CN110407858B

CN110407858B - Novel compound, application thereof and organic electroluminescent device using compound

Info

Publication number: CN110407858B
Application number: CN201910649982.XA
Authority: CN
Inventors: 段炼; 张跃威; 张东东
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2019-07-18
Filing date: 2019-07-18
Publication date: 2020-07-14
Anticipated expiration: 2039-07-18
Also published as: CN110407858A

Abstract

The invention relates to a novel organic compound, application thereof and an organic electroluminescent device adopting the compound, wherein the compound has the following structure:

wherein Y is¹、Y²And Y³Each independently selected from H or B, and at most one of which is H; x¹、X²And X³Each independently selected from N or H, and at most one of which is H; x⁴、X⁵And X⁶Each independently selected from H, a single bond, O, S, or CR; r¹～R¹⁸Each independently selected from hydrogen, deuterium, or one of the following substituted or unsubstituted groups: C1-C36 alkyl, C6-C48 monocyclic aromatic hydrocarbon or polycyclic aromatic hydrocarbon, C3-C48 monocyclic heteroaromatic hydrocarbon or polycyclic heteroaromatic hydrocarbon, and R¹～R¹⁸Two adjacent groups in the compound can be bonded with each other to form C1-C10 cycloparaffin, C6-C30 arene or C5-C30 heteroarene.

Description

Novel compound, application thereof and organic electroluminescent device using compound

Technical Field

The invention relates to a novel compound, application of the compound and an organic light-emitting device adopting the compound.

Background

The Organic electroluminescent device (O L ED: Organic L light Emission Diodes) is a device with a sandwich-like structure, comprising positive and negative electrode film layers and an Organic functional material layer sandwiched between the electrode film layers, because the O L ED device has the advantages of high brightness, fast response, wide viewing angle, simple process, flexibility and the like, the O L ED device is concerned about in the novel display technical field and the novel illumination technical field.

With the continuous advancement of O L ED in two fields of lighting and display, people pay more attention to the research on the core materials of O L ED devices, because an O L ED device with good efficiency and long service life is generally the result of optimizing and matching of device structures and various organic materials, in order to prepare an O L ED light-emitting device with lower driving voltage, better light-emitting efficiency and longer service life, the continuous improvement of the performance of an O L ED device is realized, and not only the structure and the manufacturing process of an O L ED device need to be innovated, but also the continuous research and innovation on photoelectric functional materials in an O L ED device are needed to prepare functional materials with higher performance.

In terms of selection of O L ED materials, singlet-state luminescent fluorescent materials are good in service life, low in price and low in efficiency, triplet-state luminescent phosphorescent materials are high in efficiency and expensive in price, and the problem of service life of blue-light materials is not solved all the time, Adachi of Kyushu university of Japan proposes a new class of organic luminescent materials, namely Thermal Activation Delayed Fluorescence (TADF) materials, wherein singlet-triplet energy gaps (delta EST) of the materials are very small (<0.3eV), triplet excitons can be converted into singlet excitons to emit light through reverse intersystem crossing (RIST), and therefore the internal quantum efficiency of the device can reach 100%.

In the prior art, a new structural compound design is performed by adopting a multiple resonance induced thermal activation delayed fluorescence (MR-TADF) strategy, for example, patent applications CN107851724, CN108431984 and the like design a polycyclic aromatic compound formed by connecting a plurality of aromatic rings by a single boron atom and a nitrogen atom, i.e., a special rigid molecular system (as shown in the following formula (a)) containing a boron (B) atom and a nitrogen (N) atom is constructed, wherein Y is¹Is B, X¹And X²The thermally activated delayed fluorescence molecules are respectively and independently N-R, although the thermally activated delayed fluorescence molecules can have high radiative transition rate and high color purity, the larger HOMO-L UMO overlap, so that the single-triplet state energy extreme difference (delta Est) of the material is larger, and the serious device effect is generatedThe rate of roll-off.

Disclosure of Invention

In order to solve the technical problem, the invention provides a novel thermal activation delayed fluorescent material which can be applied to the field of organic electroluminescence.

The organic compound of the present invention is represented by the following general formula (1):

in the formula (1), Y¹、Y²And Y³Each independently selected from H or B, and at most one of which is H;

X¹、X²and X³Each independently selected from N or H, and at most one of which is H;

X⁴、X⁵and X⁶Each independently selected from H, a single bond, O, S or CR, wherein R is selected from one of the following substituted or unsubstituted groups: C1-C10 alkyl, C6-C30 monocyclic aromatic hydrocarbon or polycyclic aromatic hydrocarbon, C5-C30 monocyclic heteroaromatic hydrocarbon or polycyclic heteroaromatic hydrocarbon;

R¹～R¹⁸each independently selected from hydrogen, deuterium, or one of the following substituted or unsubstituted groups: C1-C36 alkyl, C6-C48 monocyclic aromatic hydrocarbon or polycyclic aromatic hydrocarbon, C3-C48 monocyclic heteroaromatic hydrocarbon or polycyclic heteroaromatic hydrocarbon, and R¹～R¹⁸Two adjacent groups in (a) may be bonded to each other to form a C1-C10 cycloalkane, a C6-C30 arene or a C5-C30 heteroarene;

when the substituent exists in the groups, the substituent groups are respectively and independently selected from deuterium, alkyl or cycloalkyl of C1-C10, aryl of C6-C30 and heteroaryl of C3-C30.

Further, the compound of the above general formula (1) is preferably represented by the following general formulae (2-1) to (2-2):

in formulae (2-1) and (2-2): r¹～R²¹Each independently selected from hydrogen, deuterium or one of the following substituted or unsubstituted groups: C1-C36 alkyl, C6-C48 monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon, C3-C48 monocyclic heteroaromatic hydrocarbon or condensed ring heteroaromatic hydrocarbon, when the above groups have substituents, the substituents are respectively and independently selected from deuterium, C1-C10 alkyl or cycloalkyl, C6-C30 aryl and C3-C30 heteroaryl.

Further, R mentioned above¹～R²¹Each independently selected from the following substituents: hydrogen, deuterium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2, 2-trifluoroethyl, phenyl, naphthyl, anthracenyl, benzanthryl, phenanthryl, benzophenanthryl, pyrenyl, bornyl, perylenyl, fluorescent anthracenyl, tetracenyl, pentacenyl, benzopyrenyl, biphenyl, idophenyl, terphenyl, quaterphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis-or trans-indenofluorenyl, trimeric indenyl, isotridecyl, spirotrimeric indenyl, spiroisotridecyl, furyl, benzofuranyl, spirodicloro-yl, phenyl, terphenyl, phenanthryl, and phenanthryl, Isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, pyridyl, quinolinyl, isoquinolinyl, acridinyl, phenanthridinyl, benzo-5, 6-quinolinyl, benzo-6, 7-quinolinyl, benzo-7, 8-quinolinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthoimidazolyl, phenanthroimidazolyl, pyridoimidazolyl, pyrazinoimidazolyl, quinoxalimidazolyl, oxazolyl, benzoxazolyl, naphthooxazolyl, anthraoxazolyl, phenanthroxazolyl, 1, 2-thiazolyl, 1, 3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyrazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazanthryl, 2, 7-diazpyrenyl, 2, 3-diazpyrenyl, 1, 6-diazpyrenyl, 1, 8-diazpyrenyl, 4, 5-diazenyl, 4,5,9, 10-tetraazaperyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbazinyl, phenanthrolinyl, 1,2, 3-triazolyl, 1,2, 4-triazolyl, benzotriazolyl, 1,2, 3-oxadiazolyl, 1,2, 4-oxadiazolyl, 1,2, 5-oxadiazolyl, 1,2, 3-thiadiazolyl, 1,2, 4-thiadiazolyl, 1,2, 5-thiadiazolyl, 1,3, 4-thiadiazolyl, 1,3, 5-triazinyl, 1,2, 4-triazinyl, 1,2, 3-triazinyl, tetrazolyl, 1,2,4, 5-tetrazinyl, 1,2,3, 4-tetrazinyl, 1,2,3, 5-tetrazinyl, purinyl, pteridinyl, indolizinyl, benzothiadiazolyl, 9-dimethylazinyl, (poly) halobenzene, (poly) cyanobenzene, (poly) trifluoromethylbenzene, and the like, or a combination selected from the two groups.

Further, the compounds represented by the general formula (1) of the present invention may preferably be compounds C-1 to C-123 of the following specific structures, which are merely representative:

the general formula of the invention also provides an organic electroluminescent device, which comprises a substrate, a first electrode, a second electrode and one or more organic layers which are inserted between the first electrode and the second electrode, wherein the organic layers comprise the compound shown in any one of the general formula (1), the formula (2-1) and the formula (2-2).

Specifically, one embodiment of the present invention provides an organic electroluminescent device including a substrate, and an anode layer, a plurality of light emitting functional layers, and a cathode layer sequentially formed on the substrate; the light-emitting functional layer comprises a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer, wherein the hole injection layer is formed on the anode layer, the hole transport layer is formed on the hole injection layer, the cathode layer is formed on the electron transport layer, and the light-emitting layer is arranged between the hole transport layer and the electron transport layer; wherein the light-emitting layer contains a compound represented by the general formula (1), a compound represented by the general formula (2-1) or a compound represented by the general formula (2-2).

The O L ED device prepared by the compound has low starting voltage, high luminous efficiency and better service life.

The specific reason why the above-mentioned compound of the present invention is excellent in performance when used in an organic electroluminescent device is not clear, and the following reason is presumed to be possible:

rigid carbazole, phenoxazine or phenothiazine derivative donors are respectively introduced into positions 1,3 and 5 of a central benzene ring of the novel general formula compound, so that the increase of molecular rigidity is favorable for further reducing vibration relaxation of the compound and enabling a spectrum to be blue-shifted. Meanwhile, a plurality of boron atoms, namely not less than two boron atoms, are introduced into the

positions

2,4 and 6 of the benzene ring, so that the electron-withdrawing capability of the molecule is increased to a certain extent, and a carbazole derivative donor retaining ring adjacent to the molecule is formed, thereby ensuring that the target MR-TADF molecule can realize smaller delta Est while maintaining high radiation transition rate and high color purity.

The compound can be used as a luminescent layer material in an organic electroluminescent device and can also be used as a fluorescent sensitizer in the organic electroluminescent device.

In addition, the preparation process of the compound is simple and feasible, the raw materials are easy to obtain, and the compound is suitable for mass production and amplification.

Drawings

FIG. 1: the structure of the organic electroluminescent device prepared by the invention is shown in the figure, wherein 1 is a substrate, 2 is an anode, 3 is a hole transport layer, 4 is an organic luminescent layer, 5 is an electron transport layer, and 6 is a cathode.

Detailed Description

The specific production method of the above-mentioned novel compound of the present invention will be described in detail below by taking a plurality of synthesis examples as examples, but the production method of the present invention is not limited to these synthesis examples.

Basic chemical raw materials of various chemicals used in the present invention, such as petroleum ether, tert-butylbenzene, ethyl acetate, sodium sulfate, toluene, dichloromethane, potassium carbonate, boron tribromide, N-diisopropylethylamine, reaction intermediate, and the like, are commercially available from shanghai tatarian technologies ltd and silong chemical ltd. The mass spectrometer used for determining the following compounds was a ZAB-HS type mass spectrometer measurement (manufactured by Micromass, UK).

Next, the method for synthesizing the compound of the present invention will be briefly described (scheme (1)), and first, X is synthesized using n-butyllithium, t-butyllithium or the like¹、X²And X³The hydrogen atoms in between undergo ortho-metallation. Then, after metal exchange of lithium-boron or lithium-phosphorus is performed by adding boron tribromide, phosphorus trichloride, or the like, a bronsted base (Bronstedbase) such as N, N-diisopropylethylamine is added to perform a Tandem boron-doped Friedel-crafts reaction (Tandem Bora-Friedel-crafts reaction), and the target compound can be obtained.

More specifically, the following gives a synthetic method of a representative specific compound of the present invention.

Synthetic examples

Synthesis example 1:

synthesis of Compound C-9

Under nitrogen atmosphere, adding a pentane solution (18.96M L, 1.60M, 30.34mmol) of tert-butyl lithium slowly into a solution of a Br generation precursor (13.62g, 13.79mmol) of tert-butylbenzene (150M L) at 0 ℃, then heating to 80 ℃, 100 ℃, 120 ℃ in sequence, reacting for 1 hour, cooling to-30 ℃ after the reaction is finished, slowly adding boron tribromide (7.6g, 30.34mmol), stirring for 0.5 hour continuously at room temperature, adding N, N-diisopropylethylamine (5.35g, 41.37mmol) at room temperature, continuing to react for 5 hours at 145 ℃, vacuum drying the solvent, passing through a silica gel column (developing agent: ethyl acetate: petroleum ether: 50:1), obtaining a target compound C-9(1.00g, 8% yield, HP L C analytical purity 99.56%), which is a yellow solid, MA L DI-MS result: TOF peak 926.45 elemental analysis result: C63%, theoretical value: 7.7: 3: 867: 7: 3.7: 3: 7: 863: 7: 3: 863: 3: 7: 3% of N.

Synthesis example 2:

synthesis of Compound C-1

This example is substantially the same as Synthesis example 1 except that in this example, C-9-1 was replaced with C-1-1 of the same amount as the target compound C-9(0.81g, 10% yield, HP L C analytical purity 99.66%) as a yellow solid, and MA L DI-TOF-MS showed molecular ion peaks of 589.76 as elemental analyses of theoretical values of C85.61%, H3.59%, B3.67%, N7.13%, experimental values of C85.12%, H4.01B 3.58, and N7.29%.

Synthesis example 3

Synthesis of Compound C-2

This example is substantially the same as Synthesis example 1 except that in this example, C-9-1 was replaced with C-2-1 of the same amount as the target compound C-9(1.02g, 11% yield, HP L C analytical purity 99.55%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 673.89 as elemental analyses, theoretical values of C85.61%, H4.94%, B3.21%, N6.24%, experimental values of C85.12%, H4.46%, B3.68%, and N6.74%.

Synthesis example 4

Synthesis of Compound C-4

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-4-1 of the same amount as that of the target compound C-4(1.42g, 10% yield, HP L C analytical purity 99.35%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 757.89 elemental analysis showed theoretical values of C, 85.61%, H, 5.99%, B, 2.85%, N, 5.55%, experimental values of C, 85.41%, H, 5.89%, B, 2.95%, and N, 5.75%.

Synthesis example 5

Synthesis of Compound C-17

This example is substantially the same as synthetic example 1 except that in this example, C-26-1 was replaced with C-17-1 in an equivalent amount, the target compound C-17(1.44g, 10% yield, HP L C analytical purity 99.26%) was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks were 1045.29, the elemental analyses showed theoretical values of C89.58%, H4.34%, B2.07%, N4.02%, experimental values of C89.88%, H4.16%, B2.18%, and N3.78%.

Synthetic example 6:

synthesis of Compound C-30

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-30-1 in an equivalent amount, the target compound C-30(1.29g, 10% yield, HP L C analytical purity 99.36%) was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks were 923.31, the theoretical values of C, 85.82%, H, 4.26%, B, 2.34%, N, 7.58%, the experimental values of C, 85.83%, H, 4.25%, B, 2.24%, and N, 7.68%.

Synthetic example 7:

synthesis of Compound C-34

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-34-1, the objective compound C-34(1.27g, 10% yield, HP L C analytical purity 99.36%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 919.31 as elemental analyses, theoretical values of C86.20%, H3.84%, B2.35%, N7.62%, experimental values of C85.92%, H4.16%, B2.53%, and N7.39%.

Synthesis example 8:

synthesis of Compound C-100

This example is substantially the same as synthetic example 1, except that in this example, C-9-1 was replaced with C-100-1 in an amount equivalent to that of the target compound C-100(0.83g, 10% yield, HP L C analytical purity 99.55%) as a yellow solid, and MA L DI-TOF-MS showed molecular ion peaks of 603.62 elemental analysis showed theoretical values of C85.61%, H3.84%, B3.58%, N6.97%, experimental values of C85.34%, H3.57%, B3.78%, and N7.31%.

Synthetic example 9:

synthesis of Compound C-97

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-97-1 in an equivalent amount, the target compound C-97(0.92g, 10% yield, HP L C analytical purity 99.55%) was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks were 665.62, which was theoretical values of C86.65%, H3.79%, B3.25%, N6.32%, and experimental values of C86.85%, H3.59%, B3.05%, and N6.52%.

Synthetic example 10:

synthesis of Compound C-98

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-98-1 in an equivalent amount, the target compound C-98(0.62g, 6% yield, HP L C analytical purity 99.75%) was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks were 748.11, the theoretical values of C86.63%, H4.44%, B1.44%, N7.48%, the experimental values of C86.54%, H4.57B 1.78, and N7.11%.

Synthetic example 11:

synthesis of Compound C-99

This example is substantially the same as Synthesis example 1 except that in this example, C-9-1 was replaced with C-99-1 in an amount equivalent to that of the target compound C-99(0.62g, 6% yield, HP L C analytical purity 99.75%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 746.58 as elemental analyses, theoretical values of C86.86%, H4.18%, B1.45%, N7.50%, experimental values of C86.34%, H4.57B 1.78, and N7.31%.

Synthetic example 12:

synthesis of Compound C-109

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-109-1, which is an equivalent amount of C-109-1, the target compound C-109(0.90g, 10% yield, HP L C analytical purity 99.55%) and was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 655.48 elemental analysis results, which were theoretical values of C, 76.97%, H, 3.54%, B, 3.30%, N, 6.41%, S, 9.78%, experimental values of C, 76.77%, H, 3.74%, B, 3.50%, N, 6.31%, and S, 9.68%.

Synthetic example 13:

synthesis of Compound C-113

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-113-1, the objective compound C-109(0.90g, 11% yield, HP L C analytical purity 99.55%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 621.44 elemental analyses showed theoretical values of C, 81.20%, H, 3.41%, B, 3.48%, N, 6.76%, O, 5.15%, experimental values of C, 81.10%, H, 3.51%, B, 3.48%, N, 6.66%, and O, 5.25%.

Synthesis example 14:

synthesis of Compound C-115

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-115-1, the objective compound C-115(1.05g, 12% yield, HP L C analytical purity 99.55%) and a yellow solid were obtained, and MA L DI-TOF-MS showed that the molecular ion peaks showed 637.58 elemental analysis results, theoretical values of C, 79.16%, H, 3.32%, B, 3.39%, N, 6.59%, O, 7.53%, experimental values of C, 79.36%, H, 3.12%, B, 3.29%, N, 6.69%, and O, 7.53%.

Synthetic example 15:

synthesis of Compound C-121

This example is substantially the same as synthetic example 1 except that in this example, C-9-1 was replaced with C-121-1 of the same amount as that of the target compound C-121(1.15g, 12% yield, HP L C analytical purity 99.35%) as a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peak was 699.28, the theoretical values of C, 73.84%, H, 3.31%, B, 3.09%, N, 6.01%, S, 13.75%, the experimental values of C, 73.64%, H, 3.51%, B, 3.39%, N, 6.01%, and S, 13.45%.

Synthetic example 16:

synthesis of Compound C-136

Under nitrogen atmosphere, a pentane solution of tert-butyl lithium (31.03M L, 1.60M, 49.64mmol) was slowly added to a 0 ℃ solution of C-55-1(9.0g, 13.79mmol) of tert-butylbenzene (150M L), then the temperature was sequentially raised to 80 ℃, 100 ℃, and 120 ℃ for 1 hour, after the reaction was completed, the temperature was lowered to-30 ℃, boron tribromide (12.43g, 49.64mmol) was slowly added, stirring was continued for 0.5 hour at room temperature, N-diisopropylethylamine (8.99g, 41.37mmol) was added at room temperature, and after the reaction was continued for 5 hours at 145 ℃, the solvent was vacuum-dried, and a silica gel column was passed through (developing agent: ethyl acetate: petroleum ether: 50:1) to obtain the target compound C-55(0.60g, 7.3% yield, HP L C analytical purity 99.56%), which was yellow solid, MA L DI-MS as a result, TOF peak of molecular ion: 2, elemental analysis result: 389: 3.3: 3% of element, experimental N: 83: 3.83%, and experimental N-2: 3: 3.6: 3: 3..

Synthetic example 17:

synthesis of Compound C-136

This example is substantially the same as Synthesis example 16 except that in this example, C-55-1 was replaced with C-56-1 in an equivalent amount, the target compound C-121(1.15g, 12% yield, HP L C analytical purity 99.35%) was a yellow solid, and MA L DI-TOF-MS showed that the molecular ion peaks showed 699.28 elemental analyses showed theoretical values of C, 84.54%, H, 3.55%, B, 5.19%, N, 6.72%, and experimental values of C, 84.44%, H, 3.65%, B, 5.09%, and N, 6.82%.

The technical effects and advantages of the invention are shown and verified by testing practical use performance by specifically applying the compound of the invention to an organic electroluminescent device.

The organic electroluminescent device includes a first electrode, a second electrode, and an organic material layer between the two electrodes. The organic material may be divided into a plurality of regions, for example, the organic material layer may include a hole transport region, a light emitting layer, and an electron transport region.

The anode may be made of transparent conductive oxide materials such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), and any combinations thereof, and the cathode may be made of metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-L i), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag), and any combinations thereof.

The hole transport region may be a single-layer structure of a hole transport layer (HT L) including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing a plurality of compounds, or a multi-layer structure including at least one of a hole injection layer (HI L), a hole transport layer (HT L), and an electron blocking layer (EB L).

The material of the hole transport region may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylenevinylene, polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphorsulfonic acid (Pani/CSA), polyaniline/poly (4-styrenesulfonate) (Pani/PSS), aromatic amine derivatives, and the like.

The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit different wavelength spectra, and may also include a Host material (Host). The light emitting layer may be a single color light emitting layer emitting a single color of red, green, blue, or the like. The single color light emitting layers of a plurality of different colors may be arranged in a planar manner in accordance with a pixel pattern, or may be stacked to form a color light emitting layer. When the light emitting layers of different colors are stacked together, they may be spaced apart from each other or may be connected to each other. The light-emitting layer may be a single color light-emitting layer capable of emitting red, green, blue, or the like at the same time.

The electron transport region may also be a multilayer structure including at least one of an electron injection layer (EI L), an electron transport layer (ET L), and a hole blocking layer (HB L).

The preparation process of the organic electroluminescent device is described as follows with reference to the attached figure 1: an anode 2, a hole transport layer 3, an organic light emitting layer 4, an electron transport layer 5, and a cathode 6 are sequentially deposited on a substrate 1, and then encapsulated. In the preparation of the organic light-emitting layer 4, the organic light-emitting layer 4 is formed by a co-deposition method using a wide band gap material source, an electron donor material source, an electron acceptor material source, and a resonance TADF material source.

Specifically, the preparation method of the organic electroluminescent device comprises the following steps:

1. the anode material coated glass plate was sonicated in a commercial detergent, rinsed in deionized water, washed in acetone: ultrasonically removing oil in an ethanol mixed solvent, baking in a clean environment until the water is completely removed, cleaning by using ultraviolet light and ozone, and bombarding the surface by using low-energy cationic beams;

2. placing the glass plate with the anode in a vacuum chamber, and vacuumizing to 1 × 10^-5～9×10^-3Pa, forming a hole injection layer by vacuum evaporation of a hole injection material on the anode layer film, wherein the evaporation rate is 0.1-0.5 nm/s;

3. vacuum evaporating hole transport material on the hole injection layer to form a hole transport layer with an evaporation rate of 0.1-0.5nm/s,

4. an organic light-emitting layer of the device is vacuum evaporated on the hole transport layer, the organic light-emitting layer material comprises a main body material and TADF dye, and the evaporation rate of the main body material, the evaporation speed of the sensitizer material and the evaporation rate of the dye are adjusted by a multi-source co-evaporation method to enable the dye to reach a preset doping proportion;

5. forming an electron transport layer on the organic light-emitting layer by vacuum evaporation of an electron transport material of the device, wherein the evaporation rate is 0.1-0.5 nm/s;

6. l iF is vacuum evaporated on the electron transport layer at 0.1-0.5nm/s to be used as an electron injection layer, and an Al layer is vacuum evaporated at 0.5-1nm/s to be used as a cathode of the device.

The display device can be specifically a display device such as an O L ED display, and any product or component with a display function such as a television, a digital camera, a mobile phone, a tablet computer and the like which comprises the display device.

The organic electroluminescent device according to the invention is further illustrated by the following specific examples.

Device example 1

The structure of the organic electroluminescent device prepared in this example is as follows:

ITO/HI(10nm)/HT(40nm)/Host:3wt％C-9(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the anode material is ITO, the hole injection layer material is HI, the total thickness is 5-30nm generally and 10nm in the embodiment, the hole transport layer material is HT, the total thickness is 5-500nm generally and 40nm in the embodiment, Host is a Host material with wide band gap of an organic light emitting layer, C-9 is dye and the doping concentration is 3 wt%, the thickness of the organic light emitting layer is 1-200nm generally and 30nm in the embodiment, the material of the electron transport layer is ET, the thickness is 5-300nm generally and 30nm in the embodiment, and L iF (0.5nm) and aluminum metal (150nm) are selected as the electron injection layer and the cathode material.

A DC voltage was applied to the organic electroluminescent element D1 prepared in this example, and 10cd/m was measured²The characteristics in light emission were such that blue light emission (driving voltage of 3.0V) having a wavelength of 459nm, a half-peak width of 34nm, CIE color coordinates (x, y) (0.14,0.18), and an external quantum efficiency EQE of 28.8% was obtained.

Device example 2

The same preparation method as that of the device example 1 except that the wide band gap type Host material used in the light emitting layer was replaced with the TADF type Host TD, the specific device structure was as follows:

ITO/HI(10nm)/HT(40nm)/TD:3wt％C-67(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D2 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 2.6V) having a wavelength of 460nm, a half-peak width of 30nm, CIE color coordinates (x, y) (0.13,0.18), and an external quantum efficiency EQE of 32.4% was obtained.

Device example 3

The same procedure as in device example 1 was followed except that the dye used in the light-emitting layer was replaced with C-1 instead of C-9. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/Host:3wt％C-1(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D3 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 3.0V) having a wavelength of 451nm, a half-peak width of 31nm, CIE color coordinates (x, y) (0.13,0.16), and an external quantum efficiency EQE of 28.3% was obtained.

Device example 4

The same preparation method as that of device example 1 was used except that the wide band gap type Host material Host in the light-emitting layer was replaced with TADF type Host TD and the dye was replaced with C-67 to C-75. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/TD:3wt％C-75(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D4 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 2.6V) having a wavelength of 452nm, a half-peak width of 30nm, CIE color coordinates (x, y) (0.13,0.15), and external quantum efficiency EQE of 31.4% was obtained.

Device example 5

The same procedure as in device example 1 was followed except that the dye in the light-emitting layer was replaced with C-34 from C-9. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/Host:3wt％C-34(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D5 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (driving voltage of 3.0V) having a wavelength of 465nm, a half-peak width of 34nm, CIE color coordinates (x, y) ═ 0.14,0.19, and an external quantum efficiency EQE of 29.3% was obtained.

Device example 6

The same preparation method as that of device example 1 was used except that the wide band gap type Host material Host in the light-emitting layer was replaced with TADF type Host TD and the dye was replaced with C-67 to C-83. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/TD:3wt％C-83(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D6 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 2.6V) having a wavelength of 464nm, a half-peak width of 32nm, CIE color coordinates (x, y) ═ 0.12,0.18, and an external quantum efficiency EQE of 33.6% was obtained.

Device example 7

The same procedure as in device example 1 was followed except that the dye in the light-emitting layer was replaced with C-109 from C-9. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/Host:3wt％C-109(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D7 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 2.8V) having a wavelength of 469nm, a half-peak width of 31nm, CIE color coordinates (x, y) ═ 0.12,0.20, and an external quantum efficiency EQE of 29.3% was obtained.

Device example 8

The same preparation method as that of device example 1 was used except that the wide band gap type Host material Host in the light-emitting layer was replaced with TADF type Host TD and the dye was replaced with C-9 to C-109. The device structure is as follows:

ITO/HI(10nm)/HT(40nm)/TD:3wt％C-109(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device D8 prepared in this example were as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue emission (driving) having a wavelength of 467nm, a full width at half maximum of 28nm, CIE color coordinates (x, y) (0.12,0.18), and an external quantum efficiency EQE of 32.4% was obtainedThe voltage is 2.4V).

Comparative device example 1

The same preparation method as that of device example 1 was followed except that the compound C-9 of the present invention used in the light-emitting layer was replaced with the compound P1 of the prior art, and the specific device structure was as follows:

ITO/HI(10nm)/HT(40nm)/Host:3wt％P1(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device DD1 prepared in this example are as follows: when a dc voltage was applied and the characteristics were measured at 10cd/m2 light emission, blue light emission (driving voltage of 3.1V) with a wavelength of 464nm, a half-peak width of 30nm, CIE color coordinates (x, y) (0.15,0.10) and an external quantum efficiency EQE of 22.3% was obtained.

Comparative device example 2

The same preparation method as that of device example 2 except that the compound C-67 of the present invention used in the light-emitting layer was replaced with the compound P1 of the prior art, and a specific device structure was as follows:

ITO/HI(10nm)/HT(40nm)/TD:3wt％P1(30nm)/ET(30nm)/LiF(0.5nm)/Al(150nm)

the device performance results of the organic electroluminescent device DD2 prepared in this example are as follows: applying a DC voltage, and measuring 10cd/m²The characteristics in light emission were such that blue light emission (drive voltage of 2.8V) having a wavelength of 464nm, a peak width at half maximum of 28nm, CIE color coordinates (x, y) ═ 0.15,0.09, and external quantum efficiency EQE of 26.9% was obtained.

The structural formulas of the various organic materials used in the above examples are as follows:

specific performance data of the organic electroluminescent devices D1 to D8 and the devices DD1 and DD2 prepared in the above respective device examples are detailed in table 1 below:

table 1:

the experimental data show that after the novel MR-TADF material provided by the invention is prepared and applied to an organic electroluminescent device, the device has high color purity, high luminous efficiency and good performance, and meanwhile, the low-efficiency roll-off of the electroluminescent device is realized, so that the novel compound is an organic luminous functional material with good performance, and is expected to be popularized and commercialized.

Although the invention has been described in connection with the embodiments, the invention is not limited to the embodiments described above, and it should be understood that various modifications and improvements can be made by those skilled in the art within the spirit of the invention, and the scope of the invention is outlined by the appended claims.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. An organic compound represented by the following formulae (2-1) to (2-2):

in formulae (2-1) and (2-2): r¹～R²¹Each independently selected from the following substituents: hydrogen, deuterium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trihexylFluoromethyl, pentafluoroethyl, 2,2, 2-trifluoroethyl, phenyl, naphthyl, anthracenyl, benzanthracenyl, phenanthryl, benzophenanthryl, pyrenyl, celtyl, perylenyl, fluoranthenyl, tetracenyl, pentacenyl, benzopyrenyl, biphenyl, biphenylyl, terphenyl, quaterphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis-or trans-indenofluorenyl, triindenyl, isotridecyl, spirotrimerization indenyl, spiroisotridecyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, pyridyl, quinolyl, isoquinolyl, acridinyl, phenanthridinyl, benzo-5, 6-quinolyl, benzo-6, 7-quinolyl, benzo-7, 8-quinolyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthoimidazolyl, phenanthroimidazolyl, pyridoimidazolyl, pyrazinoimidazolyl, quinoxalinyl, oxazolyl, benzoxazolyl, naphthooxazolyl, anthracenyl, phenanthroizolyl, 1, 2-thiazolyl, 1, 3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyrazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1, 5-diazenanthrayl, 2, 7-diazapyl, 2, 3-diazapyl, 1, 6-diazapyl, 1, 8-diazapyl, 4,5,9, 10-tetraazapiperazinyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, Azacarbazolyl, benzocarbazinyl, phenanthrolinyl, 1,2, 3-triazolyl, 1,2, 4-triazolyl, benzotriazolyl, 1,2, 3-oxadiazolyl, 1,2, 4-oxadiazolyl, 1,2, 5-oxadiazolyl, 1,2, 3-thiadiazolyl, 1,2, 4-thiadiazolyl, 1,2, 5-thiadiazolyl, 1,3, 4-thiadiazolyl, 1,3, 5-triazinyl, 1,2, 4-triazinyl, 1,2, 3-triazinyl, tetrazolyl, 1,2,4, 5-tetrazinyl, 1,2,3, 4-tetrazinyl, 1,2,3, 5-tetrazinyl, purinyl, pteridinyl, indolizinyl, benzothiadiazolyl, 9-dimethylazinyl, halobenzene, cyanobenzene, One kind of trifluoromethyl benzene or the combination of two kinds of substituent groups.

2. The organic compound according to claim 1, selected from the following compounds of specific structure:

3. use of the organic compound according to claim 1 or 2 as a light-emitting layer material or as a fluorescence-sensitizing material in an organic electroluminescent device.

4. An organic electroluminescent device comprising a first electrode, a second electrode and one or more organic layers interposed between said first and second electrodes, characterized in that said organic layers comprise at least one organic compound according to any one of claims 1 to 2.