isopropyloxy group, and 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 examples thereof are an ethenyl group, a propenyl group, a butenyl group, and 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 examples thereof are an ethynyl group, a propynyl group, and the like. The term “C2-C60 alkynylene group” as used herein refers to a divalent group having the same structure as the C2-C60 alkynyl group.
The term “C3-C10 cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms, and examples thereof are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and 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 saturated monocyclic group having at least one heteroatom selected from N, O, P, Si, Ge, Se, and S as a ring-forming atom and 1 to 10 carbon atoms, and examples thereof are a tetrahydrofuranyl group, a tetrahydrothiophenyl group, and 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 monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and examples thereof are a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, and 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 “C2-C10 heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one hetero atom selected from N, O, P, Si, Ge, Se, and S as a ring-forming atom, 2 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Examples of the C1-C10 heterocycloalkenyl group are a 2,3-dihydrofuranyl group, a 2,3-dihydrothiophenyl group, and the like. The term “C2-C10 heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C2-C10 heterocycloalkenyl group.
The term “C6-C60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C6-C60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Examples of the C6-C60 aryl group are a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, a chrysenyl group, and 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 system that has at least one heteroatom selected from N, O, P, Si, Ge, Se, and S as a ring-forming atom, and 1 to 60 carbon atoms. The term “C1-C60 heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, Ge, Se, and S as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C1-C60 heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, and the like. When the C6-C60 heteroaryl group and the C6-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 indicates -OA102 (wherein A102 is the C6-C60 aryl group), and the term “C6-C60 arylthio group” as used herein indicates -SA103 (wherein A103 is the C6-C60 aryl group).
The term “C1-C60 heteroaryloxy group” used herein indicates -OA104 (wherein A104 is a C1-C60 heteroaryl group), and the term “C1-C60 heteroarylthio group” as used herein indicates -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 (for example, having 8 to 60 carbon atoms) having two or more rings condensed to each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic condensed polycyclic group are a fluorenyl group and 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 described above.
The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) having two or more rings condensed with each other, a heteroatom selected from N, O, P, Si, Ge, Se, 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 are 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 described above.
The term “C5-C30 carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C5-C30 carbocyclic group may be a monocyclic group or a polycyclic group.
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 N, O, Si, P, Ge, Se, and S other than 1 to 30 carbon atoms. The C1-C30 heterocyclic group may be a monocyclic group or a polycyclic group.
In the present specification, TMS represents * —Si(CH3)3, and TMG represents * —Ge(CH3)3.
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 hetero arylthio 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 embodiments are described in detail with reference to Synthesis Examples and Examples. However, the compound and the organic light-emitting device are not limited thereto. The wording “‘B’ was used instead of ‘A’” used in describing Synthesis Examples means that an amount of ‘A’ used was identical to an amount of ‘B’ used, in terms of a molar equivalent.
Synthesis Example 1: Synthesis of Compound 1
Under a nitrogen environment, 2-chloro-4-isopropylpyridine (1.5 grams (g), 9.6 millimoles (mmol)) and (7-(trimethylsilyl)dibenzo[b,d]furan-4-yl)boronic acid (3.3 g, 11.6 mmol) were dissolved in 180 milliliters (mL) of 1,4-dioxane. Next, a solution containing potassium carbonate (K2CO3) (3.1 g, 22.4 mmol) dissolved in 60 mL of deionized (DI) water was added thereto, and then a palladium catalyst (tetrakis(triphenylphosphine)palladium(0), Pd(PPh3)4) (0.25 g, 0.22 mmol) was also added thereto. Afterwards, the resultant reaction mixture was stirred and heated under reflux at a temperature of 110° C. After allowing it to cool to room temperature, an extraction process was performed thereon, a solid thus obtained was subjected to column chromatography (eluent: ethyl acetate (EA) and hexanes) to obtain (4-isopropyl-2-(7-(trimethylsilyl)dibenzo[b,d]furan-4-yl)pyridine (Compound 1A(1)) 2.9 g (yield of 84%). The obtained compound was identified by high resolution mass spectrometry (HRMS using matrix assisted laser desorption ionization (MALDI)) and HPLC analysis.
HRMS (MALDI) calcd for C23H25NOSi: m/z: 359.54 Found: 360.14.
Compound 1A(1) (8.6 g, 23.8 mmol) and iridium chloride (4.0 g, 13.4 mmol) were mixed with 120 mL of 2-ethoxyethanol and 40 mL of DI water, and stirred and heated under reflux for 24 hours. Then, the reaction temperature was allowed to lower to room temperature. The resulting solid was separated by filtration, washed sufficiently with DI water, methanol, and hexanes, in this stated order, and then dried in a vacuum oven to obtain 9.2 g (yield of 87%) of Compound 1A. Compound 1A obtained was used in the next reaction without an additional purification process.
Compound 1A (1.5 g, 0.79 mmol), 2-(1-methyl-1H-benzo[d]imidazol-2-yl)phenol (0.4 g, 1.78 mmol), and sodium carbonate (Na2CO3) (0.3 g, 2.83 mmol) were added and mixed with 20 mL of 2-ethoxyethanol. The mixed solution was then stirred and heated under reflux for 3 hours, and then the reaction temperature was lowered to room temperature. The resulting solid was filtered and washed with DI water, methanol, and n-hexane, in this stated order, and then dried in a vacuum oven. The obtained solid was subjected to column chromatography (eluent: methylene chloride (MC) and hexanes) to obtain 0.72 g (yield of 80%) of Compound 1. The obtained compound was identified by HRMS and HPLC analysis.
HRMS (MALDI) calcd for C60H59IrN4O3Si2 : m/z: 1132.54 Found: 1133.52.
Synthesis Example 2: Synthesis of Compound 2
Compound 2 was obtained in a similar manner as in synthesis of Compound 1, except that (7-(trimethylgermyl)dibenzo[b,d]furan-4-yl)boronic acid was used instead of (7-(trimethylsilyl)dibenzo[b,d]furan-4-yl)boronic acid . The obtained compound was identified by HRMS and HPLC analysis.
HRMS (MALDI) calcd for C60H59Ge2IrN4O3 : m/z: 1221.63 Found: 1222.59.
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 (UV) rays and ozone for 30 minutes. The resultant ITO-patterned glass substrate was loaded onto a vacuum deposition apparatus.
Compound HT3 and Compound F12 (p-dopant) were vacuum-co-deposited on the anode at a weight ratio of 98:2 to form a hole injection layer having a thickness of 100 angstroms (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.
Subsequently, Compound GH3 (host) and Compound 1 (dopant) were co-deposited at a weight ratio of 92:8 on the hole transport layer to form an emission layer having a thickness of 400 Å.
Then, Compound ET3 and LiQ (n-dopant) were co-deposited on the emission layer at the volume ratio of 50:50 to form an electron transport layer having a thickness of 350 Å, LiQ 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 respectively used instead of Compound 1 as a dopant in forming an emission layer.
The driving voltage (volts, V), maximum emission wavelength (λmax, nm) in emission spectra, maximum external quantum efficiency (Max EQE, %), and roll-off ratio (%) of each of the organic light-emitting devices of Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated, and results thereof are shown in Table 2. As evaluation apparatuses, a current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1000A) were used. The roll-off ratio was calculated according to Equation 20.
Roll-off ratio = {1- (efficiency / maximum luminescence efficiency)} X 100 %
Referring to Table 2, it was confirmed that the organic light-emitting devices of Examples 1 and 2 had low driving voltage and low roll-off ratio and high EQE. In detail, it was confirmed that the organic light-emitting devices of Examples 1 and 2 had lower driving voltage and lower roll-off ratio and higher EQE than those of the organic light-emitting devices of Comparative Examples 1 to 3.
As described above, according to the one or more embodiments, an organometallic compound may have excellent electrical characteristics and thermal stability. In particular, the organometallic compound has a high glass transition temperature so that crystallization thereof may be prevented, and electric mobility thereof may be improved. Accordingly, an electronic device, such as an organic light-emitting device, using the organometallic compound may have low driving voltage, high efficiency, a long lifespan, a reduced roll-off ratio, and a relatively narrow FWHM of an emission peak in an electroluminescence spectrum.
Thus, due to the use of the organometallic compound, a high-quality organic light-emitting device may be implemented. In addition, an electronic apparatus including the organic light-emitting device may be provided.
It should be understood that the 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 one or more other exemplary embodiments. While one or more embodiments have been described with reference to the
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0143081 | Oct 2021 | KR | national |
