A phosphorescent organic electroluminescent material and a light-emitting device

Abstract

The present invention belongs to the technical field of electroluminescent devices, and specifically discloses a phosphorescent organic electroluminescent material, and also relates to an organic electroluminescent device prepared therefrom. The phosphorescent organic electroluminescent material provided by the present invention uses a dual host material and a specific dopant material as the light-emitting layer material together. The combination of the specific host material and the specific dopant material can obtain a suitable energy level matching, making the concentration of carriers in the light-emitting layer more balanced, thereby improving the comprehensive performance of the organic electroluminescent device.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescent devices, and specifically discloses a phosphorescent organic electroluminescent material, and also discloses an electroluminescent device including the phosphorescent organic electroluminescent material. Background Art

[0002] Organic electroluminescence (OLED) refers to the electroluminescent phenomenon of organic materials under the excitation of current or electric field. The device made according to this principle is called an organic electroluminescent device. Compared with the current common flat panel display technologies such as field emission display (FED), liquid crystal display (LCD), and plasma display (PDP), the organic electroluminescent device has the following characteristics: The material uses organic substances / polymers, so the selection range is wide, and any color display from red light to blue light can be realized; the driving voltage is low, the luminous brightness and luminous efficiency are high, and a flexible display device can be made; the response speed is fast and the viewing angle is wide; the device is ultra-thin, small in volume and light in weight; more importantly, the organic light-emitting materials provide a wide range for material selection with their inherent diversity. Through the design, assembly and tailoring of the organic molecular structure, various different needs can be met and large-area display is easy to achieve.

[0003] Generally speaking, a typical OLED device structure is formed by inserting one or more ultra-thin organic semiconductor films between the cathode and the anode. At present, most small molecule device structures adopt a multi-layer film structure, and each layer has a special function. According to different functions, the organic films can be divided into a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and the corresponding organic materials are hole injection materials, hole transport materials, electron blocking materials, host materials and doping materials, hole blocking materials, electron transport materials and electron injection materials respectively. When an electric field is applied between the ITO anode with high light transmittance and the metal cathode with high reflectivity, holes will be injected from the anode with a higher work function and electrons will be injected from the cathode with a lower work function into the adjacent organic materials respectively. The injected holes and electrons migrate under the drive of the applied electric field and finally meet and recombine in the light-emitting layer to form excitons. Next, the excitons diffuse in the organic layer and experience a radiative process to emit light.

[0004] As is well known, the light-emitting layer of a phosphorescent OLED device is composed of a host material and a dopant material. The host light-emitting material transfers energy to the guest light-emitting material, and the guest light-emitting material regulates the color to emit light. Therefore, commercially, phosphorescent devices with characteristics such as higher efficiency, more saturated emission spectra, and longer service life are expected. The host material and the dopant material must meet the following conditions: 1. The triplet energy level of the host material should be higher than that of the dopant material; 2. There should be a good overlap between the emission spectrum of the host material and the absorption spectrum of the dopant material; 3. Good thermal stability; 4. The HOMO / LUMO of the host material should be able to contain the HOMO / LUMO energy levels of the dopant material and match the energy levels of the adjacent functional layer materials; 5. The host material has a high carrier mobility and good carrier balance. In summary, selecting a suitable combination of host material and dopant material is crucial for obtaining high-performance OLED phosphorescent devices.

[0005] Existing phosphorescent OLED devices generally have shortcomings such as short lifespan and poor luminous efficiency. The present invention intends to propose a novel phosphorescent organic electroluminescent material by studying the light-emitting layer materials to improve the performance of organic electroluminescent devices. Summary of the Invention

[0006] The object of the present invention is to develop a phosphorescent organic electroluminescent material, which uses a dual-host material and a specific dopant material as the light-emitting layer material together. The combination of the specific host material and the specific dopant material can obtain a suitable energy level matching, make the concentration of carriers in the light-emitting layer more balanced, and thus improve the comprehensive performance of the organic light-emitting device.

[0007] Specifically, in a first aspect, the present invention provides a phosphorescent organic electroluminescent material, comprising: a host material and a dopant material, wherein the host material comprises a first host compound and a second host compound;

[0008] The first host compound, the second host compound, and the dopant material have structures represented by general formula (I), general formula (II), and general formula (III), respectively:

[0009]

[0010] In general formula (I), Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C 60 aryl groups, Ar1 and Ar2 may be the same or different; Ar3 is selected from substituted or unsubstituted C1-C6 alkylene groups, C6-C 60 arylene groups, m is 0 or 1; Rp1 and Rp2 each represent a substitution group from single substitution to the maximum allowable substitution number, and Rp1 and Rp2 are each independently selected from hydrogen, deuterium, halogen, amino group, C1-C 20 chain alkyl groups, C3-C20 Naphthenyl, C3-C 20 Alkoxy, C3-C 20 Silyl, C3-C 20 Alkylamino, C6-C 60 Arylamino, C3-C 60 Heteroarylamino, C6-C 60 Aryl, C3-C 60 A combination of one or more of heteroaryl; Rp1 and Rp2 can each independently fuse with the connected benzene ring to form a ring or not form a ring;

[0011] In general formula (II), X is selected from O, S or Se; Y1, Y2, Y3 are each independently selected from N or CH, Y1, Y2, Y3 are the same or different, and Y1, Y2, Y3 are not simultaneously CH; RN1, RN2, RN3 each independently represent hydrogen, phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, at least one hydrogen in the phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl can be further substituted by deuterium, C1-C4 alkyl or phenyl, RN1, RN2, RN3 are the same or different, and when RN1 is hydrogen, RN2 and RN3 are not simultaneously hydrogen; RN4 is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, at least one hydrogen in the phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl can be further substituted by deuterium, C1-C4 alkyl or phenyl;

[0012] In general formula (III), Z is selected from O, S or Se; q is 0, 1, 2, 3 or 4; k is 0 or 1; Rc1 and Rc2 are each independently selected from hydrogen, deuterium, halogen, C1-C 20 Linear alkyl, C3-C 20 Naphthenyl, C1-C 20 Alkoxy, C6-C 60 Aryloxy, C1-C 20 Alkylsilyl, C6-C 60 Aryl, C3-C 60 Heteroaryl, when Rc1 and Rc2 are multiple, adjacent Rc1 and Rc2 are connected to form a ring or not connected to form a ring; X1, X2, X3, X4, X5 and X6 are each independently selected from C, CR or N; Rc3-Rc 10 Are each independently selected from hydrogen, deuterium, halogen, C1-C 20 Linear alkyl, C3-C 20 Naphthenyl, C1-C 20 Alkoxy, C6-C 60 Aryloxy, C1-C 20 Alkylsilyl, C6-C 60 Aryl, C3-C 60 Heteroaryl, Rc3-Rc 10Two adjacent ones among them can form a spiro structure through bridging; wherein, C1~C 20 linear alkyl, C3~C 20 cycloalkyl, C1~C 20 alkoxy, C6~C 60 aryloxy, C1~C 20 alkylsilyl, C6~C 60 aryl, C3~C 60 heteroaryl can be further substituted by one or more fluorine atoms or deuterium atoms.

[0013] As a preferred embodiment of the present invention, the first host compound has a structure represented by the general formula (I-1):

[0014]

[0015] In the general formula (I-1), Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6~C 60 aryl, Ar1 and Ar2 may be the same or different; Ar3 is selected from substituted or unsubstituted C1~C6 alkylene, C6~C 60 arylene, m is 0 or 1; Rp1 and Rp2 are each independently selected from hydrogen, deuterium, halogen, C1~C6 linear alkyl, C3~C6 silyl, and deuterated or fluorinated linear alkyl of C1~C6.

[0016] As a further preferred embodiment of the present invention, the first host compound is selected from the following compounds:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] As a preferred embodiment of the present invention, the second host compound has a structure represented by the general formula (II-1), general formula (II-2) or general formula (II-3):

[0024]

[0025] In General Formula (II-1), General Formula (II-2), or General Formula (II-3), X is selected from O; Y1, Y2, and Y3 are each independently selected from N or CH, Y1, Y2, and Y3 are the same or different, and Y1, Y2, and Y3 are not simultaneously CH; RN1, RN2, and RN3 each independently represent hydrogen, phenyl, or deuterated phenyl, RN1, RN2, and RN3 are the same or different, and when RN1 is hydrogen, RN2 and RN3 are not simultaneously hydrogen; RN4 is selected from phenyl, biphenyl, terphenyl, or deuterated phenyl.

[0026] As a further preferred embodiment of the present invention, the second host compound is selected from the compounds having the following structures:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] As a preferred embodiment of the present invention, the doping material is selected from the following compounds:

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043] As a preferred embodiment of the present invention, the phosphorescent organic electroluminescent material provided by the present invention, wherein the mixing mass ratio of the host material and the doping material is (80-99):(1-20), further preferably (90-99):(1-10), for example, the mass ratio can be 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2 or 99:1.

[0044] As a preferred embodiment of the present invention, the mixing mass ratio of the first host compound and the second host compound in the host material is (0.8-1.2):(0.8-1.2), preferably 1:1.

[0045] In a second aspect, the present invention provides an application of the phosphorescent organic electroluminescent material in an organic electroluminescent device.

[0046] Preferably, the application of the phosphorescent organic electroluminescent material in the organic layer of the electroluminescent device.

[0047] More preferably, the application of the phosphorescent organic electroluminescent material in the light-emitting layer of the electroluminescent device, used as the light-emitting layer material.

[0048] As a preferred embodiment of the present invention, calculated based on the total mass of the light-emitting layer material, the mass percentage content of the first host compound in the light-emitting layer material is 40%-50%, the mass percentage content of the second host compound in the light-emitting layer material is 40%-50%, and the mass percentage content of the doping material in the light-emitting layer material is 1%-10%.

[0049] More preferably, the mass percentage content of the first host compound in the light-emitting layer material is 47%-48%, the mass percentage content of the second host compound in the light-emitting layer material is 47%-48%, and the mass percentage content of the doping material in the light-emitting layer material is 4%-6%.

[0050] In a third aspect, the present invention provides an electroluminescent device including the phosphorescent organic electroluminescent material.

[0051] Preferably, the electroluminescent device includes an anode, a cathode, and at least one light-emitting layer disposed between the anode and the cathode, and the light-emitting layer includes the phosphorescent organic electroluminescent material.

[0052] More preferably, in the electroluminescent device, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are disposed between the anode and the cathode, and the light-emitting layer includes the phosphorescent organic electroluminescent material.

[0053] More preferably, in the electroluminescent device, a packaging layer is further provided on the cathode.

[0054] In a fourth aspect, the present invention provides a display component including the electroluminescent device of the present invention.

[0055] The present invention provides a novel phosphorescent organic electroluminescent material. Through the combination of two host materials with specific structures and a dopant material with a specific structure, when used as the luminescent layer material of an electroluminescent device, appropriate energy level matching of the material can be obtained, and the concentration of carriers in the luminescent layer can be effectively regulated to achieve the desired balance. Compared with the prior art, the phosphorescent organic electroluminescent material of the present invention can significantly improve the performance of the organic electroluminescent device. For example, it can improve the voltage, luminous efficiency, and lifespan of the device, etc., making the organic electroluminescent device perform better. Description of the Drawings

[0056] Figure 1 is a schematic diagram of the layered structure of an organic electroluminescent device;

[0057] Figure 2 is a schematic diagram of the layered structure of another organic electroluminescent device. Detailed Embodiments

[0058] The technical solutions of the present invention will be described in detail below.

[0059] Among them, the substrate of the organic electroluminescent device can be glass, metal, plastic, etc. Figure 1 Schematically and non - restrictively shows an organic electroluminescent device 100. It should be noted that the figure is not necessarily drawn to scale, and some layer structures in the figure can also be omitted as needed. Figure 1 The OLED device 100 shown may include a substrate 111, an anode 12, a hole injection layer 13, a hole transport layer 14, an electron blocking layer 15, a luminescent layer 16, a hole blocking layer 17, an electron transport layer 18, an electron injection layer 19, and a cathode 20. The OLED device can be prepared by sequentially depositing the described layers. The properties, functions, and exemplary materials of each layer are described in more detail in columns 6 - 10 of US Patent US7,279,704B2. The entire content of the above - mentioned patent is incorporated herein by reference.

[0060] Each of the above layers has more examples. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated herein by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of host materials are disclosed in U.S. Patent No. 6,303,238, issued to Thompson et al., which is incorporated herein by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of cathodes are disclosed in U.S. Patents Nos. 5,703,436 and 5,707,745, which are incorporated herein by reference in their entirety, and include a composite cathode having a thin layer of a metal such as Mg:Ag and an overlying transparent, conductive, sputter-deposited ITO layer. The principles and use of the barrier layer are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated herein by reference in their entirety. Examples of the injection layer are provided in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety. A description of the protective layer can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety.

[0061] The above-described layered structure is provided by way of non-limiting examples. The functions of the OLED can be achieved by combining the various functional layers described above, or some layers can be completely omitted. It can also include other layers not specifically described. In one embodiment, the OLED can be described as having an "organic layer" disposed between the cathode and the anode. The organic layer can include one or more layers.

[0062] The OLED also requires a packaging layer, as Figure 2 schematically and non-limitingly shows an organic light-emitting device 210, Figure 2 The OLED device 210 shown can include a substrate 111, an anode 120, a hole injection layer 130, a hole transport layer 140, an electron blocking layer 150, a light-emitting layer 160, a hole blocking layer 170, an electron transport layer 180, an electron injection layer 190, and a cathode 200. It is the same as Figure 1In contrast, a encapsulation layer 112 may also be included on the cathode 200 to prevent harmful substances such as moisture and oxygen from the environment. Any material capable of providing an encapsulation function can be used as the encapsulation layer, such as glass or an organic-inorganic hybrid layer. The encapsulation layer should be placed directly or indirectly outside the OLED device. Multilayer thin film encapsulation is described in U.S. Patent US7968146B2, the entire content of which is incorporated herein by reference.

[0063] Devices prepared according to embodiments of the present invention can be incorporated into a variety of consumer products having one or more electronic component modules (or units) with the device. For example: viewfinders, microdisplays, 3-D displays, flat panel displays, monitors, medical monitors, head-up displays, fully or partially transparent displays, flexible displays, vehicle displays, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, smart phones, tablet computers, phablets, wearable devices, smart watches, laptop computers, digital cameras, portable video cameras, taillights, optical sensors, solar cells, lighting elements, organic thin film transistors, organic field effect transistors, organic thin film solar cells, information tags, electronic artificial skin sheets, sheet-type scanners or electronic paper, etc.

[0064] In this specification, C6-C 60 aryl, C3-C 60 heteroaryl, unless otherwise specified, are aromatic groups that satisfy a π-conjugated system, and both monocyclic and polycyclic cases are included. A monocyclic ring refers to a molecule containing at least one phenyl group. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and are connected by single bonds. Exemplarily, such as phenyl, biphenyl, terphenyl, etc.; a polycyclic ring refers to a molecule containing at least two benzene rings, but the benzene rings are not independent of each other, but are fused to each other by sharing ring edges. Exemplarily, such as naphthyl, anthracenyl, phenanthryl, etc.; a monocyclic heteroaryl refers to a molecule containing at least one heteroaryl group. When the molecule contains a heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and other groups are independent of each other and are connected by single bonds. Exemplarily, such as pyridine, furan, thiophene, etc.; a polycyclic heteroaryl refers to a structure formed by fusing at least one phenyl group and at least one heteroaryl group, or, formed by fusing at least two heteroaryl groups. Exemplarily, such as quinoline, isoquinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, etc.

[0065] In this specification, substituted or unsubstituted C6-C 60 aryl is preferably C6-C 30An aryl group, preferably an exemplary aryl group selected from the group consisting of phenyl, naphthyl, anthracenyl, benzanthracenyl, phenanthrenyl, benzophenanthrenyl, pyrenyl, chrysenyl, perylenyl, fluoranthenyl, tetraphenyl, pentaphenyl, benzopyrenyl, biphenyl, terphenyl, triphenyl, tetraphenyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indeno[1,2-b]fluorene, truxene, isotruxene, spirotruxene, spiroisotruxene. The C6-C 60 The aryl group may also be a group formed by combining the above groups through single bonds or / and fusion.

[0066] In this specification, the heterocyclic group includes aryl groups and non-aromatic cyclic groups. Isoaryl also refers to heteroaryl. Preferred non-aromatic heterocyclic groups are those containing 3 to 7 ring atoms, which include at least one heteroatom such as nitrogen, oxygen, and sulfur. The heterocyclic group may also be an aromatic heterocyclic group having at least one heteroatom selected from nitrogen atoms, oxygen atoms, sulfur atoms, and selenium atoms.

[0067] In this specification, the substituted or unsubstituted C3-C 60 The heteroaryl group is preferably a C3-C 30 The heteroaryl group can be a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, a sulfur-containing heteroaryl group, etc. As preferred examples of the heterocycle in the present invention, for example, furyl, thienyl, pyrrolyl, benzofuryl, benzothienyl, isobenzofuryl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl, and derivatives thereof, wherein the carbazolyl derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole, benzocarbazole, dibenzocarbazole, or indolocarbazole. The C3-C 60 The heteroaryl group may also be a group formed by combining the above groups through single bonds or / and fusion.

[0068] In this specification, unless otherwise specified, the alkyl group includes straight-chain alkyl groups, branched-chain alkyl groups, and also includes the concept of cycloalkyl groups. Examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, adamantyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, pentafluoroethyl, 2,2,2-trifluoroethyl, etc.

[0069] In this specification, the cycloalkyl group includes monocyclic cycloalkyl groups and polycyclic cycloalkyl groups. Examples include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0070] In this specification, as the C1-C 20Examples of alkoxy groups include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, etc. Among them, methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, sec-butoxy, isobutoxy, and isopentyloxy are preferred, and methoxy is more preferred.

[0071] In this specification, as the aryloxy group having 6 to C 60 it may be mentioned the groups formed by connecting each of the groups exemplified for the above-mentioned substituted or unsubstituted aryl group having 6 to C 60 to oxygen. Specific examples can be referred to the above examples and will not be elaborated here.

[0072] In this specification, examples of halogens include: fluorine, chlorine, bromine, iodine, etc.

[0073] This application does not limit the preparation method of the organic electroluminescent device. The preparation methods in the following examples are only examples and should not be construed as limitations. Those skilled in the art can reasonably improve the preparation methods in the following examples based on the prior art. The preparation of the light-emitting device in the examples is carried out using conventional equipment in the art and is tested by methods well-known to those skilled in the art. Since those skilled in the art are aware of the relevant content such as the use of the above equipment and the testing methods, and can obtain the inherent data of the samples determinately and without being affected, the above content will not be elaborated further in this patent.

[0074] The technical solutions of the present invention will be further described below through specific examples. The following examples are only used to illustrate the present invention, but not to limit the scope of the present invention. Any equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included within the scope of the claims.

[0075] The present invention does not limit the preparation methods of the first host compound, the second host compound, and the doping material selected. Typically but not restrictively, the following compounds are taken as examples, and their synthesis routes and preparation methods are as follows.

[0076] Synthesis of P-86

[0077]

[0078] The synthesis route is as follows:

[0079]

[0080] The specific operation steps are as follows:

[0081] Under nitrogen protection, 500 mL of tetrahydrofuran and 33.9 g (0.1 mol) of 3-bromo-9-(2-(methyl-d3)phenyl)-9H-carbazole were added to a dry 2 L three-necked flask. Stirring was started, and the temperature was lowered to -78 °C. 500 mL of n-butyllithium was added dropwise. After the addition was complete, triisopropyl borate (28 g, 1.5 mol) was added dropwise while maintaining the temperature, and the reaction was carried out for 2 h. After the reaction was completed, the temperature was raised to 10 °C, and the pH was adjusted to less than 5 by adding 3 M hydrochloric acid solution. The mixture was allowed to stand and separated by liquid separation. The organic phase was separated, extracted, dried, purified by column chromatography, and the solvent was evaporated to obtain 23.7 g of compound P-86-1 with a yield of 78%.

[0082] Under nitrogen protection, P-86-1 (30 g, 0.1 mol), m-dibromobenzene (23.6, 0.1 mol) and 500 mL of tetrahydrofuran were added to a dry 2 L three-necked flask. 27 g of potassium carbonate, 100 mL of deionized water and 1.1 g of tetrakis(triphenylphosphine)palladium were added. Stirring was started, and the mixture was heated to reflux for 12 h. After the reaction was completed, the organic phase was separated, extracted, dried, purified by column chromatography, and the solvent was evaporated to obtain 42.8 g of product P-86 with a yield of 72%.

[0083] Product MS (m / e): 594.; Elemental analysis (C 44 H 26 D6N2): Theoretical value C, 88.85; H, 6.44; N, 4.71; Measured value C, 88.88, H, 6.38, N, 4.73.

[0084] Synthesis of N-7

[0085]

[0086] The synthesis route is as follows:

[0087]

[0088] The specific operation steps are as follows:

[0089] Under nitrogen protection, compound N-7-1 (22.6 g, 0.1 mol), compound N-7-2 (27.3 g, 0.11 mol), sodium tert-butoxide (10.6 g, 0.11 mol), tris(dibenzylideneacetone)dipalladium (4.6 g) and 300 ml of toluene were added to a dry 500 mL three-necked flask. Stirring was started, and the mixture was heated to reflux for 6 h. After the reaction was completed, the temperature was lowered to room temperature, 250 ml of water was added, and the mixture was stirred for 15 min and then filtered to obtain a filtrate. The filtrate was filtered through diatomaceous earth and then separated by liquid separation to obtain an organic phase. The organic phase was extracted, dried, purified by column chromatography, and the solvent was evaporated to obtain 28.5 g of product N-7-3 with a yield of 65%.

[0090] Take 43.8 g (0.1 mol) of the intermediate N-7-3 from the previous step and add it to a 2 L three-necked flask. Then add 500 mL of toluene, 200 mL of ethanol, 100 mL of water, and N-7-4 (29.3 g, 0.1 mol) respectively. After purging with nitrogen three times, add 1 g of tetrakis(triphenylphosphine)palladium and potassium carbonate (27.6 g, 0.2 mol). Start magnetic stirring and heat to reflux for 10 h. After the reaction is completed, cool to room temperature. The reaction solution is subjected to extraction and liquid separation. The organic phase is dried by rotary evaporation and passed through a silica gel column to obtain 47.5 g of solid N-7 with a yield of 73%.

[0091] Product MS (m / e): 650; Elemental analysis (C 45 H 18 D 10 N4O): Theoretical value C, 83.05; H, 5.88; N, 8.61; O, 2.46; Measured value C, 83.21; H, 5.74; N, 8.72.

[0092] Synthesis of I-87

[0093]

[0094] The synthesis route is as follows:

[0095]

[0096]

[0097] The specific synthesis steps are as follows:

[0098] 1. Synthesis of compound I-87-1: In a 1 L three-necked flask equipped with a mechanical stirrer, a reflux condenser and a nitrogen protection device, successively add 2-bromo-5-deuteromethylpyridine (17.5 g, 0.1 mol), deuterophenylboronic acid (12.7 g, 0.1 mol), potassium carbonate (27 g, 0.2 mol), tetrakis(triphenylphosphine)palladium 1.1 g, 400 mL of tetrahydrofuran and 100 mL of water. Heat to reflux and react for 12 hours. After the reaction is completed, separate the organic phase, extract, dry, perform column chromatography, and dry the solvent by rotary evaporation to obtain 12.7 g of the product with a yield of 72%.

[0099] 2. Synthesis of compound I-87-2: In a 1 L three-necked flask equipped with a mechanical stirrer, a reflux condenser and a nitrogen protection device, successively add I-87-1 (17.7 g, 0.1 mol), iridium(III) chloride hydrate (8.8 g, 0.25 mol), ethylene glycol monoethyl ether 450 mL, and distilled water 150 mL. Heat to 130 °C and reflux for 24 hours. After natural cooling, add 100 mL of distilled water, shake, filter by suction, wash with water and then with ethanol. Dry under vacuum to obtain 24.0 g of a yellow solid product with a yield of 83%.

[0100] 3. Synthesis of Compound I-87-3: In a 1 L three-necked flask equipped with a nitrogen protection device, 11.2 g (0.01 mol) of I-87-2 and 200 ml of dichloromethane were successively added. After stirring well, a 30 ml methanol solution of silver trifluoromethanesulfonate (5.1 g, 0.02 mol) was added. The mixture was stirred at room temperature for 24 hours, filtered through diatomaceous earth, and the filtrate was concentrated to dryness to obtain 3.2 g of a yellowish-brown solid with a yield of 42%.

[0101] 4. Synthesis of Compound I-87-4: In a 2 L three-necked flask equipped with mechanical stirring, 200 mL of THF and 22.8 g (0.1 mol) of 6-chloro-3-cyanodibenzofuran were added. Stirring was started, and under nitrogen protection, the temperature was lowered to -78 °C. 60 mL of 2 M n-butyllithium was added dropwise. After stirring for 1 h, deuterated methanol was added, and the mixture was allowed to warm to room temperature naturally. Saturated ammonium chloride solution and 200 mL of ethyl acetate were added, and the organic phase was extracted, dried, purified by column chromatography, and the solvent was concentrated to dryness to obtain 17.4 g of a solid with a yield of 76%.

[0102] 5. Synthesis of Compound I-87-5: In a 1 L three-necked flask equipped with mechanical stirring, 22.9 g (0.1 mol) of I-87-4, 25.4 g (0.1 mol) of bis(pinacolato)diboron, 0.7 g (0.001 mol) of DPPF palladium dichloride, 19.6 g (0.2 mol) of potassium acetate, and 300 mL of DMF were added. The reaction was carried out at 90 °C for 10 hours under nitrogen protection. After the reaction was completed, the organic phase was separated, extracted, dried, purified by column chromatography, and the solvent was concentrated to dryness to obtain 26.6 g of a solid with a yield of 83%.

[0103] 6. Synthesis of Compound I-87-6: In a 1 L three-necked flask equipped with mechanical stirring, 32 g (0.1 mol) of I-87-5, 15.8 g (0.1 mol) of 2-bromopyridine, 19.6 g (0.2 mol) of potassium acetate, 0.7 g (0.001 mol) of DPPF palladium dichloride, 400 mL of tetrahydrofuran, and 100 mL of water were added. The temperature was raised to reflux for 12 hours, cooled to room temperature, water was added, and the mixture was extracted with ethyl acetate. The separated organic layer was washed with brine, and the organic phase was separated, extracted, dried, purified by column chromatography, and the solvent was concentrated to dryness to obtain 20.9 g of a solid with a yield of 77%.

[0104] 7. Synthesis of Compound I-87: In a 500 mL three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a nitrogen protection device, I-87-3 (7.56 g, 0.01 mol) and I-87-6 (2.71 g, 0.01 mol) were added successively. Then, 200 mL of ethanol was added, and the mixture was heated under reflux for 24 hours. The reactants were cooled to room temperature, and the resulting yellow solid was filtered. The solid was dissolved in dichloromethane and separated by column chromatography to obtain 4.7 g of a bright yellow solid with a yield of 56%.

[0105] Product MS (m / e): 813; Elemental analysis (C 42 H 14 D 15 IrN4O): Theoretical values: C, 62.05; H, 5.45; Ir, 23.64; N, 6.89; O, 1.97; Measured values: C, 62.16; H, 5.39; N, 7.14.

[0106] Referring to the synthesis method of the above Compound I-87 and the synthesis method disclosed in Patent Application CN14773399A, Compound I-99 was synthesized.

[0107]

[0108] Device Example

[0109] The above-prepared compound was used to prepare an organic electroluminescent device.

[0110] The preparation steps of Device Example 1-1 were as follows: First, an indium tin oxide (ITO) glass substrate with a thickness of 100 nm was cleaned, and then treated with UV ozone and oxygen plasma. After treatment, the substrate was dried in a glove box filled with nitrogen to remove moisture, and then the substrate was mounted on a substrate holder and loaded into a vacuum chamber. The following organic layers were deposited on the ITO anode by thermal vacuum once at a rate of - 7 under a condition of about 5×10 torr as follows:

[0111] Compound HT-1 and Compound HI were co-deposited as a hole injection layer (HIL) with a total thickness of Compound HI accounted for 3% of the total weight of the hole injection layer; Compound HT-1 was used as a hole transport layer (HTL) with a thickness of

[0112] Compound HT-2 was used as an electron blocking layer (EBL) with a thickness of Then, Compound I-87 is doped and co-deposited with the first host compound P-86 and the second host compound N-7 to be used as the emitting layer (EML), with a total thickness of The weight ratio of the first host compound P-86 to the second host compound N-7 is 1:1, and the dopant compound I-87 accounts for 4% of the total weight of the emitting layer; Compound ET-1 is used as the hole blocking layer (HBL), with a thickness of On the HBL, Compound ET-2 and lithium 8-hydroxyquinolate (Liq) are co-deposited as the electron transport layer (ETL), where Liq accounts for 50% of the total weight of the ETL layer, and the total thickness of the ETL layer is Finally, Liq with a thickness of

[0113] is evaporated as the electron injection layer (EIL), and 150 nm of aluminum is evaporated as the cathode. Then, the device is transferred back to the glove box and encapsulated with a glass cover plate to complete the device.

[0114] Device Comparative Examples 1-1 to 1-3: The preparation method is the same as that of Device Example 1-1, except that the host materials of the emitting layer in Comparative Examples 1-1 to 1-3 in Table 1 are used, and the weight ratio of the host material to the dopant is adjusted to 92:8. This is the optimal weight ratio of the host material to the dopant when using a single-component host material, and the device performance is the best at this time.

[0115] Device Comparative Examples 1-4 to 1-6: The preparation method is the same as that of Device Example 1-1, except that the host materials of the emitting layer in Comparative Examples 1-4 to 1-6 in Table 1 are used.

[0116] The detailed device layer partial structures and thicknesses of the device examples and comparative examples provided above are shown in Table 1. For the layers with more than one material used, they are obtained by doping different compounds in the recorded weight ratios.

[0117] Table 1

[0118]

[0119]

[0120] Partial material structures used in the device examples and comparative examples provided above are as shown below:

[0121]

[0122] The performance of the devices in the above embodiments and comparative examples was detected. Table 2 lists the test results of Device Example 1-1 and Device Comparative Examples 1-1 to 1-6. The voltage, external quantum efficiency, color coordinates, peak wavelength, and full width at half maximum in Table 2 were measured at a current density of 20 mA / cm 2 and the lifetime is the time required for the initial luminous brightness of 20000 nit to decay to 95% of the initial brightness.

[0123] Table 2 Device performance detection data

[0124]

[0125]

[0126] Table 2 shows the performance test results of organic electroluminescent devices including different host materials and doped material I-87 light-emitting layers.

[0127] As can be seen from Table 2, the color coordinates of Device Example 1-1 are (0.34, 0.62), the peak wavelength is 525 nm, the full width at half maximum is 60.6 nm, and 20 mA / cm 2The voltage under [specific conditions] is 3.64 V, the external quantum efficiency is 21.31%, the current efficiency is 81 cd / A, and the T95 lifetime is 809 h at 20000 nit. All the performance parameters of device Comparative Example 1-1 are inferior to those of device Example 1-1. The spectrum shows a red shift, especially the T95 lifetime is only 68 h, far less than the lifetime of device Example 1-1. Although the full width at half maximum of device Comparative Example 1-2 is only 58.7 nm, slightly narrower than that of device Example 1-1, and the voltage is close to that of device Example 1-1, its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of device Example 1-1, especially the T95 lifetime is significantly lower than that of device Example 1-1. Although the voltage of Comparative Example 1-3 is only 3.68 V, its spectrum shows a red shift compared with that of device Example 1-1, and its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of device Example 1-1. The peak wavelength and full width at half maximum of device Comparative Example 1-4 are close to those of device Example 1-1, but the voltage is as high as 4.71 V, more than 1 V higher than the voltage of device Example 1-1, and its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of device Example 1-1. The spectrum of device Comparative Example 1-5 shows a slightly red shift compared with that of device Example 1-1, the full width at half maximum is slightly narrower, being 58.6 nm, and these three parameters of voltage, external quantum efficiency, and current efficiency are all inferior to those of device Example 1-1, especially the lifetime is also significantly lower than that of device Example 1-1, with a difference of 181 h. The voltage, external quantum efficiency, current efficiency, and lifetime of device Comparative Example 1-6 are all inferior to those of device Example 1-1. The above results show that using the combination of luminescent layer materials disclosed in the present invention can improve the spectrum and significantly enhance the comprehensive performance of the device, especially achieving unexpected effects in aspects such as reducing voltage, improving efficiency, and extending lifetime.

[0128] The preparation steps of device Example 2-1 are the same as those of device Example 1-1, except that the doping material compound used in the luminescent layer is dopant compound I-99, which accounts for 6% of the total weight of the luminescent layer.

[0129] Comparative Examples 2-1 to 2-3: The preparation method is the same as that of device Example 2-1, except that only the host materials of the luminescent layer in Comparative Examples 2-1 to 2-3 in Table 3 are used, and the weight ratio of the host material to the dopant is adjusted to 90:10. This is the optimal weight ratio of the host material to the dopant when using a single-component host material, and the device performance is the best at this time.

[0130] Comparative Examples 2-4 to 2-6: The preparation method is the same as that of device Example 2-1, except that only the host materials of the luminescent layer in Comparative Examples 2-4 to 2-6 in Table 3 are used.

[0131] The detailed device layer partial structures and thicknesses of the device examples and comparative examples provided above are shown in Table 3. For layers with more than one material used, different compounds are doped in the recorded weight ratios.

[0132] Table 3

[0133]

[0134]

[0135] The structures of compounds HI, HT-1, HT-2, GH-1, GH-2, GH-3, ET-1, and ET-2 used in the device in Table 3 are the same as those in Table 1.

[0136] Table 4 lists the test results of device example 2-1 and device comparative examples 2-1 to 2-6. In Table 4, the voltage, external quantum efficiency, color coordinates, peak wavelength, and full width at half maximum are measured at a current density of 20 mA / cm 2 and the lifetime is the time required for the initial emission luminance of 20000 nit to decay to 95% of the initial luminance.

[0137] Table 4 Device performance detection data

[0138]

[0139] Table 4 shows the performance test results of organic electroluminescent devices including an emission layer with different host materials and doping material I-99.

[0140] As can be seen from Table 4, the color coordinates of device example 2-1 are (0.31, 0.65), the peak wavelength is 523 nm, the full width at half maximum is 61.8 nm, and at 20 mA / cm 2The voltage under [conditions] is 3.76 V, the external quantum efficiency is as high as 21.79%, the current efficiency is 77 cd / A, and the T95 life at 20,000 nits is 776 h. The spectrum of device Comparative Example 2-1 has a slight red shift, and the full width at half maximum is close to that of device Example 2-1, but the voltage is as high as 4.82 V, more than 1 V higher than that of Example 2-1. At the same time, the external quantum efficiency, current efficiency, and T95 life are all inferior to those of device Example 2-1. The spectrum of device Comparative Example 2-2 has a red shift and the full width at half maximum is slightly narrower, but the voltage is 3.97 V, 0.21 V higher than that of device Example 2-1, and the external quantum efficiency, current efficiency, and T95 life are all inferior to those of device Example 2-1. The color coordinates of device Comparative Example 2-3 are (0.34, 0.62), and the spectrum has an obvious red shift compared with device Example 2-1. Although the voltage is close to that of Example 2-1, the external quantum efficiency, current efficiency, and T95 life are all inferior to those of device Example 2-1. The spectrum of device Comparative Example 2-4 has a slight red shift, and other parameters are all inferior to those of device Example 2-1. In particular, the voltage is as high as 4.84 V, more than 1.0 V higher than that of device Example 2-1. The spectrum of device Comparative Example 2-5 has a slight red shift, the full width at half maximum is slightly narrower, the external quantum efficiency is 21.27%, the current efficiency is 72 cd / A, lower than that of device Example 2-1, and the T95 life is 559 h, 217 h less than that of device Example 2-1. The voltage, spectrum, full width at half maximum, external quantum efficiency, and current efficiency of device Comparative Example 2-6 are similar to those of device Example 2-1, but the T95 life is 734 h, 42 h less than that of device Example 2-1.

[0141] The above results show that using the combination of luminescent layer materials of the present invention can effectively improve the voltage of the electroluminescent device, and improve the device efficiency and life. The electroluminescent device containing the combination of the host material and the doping material provided by the present invention has more excellent comprehensive performance.

[0142] In summary, the organic electroluminescent device disclosed in the present invention includes at least one luminescent layer, and the luminescent layer includes two host compounds with specific structures and a phosphorescent dopant compound, wherein at least the first host compound includes a carbazole-carbazole structure, and the second host compound includes a structure of general formula (Ⅱ). For the specific phosphorescent dopant included in the material combination, compared with using a conventional host material combination or a single host material, using the specific host material combination of the present invention can significantly improve the comprehensive performance of the organic electroluminescent device, such as voltage, luminous efficiency, spectrum, and life.

[0143] It should be understood that the various embodiments described herein are merely examples and are not intended to limit the scope of the present invention. Thus, as will be apparent to those skilled in the art, the claimed invention may include variations of the specific and preferred embodiments described herein. Many of the materials and structures described herein may be replaced with other materials and structures without departing from the spirit of the present invention. It should be understood that the various theories as to why the present invention works are not intended to be limiting.

Claims

1. A phosphorescent organic electroluminescent material, characterized in that, Comprising: A host material and a doping material, wherein the host material comprises a first host compound and a second host compound; The first host compound is selected from the following compounds: The second main compound is selected from the compounds having the structures shown below: The doping material is selected from the following compounds:

2. The phosphorescent organic electroluminescent material according to claim 1, wherein The mixing mass ratio of the host material and the doping material is (80-99):(1-20).

3. The phosphorescent organic electroluminescent material according to claim 1, wherein The mixing mass ratio of the host material and the doping material is (90-99):(1-10).

4. The phosphorescent organic electroluminescent material according to claim 1, wherein The mixing mass ratio of the first host compound and the second host compound in the host material is (0.8-1.2):(0.8-1.2).

5. The phosphorescent organic electroluminescent material according to claim 1, wherein The mixing mass ratio of the first host compound and the second host compound in the host material is 1:

1.

6. Application of the phosphorescent organic electroluminescent material according to any one of claims 1-5 in an electroluminescent device.

7. Application of the phosphorescent organic electroluminescent material according to any one of claims 1-5 in an organic layer of an electroluminescent device.

8. Application of the phosphorescent organic electroluminescent material according to any one of claims 1-5 in a light-emitting layer of an electroluminescent device.

9. The application according to claim 8, wherein Calculated based on the total mass of the light-emitting layer material, the mass of the first host compound accounts for 40%-50%, the mass of the second host compound accounts for 40%-50%, and the mass of the doping material accounts for 1%-10%.

10. The application according to claim 8, wherein, Calculated based on the total mass of the light-emitting layer material, the mass of the first host compound accounts for 47%-48%, the mass of the second host compound accounts for 47%-48%, and the mass of the doping material accounts for 4%-6%.

11. An electroluminescent device comprising the phosphorescent organic electroluminescent material according to any one of claims 1-5.

12. The electroluminescent device according to claim 11, wherein Comprising an anode, a cathode, and at least one light-emitting layer disposed between the anode and the cathode, wherein the light-emitting layer comprises the phosphorescent organic electroluminescent material according to any one of claims 1-5.

13. The electroluminescent device according to claim 12, characterized in that, A hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are disposed between the anode and the cathode, and the light-emitting layer comprises the phosphorescent organic electroluminescent material according to any one of claims 1-5.

14. The electroluminescent device according to claim 13, wherein, A packaging layer is further disposed on the cathode.

15. A display component, characterized in that, Comprising the electroluminescent device according to any one of claims 11-14.

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