Metal complex and organic electroluminescent device

Abstract

The invention provides a metal complex and an organic electroluminescent device, and belongs to the technical field of display. The organic light-emitting device is provided with an organic light-emitting layer, and the organic light-emitting layer is provided with a main body material, a sensitizing material and a doping material. Wherein the sensitizing material comprises a metal complex. The metal complex can improve the performance of the organic electroluminescent device.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically, to a metal complex and an organic electroluminescent device. Background Technology

[0002] Organic electroluminescent devices have attracted widespread attention due to their self-luminescence, high contrast, and low voltage characteristics. However, traditional fluorescent materials can only utilize singlet excitons (accounting for 25%) generated by electrical excitation, while triplet excitons (accounting for 75%) are dissipated in a non-radiative manner, resulting in a theoretical upper limit of only 25% for quantum efficiency.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a metal complex and an organic electroluminescent device to improve the performance of the organic electroluminescent device.

[0005] According to one aspect of this disclosure, a metal complex is provided, the chemical structural formula of which is shown in Formula 1:

[0006] Wherein, L1 is selected from alkyl groups having 1 to 3 carbon atoms, whether single-bonded, substituted, or unsubstituted; M is selected from iridium, platinum, ruthenium, osmium, copper, and gold; RA is selected from substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted fused aromatic heterocycles; RB is selected from substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic heterocycles, and RB has at least one SP. 2 Hybridized N; RC is selected from substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted fused aromatic heterocycles; X1 and X2 are each independently selected from C or N; n is selected from 1, 2, or 3; The chemical structural formula of Ar is shown in Formula 2 or Formula 3:

[0007] Among them, X3 is selected from O, S, Se, N, N(R1), C(R2R3), and C(O); RD is selected from substituted or unsubstituted aromatic rings, substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic rings, and substituted or unsubstituted fused aromatic heterocycles. RE is selected from substituted or unsubstituted aromatic rings, substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic rings, and substituted or unsubstituted fused aromatic heterocycles. R1, R2 and R3 are each independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl groups having 1 to 3 carbon atoms, or substituted or unsubstituted aryl groups having 6 to 12 carbon atoms; When L1, R1, R2, R3, RA, RB, RC, RD, or RE has substituents, the number of substituents is one or more, and each substituent is independently selected from deuterium, halogen, alkyl, alkoxy, aryloxy, alkylamino, arylamino, benzyloxy, benzylimino, or two adjacent substituents are connected to each other to form a 3- to 10-membered ring.

[0008] According to another aspect of this disclosure, an organic electroluminescent device is provided, the organic electroluminescent device having an organic light-emitting layer having a host material, a sensitizing material and a dopant material; wherein the sensitizing material includes the aforementioned metal complex.

[0009] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0010] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0011] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent device in one embodiment of the present disclosure.

[0012] Figure 2 This is a schematic diagram of the structure of an organic electroluminescent device in one embodiment of the present disclosure. Detailed Implementation

[0013] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0014] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0015] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0016] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0017] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0018] In this disclosure, the term "substituted or unsubstituted" means that the functional group described after the term may or may not have substituents (hereinafter, for ease of description, substituents are collectively referred to as Rx). For example, "substituted or unsubstituted aryl" refers to an aryl group having a substituent Rx or an unsubstituted aryl group. The substituent Rx can be, for example, deuterium, halogen groups, cyano, alkyl, alkoxy, alkylthio, haloalkyl, deuteralkyl, cycloalkyl, trialkylsilyl, triphenylsilyl, diarylphosphine, aryloxy, etc. In this disclosure, the "substituted" functional group can be substituted by one or more of the aforementioned substituents Rx.

[0019] In embodiments of this disclosure, the number of carbon atoms in substituted or unsubstituted groups refers to the total number of carbon atoms. For example, if Ar x If an aryl group is substituted with 12 carbon atoms, then the total number of carbon atoms in the aryl group and its substituents is 12.

[0020] The descriptive phrases used in this disclosure, such as "...each independently selected" and "...independently selected each time it appears," can mean that the specific options expressed by the same symbol in different groups do not affect each other, or that the specific options expressed by the same symbol in the same group do not affect each other. For example: in " In the description of "where each q is independently 0, 1, 2 or 3, and each R'' is independently selected from hydrogen, fluorine, chlorine", the meaning is: Formula Q-1 indicates that there are q substituents R'' on the benzene ring, and each R'' can be the same or different, and the options of each R'' do not affect each other; Formula Q-2 indicates that there are q substituents R'' on each benzene ring of biphenyl, and the number q of substituents 'R'' on the two benzene rings can be the same or different, and each R'' can be the same or different, and the options of each R'' do not affect each other.

[0021] In this disclosure, aryl refers to any optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group can be a monocyclic aryl (e.g., phenyl) or a polycyclic aryl; in other words, the aryl group can be a monocyclic aryl, a fused-ring aryl, two or more monocyclic aryl groups conjugated by carbon-carbon bonds, a monocyclic aryl and a fused-ring aryl group conjugated by carbon-carbon bonds, or two or more fused-ring aryl groups conjugated by carbon-carbon bonds. That is, two or more aromatic groups conjugated by carbon-carbon bonds can also be considered as aryl groups in this disclosure. Fused-ring aryl groups may include, for example, bicyclic fused aryl (e.g., naphthyl), tricyclic fused aryl (e.g., phenanthrene, fluorenyl, anthracene), etc. The aryl group does not contain heteroatoms such as B, N, O, S, Se, Si, or P. For example, in this disclosure, biphenyl, terphenyl, etc., are aryl groups. Examples of aryl groups may include, but are not limited to, phenyl, naphthyl, fluorenyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, tetraphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, hydroxyl, indene, etc.

[0022] In embodiments of this disclosure, the substituted aryl group may be one or more hydrogen atoms of the aryl group that are replaced by groups such as deuterium atoms, halogen groups, -CN, aryl, heteroaryl, trialkylsilyl, alkyl, cycloalkyl, alkoxy, alkylthioyl, etc. Specific examples of heteroaryl-substituted aryl groups include, but are not limited to, dibenzofuranyl-substituted phenyl, dibenzothiopheneyl-substituted phenyl, pyridyl-substituted phenyl, carbazoleyl-substituted phenyl, etc. It should be understood that the number of carbon atoms in the substituted aryl group refers to the total number of carbon atoms of the aryl group and the substituents on the aryl group. For example, a substituted aryl group with 18 carbon atoms means that the total number of carbon atoms of the aryl group and the substituents is 18.

[0023] In embodiments of this disclosure, a heteroaryl group refers to a monovalent aromatic ring or its derivative containing at least one heteroatom, where the heteroatom can be at least one of B, O, N, P, Si, Se, and S. The heteroaryl group can be a monocyclic or polycyclic heteroaryl group; in other words, it can be a single aromatic ring system or a system of multiple aromatic rings conjugated by carbon-carbon bonds, and any aromatic ring system can be a single aromatic monocyclic ring or a fused aromatic ring. For example, heteroaryl groups may include thiophene, furanyl, pyrrole, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinel, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxolinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, isoquinolinyl, indolyl, carbazole, benzoxazolyl, and benzimidazole. The group includes, but is not limited to, benzothiazolyl, benzocarbazolyl, benzothiophenel, dibenzothiophenel, thienozothiophenel, benzofuranyl, phenanthrolinel, isoxazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, silanyl, dibenzofuranyl, and N-arylcarbazolyl (such as N-phenylcarbazolyl), N-heteroarylcarbazolyl (such as N-pyridylcarbazolyl), and N-alkylcarbazolyl (such as N-methylcarbazolyl), etc. Among these, thiophenel, furanyl, and phenanthrolinel are heteroaryl groups of the single aromatic ring type, while N-arylcarbazolyl and N-heteroarylcarbazolyl are heteroaryl groups of the polycyclic system type linked by carbon-carbon conjugation.

[0024] In embodiments of this disclosure, the substituted heteroaryl group may be one or more hydrogen atoms of the heteroaryl group that are replaced by groups such as deuterium atoms, halogen groups, -CN, aryl, heteroaryl, trialkylsilyl, alkyl, cycloalkyl, alkoxy, alkylthioyl, etc. Specific examples of aryl-substituted heteroaryl groups include, but are not limited to, phenyl-substituted dibenzofuranyl, phenyl-substituted dibenzothiophenyl, phenyl-substituted pyridyl, etc. It should be understood that the number of carbon atoms in the substituted heteroaryl group refers to the total number of carbon atoms of the heteroaryl group and the substituents on the heteroaryl group.

[0025] In this embodiment of the disclosure, a non-positioned connecting key refers to a single bond extending from the ring system. The term "" indicates that one end of the linker bond can connect to any position in the ring system that the bond penetrates, while the other end connects to the rest of the compound molecule.

[0026] For example, as shown in equation (f) below, the naphthyl group represented by equation (f) is connected to other positions of the molecule through two non-positional linkages that span the bicyclic ring. This means that any possible connection mode is shown in equations (f-1) to (f-10).

[0027] .

[0028] For another example, as shown in the following formula (X'), the phenanthrene group represented by formula (X') is connected to other positions of the molecule through a non-positional linker extending from the middle of one side of the benzene ring. This means that any possible connection mode shown in formulas (X'-1) to (X'-4) can be represented.

[0029] .

[0030] In the embodiments of this disclosure, a non-positional substituent refers to a substituent connected by a single bond extending from the center of the ring system, indicating that the substituent can be attached to any possible position in the ring system. For example, as shown in the following formula (Y), the substituent R' group represented by formula (Y) is connected to the quinoline ring by a non-positional linking bond, which means that it includes any possible connection mode shown in formulas (Y-1) to (Y-7).

[0031] .

[0032] This disclosure provides a metal complex, the chemical structural formula of which is shown in Formula 1:

[0033] Wherein, L1 is selected from alkyl groups having 1 to 3 carbon atoms, whether single-bonded, substituted, or unsubstituted; M is selected from iridium, platinum, ruthenium, osmium, copper, and gold; RA is selected from substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted fused aromatic heterocycles; RB is selected from substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic heterocycles, and RB has at least one SP. 2 Hybridized N; RC is selected from substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted fused aromatic heterocycles; X1 and X2 are each independently selected from C or N; n is selected from 1, 2, or 3; The chemical structural formula of Ar is shown in Formula 2 or Formula 3:

[0034] Among them, X3 is selected from O, S, Se, N, N(R1), C(R2R3), and C(O); RD is selected from substituted or unsubstituted aromatic rings, substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic rings, and substituted or unsubstituted fused aromatic heterocycles. RE is selected from substituted or unsubstituted aromatic rings, substituted or unsubstituted aromatic heterocycles, substituted or unsubstituted fused aromatic rings, and substituted or unsubstituted fused aromatic heterocycles. R1, R2 and R3 are each independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl groups having 1 to 3 carbon atoms, or substituted or unsubstituted aryl groups having 6 to 12 carbon atoms; When L1, R1, R2, R3, RA, RB, RC, RD, or RE has substituents, the number of substituents is one or more, and each substituent is independently selected from deuterium, halogen, alkyl, alkoxy, aryloxy, alkylamino, arylamino, benzyloxy, benzylimino, or two adjacent substituents are connected to each other to form a 3- to 10-membered ring.

[0035] The metal complexes disclosed herein can be used as sensitizing materials in organic electroluminescent devices, for example, as doping in organic light-emitting layers. These metal complexes possess the ability to capture singlet and triplet excitons, transferring exciton energy to the light-emitting material (e.g., to the dopant material of the organic light-emitting layer), thereby achieving 100% internal quantum efficiency. The metal complexes disclosed herein have a carbonyl group complexed with metal M, and simultaneously possess groups shown in Formula 2 or Formula 3, which can significantly enhance the spin-orbit coupling of the metal complex and increase luminous efficiency. Furthermore, the presence of groups shown in Formula 2 or Formula 3 can enhance the rigidity of the metal complex, thereby reducing non-radiative transitions. Thus, these metal complexes can improve the performance of organic electroluminescent devices, for example, by reducing the driving voltage of the organic electroluminescent device and increasing its luminous efficiency.

[0036] In one embodiment of this disclosure, RA is selected from the group consisting of: ; Where a is the M connection site and b is the L1 connection site.

[0037] In one embodiment of this disclosure, RB is selected from the group consisting of: ; Where c is the connection site of M and d is the connection site of RC.

[0038] In one embodiment of this disclosure, RC is selected from the group consisting of: ; Where e is the connection site of M and f is the connection site of RB.

[0039] In one embodiment of this disclosure, L1 is selected from single bonds, methylene, or deuterated methylene.

[0040] In one embodiment of this disclosure, R1 is selected from phenyl.

[0041] In one embodiment of this disclosure, R2 and R3 are selected from hydrogen or deuterium.

[0042] In one embodiment of this disclosure, the metal M is Pt.

[0043] In one embodiment of this disclosure, RD is selected from substituted or deuterated benzene rings, substituted or deuterated quinoline rings, substituted or deuterated dihydroquinoline rings, and substituted or deuterated benzimidazole rings.

[0044] In one embodiment of this disclosure, RE is selected from substituted or deuterated benzene rings, substituted or deuterated naphthyl rings, substituted or deuterated quinoxaline rings, substituted or deuterated benzothiazole rings, substituted or deuterated benzodioxane-pentene rings, and substituted or deuterated (benzylimine-N-yl)benzene rings.

[0045] In one embodiment of this disclosure, formula 2 is selected from the group consisting of the following structures: .

[0046] In one embodiment of this disclosure, formula 3 is selected from the group consisting of the following structures: .

[0047] In one embodiment of this disclosure, the metal complex is selected from the group consisting of: .

[0049] This disclosure also provides an organic electroluminescent device having an organic light-emitting layer, the organic light-emitting layer having a host material, a sensitizing material, and a doping material; wherein the sensitizing material includes the metal complex provided in this disclosure.

[0050] In one embodiment of this disclosure, the sensitizing material in the organic light-emitting layer is composed of a metal complex provided in this embodiment. For example, the organic light-emitting layer contains 10% to 30% by mass of a metal complex, which serves as the sensitizing material in the organic light-emitting layer.

[0051] In another embodiment of this disclosure, the sensitizing material further includes a TADF (thermally activated delayed fluorescence) material, and the mass of the metal complex is 0.01 to 1.5 times the mass of the TADF material. Thus, the sensitizing material in the organic light-emitting layer includes the metal complex and TADF material provided in this disclosure.

[0052] In one embodiment of this disclosure, see Figure 1 and Figure 2 An organic light-emitting diode (OLED) includes an anode (AE), a light-emitting functional layer (EFL), and a cathode (CE) stacked sequentially. The anode (AE) and cathode (CE) provide charge carriers such as electrons and holes to the light-emitting functional layer (EFL), enabling the EFL to emit light.

[0053] In one embodiment of this disclosure, see Figure 1 The light-emitting functional layer (EFL) includes a light-emitting stack structure (ELS). In another embodiment, see [link to embodiment]. Figure 2The light-emitting functional layer (EFL) includes multiple light-emitting stacked structures (ELS) stacked together, and a charge generation layer (CGL) is disposed between any two adjacent light-emitting stacked structures (ELS). The charge generation layer (CGL) can improve the electron-hole separation efficiency and provide electrons to one of the adjacent light-emitting stacked structures (ELS) and holes to the other adjacent light-emitting stacked structure (ELS) to drive the adjacent light-emitting stacked structures (ELS) to emit light.

[0054] exist Figure 2 In the example, the organic light-emitting device (OLED) includes two stacked light-emitting structures (ELS) and a charge-generating layer (CGL) located between the two ELS. It is understood that the number of ELS in the OLED of this disclosure is not limited to two; for example, it can be one to five, such as one, two, three, four, or five. Between any two adjacent ELS, the OLED can have a charge-generating layer (CGL) to drive the two ELS.

[0055] In one embodiment of this disclosure, see Figure 1 and Figure 2 The light-emitting stacked structure (ELS) includes a hole transport region (HTA), an organic light-emitting layer (EML), and an electron transport region (ETA) stacked sequentially. The HTA is located on the side of the EML closer to the anode (AE), and the ETA is located on the side of the EML closer to the cathode (CE). The anode (AE) or the charge generation layer (CGL) injects holes into the EML through the HTA. The HTA can be adjusted to regulate the injection process, such as adjusting the hole injection rate, efficiency, and energy level. Similarly, the cathode (CE) or the CGL injects electrons into the EML through the ETA. The ETA can also be adjusted to regulate the injection process, such as adjusting the electron injection rate, efficiency, and energy level. Thus, the HTA and ETA improve the balance between hole and electron injection, enhancing the performance of the OLED (Organic Light-Emitting Device).

[0056] Optionally, the hole transport region (HTA) may include one or more of the following: a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL). Depending on the requirements, the hole transport region (HTA) may have one or more hole transport layers (HTL), or a light-emitting auxiliary layer may be used to replace the electron blocking layer (EBL).

[0057] Optionally, the electron transport region (ETA) may include one or more of the electron injection layer (EIL), electron transport layer (ETL), and hole blocking layer (HBL). Depending on the needs, the ETA may have one or more electron transport layers (ETL).

[0058] Optionally, the structures of any two light-emitting stacked structures (ELS) can be the same or different. For example, in Figure 2 In the example, the first stacked structure layer ELS1 includes a hole injection layer HIL, a first hole transport layer HTL1, a first electron blocking layer EBL1, a first organic light-emitting layer EML1, a first hole blocking layer HBL1, and a first electron transport layer ETL1, which are sequentially stacked along the direction from the anode AE ​​to the cathode CE. The hole injection layer HIL, the first hole transport layer HTL1, and the first electron blocking layer EBL1 together form the hole transport region HTA of the first stacked structure layer ELS1, and the first hole blocking layer HBL1 and the first electron transport layer ETL1 together form the electron transport region ETA of the first stacked structure layer ELS1. Figure 2 In the example, the second stacked structure layer ELS2 includes a second hole transport layer HTL2, a second electron blocking layer EBL2, a second organic light-emitting layer EML2, a second hole blocking layer HBL2, a second electron transport layer ETL2, and an electron injection layer EIL, which are sequentially stacked along the direction from the anode AE ​​to the cathode CE. The second hole transport layer HTL2 and the second electron blocking layer EBL2 together constitute the hole transport region HTA of the second stacked structure layer ELS2, and the second hole blocking layer HBL2, the second electron transport layer ETL2, and the electron injection layer EIL together constitute the electron transport region ETA of the second stacked structure layer ELS2.

[0059] In one example, see Figure 2 The charge generation layer CGL comprises an N-type charge generation layer NCGL and a P-type charge generation layer PCGL stacked sequentially. The N-type charge generation layer NCGL is adjacent to the electron transport region ETA of the light-emitting stacked structure ELS to provide electrons to the electron transport region ETA. The P-type charge generation layer PCGL is adjacent to the hole transport region HTA of the light-emitting stacked structure ELS to provide holes to the hole transport region HTA.

[0060] In one embodiment of this disclosure, the anode AE ​​includes an anode material, optionally a material with a high work function that facilitates hole injection into the light-emitting functional layer EFL. Specific examples of anode materials include, but are not limited to: metals such as nickel, platinum, vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; or conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylidene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline. Optionally, a transparent electrode comprising indium tin oxide (ITO) as the anode may be included.

[0061] In some examples, the anode AE ​​can be a single-layer material layer, such as an ITO layer or an IZO layer.

[0062] In other examples, the anode AE ​​may include multiple stacked subelectrode layers, such as stacked ITO / Ag / ITO layers, or stacked Ag / IZO layers, or stacked CNT / ITO layers, or stacked CNT / IZO layers, or stacked GO / ITO layers, or stacked GO / IZO layers.

[0063] In one embodiment of this disclosure, the hole injection layer HIL can be an organic material layer, an inorganic material layer, or a mixed film layer of organic and inorganic materials. Optionally, the inorganic materials used in the hole injection layer HIL include, but are not limited to, molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide. Optionally, the organic materials used in the hole injection layer HIL can include, but are not limited to, benzidine derivatives, starburst aryl amine compounds, phthalocyanine derivatives, or other materials, especially organic compounds with strong electron-withdrawing systems (e.g., F4TCNQ, HATCN, etc.).

[0064] In one embodiment of this disclosure, the thickness of the hole injection layer HIL can be in the range of 5 nm to 30 nm, for example, the thickness of the hole injection layer HIL can be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm or 20 nm.

[0065] In one embodiment of this disclosure, the material of the hole transport layer (HTL) can be selected from carbazole polymers, carbazole-linked triarylamine compounds, or other types of compounds, such as NPB, TPD, BAFLP, DFLDPBi, etc.

[0066] In one embodiment of this disclosure, the thickness of the hole transport layer (HTL) can be 50 nm to 200 nm, particularly 50 nm to 90 nm. For example, the thickness of the hole transport layer (HTL) is 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, or 90 nm.

[0067] In one embodiment of this disclosure, the electron blocking layer (EBL) can be made of carbazole polymer, carbazole-linked triarylamine compound, or other feasible structures. Optionally, the thickness of the EBL can vary for organic light-emitting devices of different colors, and the EBL can be matched with the energy level of the organic light-emitting layer to achieve a light-emitting auxiliary function.

[0068] In one embodiment of this disclosure, the thickness of the hole blocking layer HBL can be 5 nm to 100 nm, especially 5 to 45 nm.

[0069] Optionally, the hole blocking layer HBL has a thickness of 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, or 45nm.

[0070] In one embodiment of this disclosure, if the organic light-emitting device (OLED) is a red-light organic light-emitting device (OLED), then the organic light-emitting layer (EML) is a red-light organic light-emitting layer (EML), and the red-light organic light-emitting layer (EML) includes a red light host material, a sensitizing material, and a red light doping material.

[0071] In one example, the red light doping material has a doping ratio of 1% to 4%. For example, the red light doping material has a doping ratio of 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, or 4%.

[0072] In one example, the red light host material includes a red light P-type host material and a red light N-type host material.

[0073] In one example, the red doped material can be a metal complex, such as Ir(piq)2(acac), PtOEP, Ir(btp)2(acac), etc.

[0074] In one embodiment of this disclosure, the organic light-emitting device (OLED) is a green organic light-emitting device (OLED), and the organic light-emitting layer (EML) is a green organic light-emitting layer (EML). The green organic light-emitting layer (EML) includes a green light host material, a sensitizing material, and a green light doping material.

[0075] In one example, the green light-doping material has a doping ratio of 8% to 10%. For example, the doping ratio of the green light-doping material is 8%, 8.2%, 8.4%, 8.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8%, or 10%.

[0076] Optionally, the host material of the green organic light-emitting layer can be selected from coumarin dyes, quinacrine copper derivatives, polycyclic aromatic hydrocarbons, diamine anthracene derivatives, carbazole derivatives, such as DMQA, BA-NPB, Alq3, etc. The guest material can be metal complexes, such as Ir(ppy)3, Ir(ppy)2(acac), etc.

[0077] In one embodiment of this disclosure, the organic light-emitting device (OLED) is a blue light organic light-emitting device (OLED), and the organic light-emitting layer (EML) is a blue light organic light-emitting layer (EML). The blue light organic light-emitting layer (EML) includes a blue light host material, a sensitizing material, and a blue light doping material.

[0078] In one example, the doping ratio of the blue light-emitting material is 1% to 5%. For example, the doping ratio of the blue light-emitting material is 1%, 1.4%, 1.8%, 2.2%, 2.6%, 3%, 3.4%, 3.8%, 4.2%, 4.6%, or 5%.

[0079] Optionally, the host material of the blue organic light-emitting layer can be selected from anthracene derivatives such as ADN and MADN; the guest material can be pyrene derivatives, fluorene derivatives, perylene derivatives, styrene-amine derivatives, metal complexes, etc., such as TBPe, BDAVBi, DPAVBi, FIrpic, etc.

[0080] In one embodiment of this disclosure, the thickness of the organic light-emitting layer (EML) can be 10 nm to 100 nm, particularly 20 nm to 40 nm. For example, the thickness of the organic light-emitting layer (EML) can be 20 nm, 24 nm, 28 nm, 32 nm, 36 nm, or 40 nm.

[0081] In one embodiment of this disclosure, the hole blocking layer HBL can be an imidazole derivative such as benzimidazole derivative, imidazopyridine derivative, or benzimidazolephenanthridine derivative, or a pyrimidine derivative or triazine derivative, or a compound containing a nitrogen-containing six-membered ring structure such as quinoline derivative, isoquinoline derivative, or phenanthrene derivative (including compounds with phosphine oxide substituents on heterocycles).

[0082] In one embodiment of this disclosure, the thickness of the hole blocking layer HBL can be 5 nm to 10 nm.

[0083] In one example, the hole blocking layer HBL has a thickness of 5nm, 6nm, 7nm, 8nm, 9nm, or 10nm.

[0084] In one embodiment of this disclosure, the electron transport layer (ETL) may include one or more electron transport materials. The electron transport materials may be selected from, but are not limited to, imidazole derivatives such as benzimidazole derivatives, imidazopyridine derivatives, and benzimidazolephenanthridine derivatives; pyrimidine derivatives, triazine derivatives, and other azine derivatives; compounds containing a nitrogen-containing six-membered ring structure such as quinoline derivatives, isoquinoline derivatives, and phenanthreneroline derivatives (including compounds with phosphine oxide substituents on heterocycles, oxadiazole derivatives, quinoxaline derivatives, lithium fluoride, zinc oxide, or other electron transport materials).

[0085] In one example, the electron transport layer (ETL) comprises a host material and a dopant material, wherein the dopant material is lithium quinoxaline or lithium fluoride.

[0086] In one example, the doping ratio of the doped material in the electron transport layer (ETL) is 40% to 60%.

[0087] In one embodiment of this disclosure, the thickness of the electron transport layer (ETL) can be 10 nm to 40 nm, particularly 20 nm to 35 nm. For example, the thickness of the ETL can be 20 nm, 23 nm, 26 nm, 29 nm, 32 nm, or 35 nm.

[0088] In one embodiment of this disclosure, the electron injection layer (EIL) may include inorganic materials such as alkali metal sulfides and alkali metal halides, or may include complexes of alkali metals and organic materials. For example, the material of the electron injection layer (EIL) may be LiQ, lithium fluoride, ytterbium, magnesium, calcium, etc.

[0089] In one embodiment of this disclosure, the thickness of the electron injection layer (EIL) can be 0.5 nm to 3 nm, for example, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm or 3 nm.

[0090] In one embodiment of this disclosure, the cathode CE may include a cathode material that has a small work function and facilitates electron injection into the functional layers. Specific examples of cathode materials include, but are not limited to, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; or multilayer materials such as LiF / Al, Liq / Al, LiO2 / Al, LiF / Ca, LiF / Al, and BaF2 / Ca. Optionally, a metal electrode containing aluminum may be included as the cathode. In one example, the cathode material may be a magnesium-silver alloy.

[0091] This disclosure also provides a display panel comprising an array of organic electroluminescent devices. At least a portion of these organic electroluminescent devices are the organic electroluminescent devices provided in this disclosure. Since this display panel possesses any of the organic electroluminescent devices described in the above embodiments, it has the same beneficial effects, and will not be repeated here.

[0092] The following examples illustrate the preparation process of metal complexes and the structure and performance of organic electroluminescent devices.

[0093] Synthesis Example 1: Preparation of Compound H-1

[0094] Synthesis of intermediate H-1-A

[0095] Under nitrogen atmosphere, 40 g (0.2 mol) of starter 1, 31 g (0.25 mol) of starter 2, 41.46 g (0.3 mol) of anhydrous potassium carbonate, and toluene / water (800 mL / 300 mL) were added sequentially, followed by stirring. Then, 5.78 g (5 mol%) of Pd(PPh3)4 was added at 40 °C, and the mixture was stirred at 80 °C for 12 hours. After the reaction was complete, the organic layer was extracted with dichloromethane, magnesium sulfate was added, and the mixture was filtered. After removing the solvent from the filtered organic layer, column chromatography was used to separate the residue, yielding 30 g (72% yield) of the target intermediate H-1-A. The measured value of intermediate H-1-A was m / Z = 192 (APCI source, [M+H)). + ).

[0096] Synthesis of intermediate H-1-B

[0097] A catalytic amount of Ni nanoparticle suspension (0.0100 mol) was added to a toluene (1.0 L) solution of intermediate H-1-A (38 g, 0.2 mol). Then, feedstock 3 (50 g, 0.250 mol) was added, and the reaction mixture was stirred at 80 °C for 18 h, followed by quenching with ethyl acetate (1.0 L) and n-hexane (1.0 L). The resulting mixture was poured directly onto a short silica gel column, and the eluent was collected and concentrated to give intermediate H-1-B (32.1 g, 94% yield). The measured value of intermediate H-1-B, m / Z, was 324.1 (APCI source, [M+H)). + ).

[0098] Synthesis of compound H-1

[0099] Intermediate H-1-B (2.6 g, 7.98 mmol, 1 equiv), starting material 4 (1 g, 7.98 mmol, 1 equiv), and platinum dichloride 2.55 g (9.57 mmol, 1.2 equiv) were sequentially added to a dry three-necked flask equipped with a magnetic stir bar. The flask was evacuated and backfilled with nitrogen, and the evacuation and backfilling process was repeated twice. Then, DMF (65 mL) was added, and the mixture was stirred at 120 °C for 3 days under a nitrogen atmosphere. After the reaction was complete, the mixture was cooled to room temperature, extracted three times with dichloromethane, dried on Na2SO4, filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 4:1-2:1) to obtain the desired product as a yellow solid, 3.32 g, in 32% yield. The measured value of compound H-1 was m / Z = 641 (APCI source, [M+H)). + ).

[0100] In Synthetic Examples 2-7, compounds H-5, H-17, H-21, H-22, H-25, and H-27 were prepared, respectively, following the preparation process of compound H-1 in Synthetic Example 1. The raw materials 1-4 used in Synthetic Examples 2-7, and the mass spectrometry data of the prepared compounds, are shown in Table 1.

[0101] Table 1: Raw materials and mass spectrometry data for synthesis examples 2-7

[0102] In Table 1 above, the m / z data is from the APCI source [M+H]. + data.

[0103] Device Example 1

[0104] Organic light-emitting devices (test device OLED1) were fabricated using the following method.

[0105] (1) ITO cleaning: Rub the ITO substrate with a lint-free cloth soaked in detergent, then put it into detergent, propanol, acetone and isopropanol respectively and sonicate for 15 minutes each, blow it dry with N2, and put it into the Plasma treatment machine for 15 minutes.

[0106] (2) Vapor deposition of the hole injection layer: The glass plate with the ITO anode is placed in a vacuum chamber and the vacuum is evacuated to <1×10 -5 Pa, a 10 nm hole injection layer (material is compound HI) is vacuum-deposited on the above anode layer.

[0107] (3) Deposition of hole transport layer: 70 nm of compound HT was deposited on the hole injection layer as a hole transport layer at a deposition rate of 0.1 nm / s.

[0108] (4) Electron blocking layer: 10 nm of compound EB was deposited on the hole transport layer as an electron blocking layer at a deposition rate of 0.1 nm / s.

[0109] (5) Evaporation of organic light-emitting layer: The host material, sensitizing material, and dopant material are vapor-deposited on the electron blocking layer to form an organic light-emitting layer. The host material is a 1:1 mixture of compound PH and compound NH. The dopant material is compound DP with a doping amount of 1%; the sensitizing material has a doping amount of 20% and is compound H-1.

[0110] (6) Hole blocking layer: 5 nm of compound NH is deposited on the organic light-emitting layer as a hole blocking layer.

[0111] (7) Electron transport layer: 30 nm of compound ET (doped with 1.5% Liq) is deposited on the hole blocking layer as an electron transport layer.

[0112] (8) A 1 nm layer of compound LiF was vacuum-deposited on the electron transport layer as an electron injection layer at a deposition rate of 0.1 nm / s.

[0113] (9) A 150 nm thick layer of metallic aluminum is vacuum-deposited on the electron injection layer as a cathode at a deposition rate of 1 nm / s to obtain the organic electroluminescent device.

[0114] The structural formulas of the compounds used in the above preparation process are as follows:

[0115] In Device Examples 2-9, test devices OLED2-OLED7, control devices OLEDR1, and control devices OLEDR2 were prepared according to the preparation method shown in Device Example 1. Test devices OLED2-OLED7, control devices OLEDR1, and control devices OLEDR2 have the same structure and preparation process as test device OLED1, the only difference being the material of the organic light-emitting layer.

[0116] The only difference between the test device OLED2 and the test device OLED1 is that the sensitizing material is compound H-5.

[0117] The only difference between the OLED3 and OLED1 test devices is that the sensitizing material is compound H-17.

[0118] The only difference between the OLED4 and OLED1 test devices is that the sensitizing material is a mixture of compound H-21 and compound A (a TADF material) in a 1:1 ratio.

[0119] The only difference between the OLED5 and OLED1 test devices is that the sensitizing material is a mixture of compound H-22 and compound A (a TADF material) in a 1:1 ratio.

[0120] The only difference between the OLED6 and OLED1 test devices is that the sensitizing material is compound H-25 and does not contain any doped material, while the doping ratio of the sensitizing material is 20%.

[0121] The only difference between the OLED7 and OLED1 test devices is that the sensitizing material is compound H-27 and does not contain any doped material, while the doping ratio of the sensitizing material is 20%.

[0122] The only difference between the control device OLEDR1 and the test device OLED1 is that the sensitizing material is compound B1 (a sensitizer).

[0123] The only difference between the control device OLEDR2 and the test device OLED1 is that the sensitizing material is compound B2 (a sensitizer).

[0124]

[0125] The driving voltage and luminous efficiency of each test device (OLED1~OLED7) and control devices (OLEDR1 and OLEDR2) were tested, and the test results were normalized. The test results are shown in Table 2.

[0126] Table 2: Test Results of Test Device and Control Device

[0127] As shown in Table 2, the metal complex provided in this disclosure, when added as a sensitizing material to the organic light-emitting layer, can effectively reduce the driving voltage of the organic electroluminescent device and improve its luminous efficiency. Furthermore, its performance in reducing driving voltage and improving luminous efficiency is comparable to or even better than existing sensitizing materials. Moreover, when the metal complex of this disclosure is mixed with TADF material as a sensitizing material, it can further reduce the driving voltage of the organic electroluminescent device and significantly improve its luminous efficiency.

[0128] According to the test data in Table 2, the organic light-emitting layer of the organic electroluminescent device provided in this disclosure requires the addition of doping materials (especially phosphorescent doping materials); otherwise, the luminous efficiency of the organic electroluminescent device will be significantly reduced and the driving voltage will be significantly increased. However, the test devices OLED6 and OLED7 still maintain their luminous capabilities without phosphorescent doping materials, indicating that the metal complex provided in this disclosure has a certain phosphorescent self-luminescence capability. Its exciton energy level is similar to that of the doping material, so it is speculated that the metal complex can effectively synergize with the phosphorescent doping material, thereby improving the luminous efficiency.

[0129] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A metal complex characterized in that, The chemical structure of the metal complex is shown as Formula 1: L1 is selected from a single bond, a substituted or unsubstituted alkyl group with 1-3 carbon atoms; M is selected from iridium, platinum, ruthenium, osmium, copper, gold; RA is selected from a substituted or unsubstituted aromatic heterocycle, a substituted or unsubstituted fused aromatic heterocycle; RBis selected from substituted or unsubstituted aromatic heterocycle, substituted or unsubstituted fused aromatic heterocycle, and RBhas at least one SP 2 hybridized N; RC is selected from a substituted or unsubstituted aromatic heterocycle, a substituted or unsubstituted fused aromatic heterocycle; X1 and X2 are each independently selected from C or N; n is selected from 1, 2 or 3; The chemical structure of Ar is shown as Formula 2 or Formula 3: X3 is selected from O, S, Se, N, N(R1), C(R2R3), C(O); RD is selected from a substituted or unsubstituted aromatic ring, a substituted or unsubstituted aromatic heterocycle, a substituted or unsubstituted fused aromatic ring, a substituted or unsubstituted fused aromatic heterocycle; RE is selected from a substituted or unsubstituted aromatic ring, a substituted or unsubstituted aromatic heterocycle, a substituted or unsubstituted fused aromatic ring, a substituted or unsubstituted fused aromatic heterocycle; R1, R2 and R3 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group with 1-3 carbon atoms, a substituted or unsubstituted aryl group with 6-12 carbon atoms; When L1, R1, R2, R3, RA, RB, RC, RD or RE has a substituent, the number of the substituent is one or more, and each is independently selected from deuterium, halogen, an alkyl group with 1-3 carbon atoms, an alkoxy group, an aryloxy group, an alkylamine group, an arylamine group, a benzyloxy group, a benzylimine group, or two adjacent substituents are connected to each other to form a 3-10 membered ring.

2. Metal complex according to claim 1, characterized in that RA is selected from the group consisting of: ； wherein a is the connection site of M, and b is the connection site of L1.

3. The metal complex according to claim 1, characterized by RB is selected from the group consisting of: ； wherein c is the connection site of M, and d is the connection site of RC.

4. The metal complex of claim 1, wherein RC is selected from the group consisting of: ； wherein e is the connection site of M, and f is the connection site of RB.

5. The metal complex of claim 1, wherein RD is selected from a substituted or deuterium-substituted benzene ring, a substituted or deuterium-substituted quinoline ring, a substituted or deuterium-substituted dihydroquinoline ring, a substituted or deuterium-substituted benzimidazole ring.

6. The metal complex of claim 1, wherein RE is selected from a substituted or deuterium-substituted benzene ring, a substituted or deuterium-substituted naphthalene ring, a substituted or deuterium-substituted quinoxaline ring, a substituted or deuterium-substituted benzothiazole ring, a substituted or deuterium-substituted benzodioxole ring, a substituted or deuterium-substituted (benzylideneimine-N-yl) benzene ring.

7. The metal complex of claim 1, wherein Formula 2 is selected from the group consisting of: ； Formula 3 is selected from the group consisting of: 。 8. The metal complex of claim 1, wherein, The metal complex is selected from the group consisting of: 。 9. An organic electroluminescent device, characterized by The organic electroluminescent device has an organic light-emitting layer, and the organic light-emitting layer has a host material, a sensitizing material and a doping material; wherein the sensitizing material comprises the metal complex according to any one of claims 1-8.

10. The organic electroluminescent device according to claim 9, characterized in that, The sensitizing material further comprises a TADF material, and the mass of the metal complex is 0.01-1.5 times the mass of the TADF material.

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