Boron-containing organic compounds and light-emitting devices

Abstract

The present application provides a boron-containing organic compound and a light-emitting device, wherein the boron-containing organic compound is a compound represented by formula (III): wherein R1 to R 14 is selected from any one of a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group; and M is a substituted or unsubstituted C6 to C40 aryl group.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202111418443.9 (Application Date: November 26, 2021, Invention Name: Boron-containing organic compound and light-emitting device) for invention patents. TECHNICAL FIELD

[0002] The present application relates to the technical field of organic optoelectronics, in particular to a boron-containing organic compound and a light-emitting device. BACKGROUND

[0003] Organic electroluminescent devices have a series of advantages such as self-luminescence, low-voltage driving, full solidification, wide viewing angle, simple composition and process, etc. Compared with liquid crystal displays, organic electroluminescent devices do not need a backlight. Therefore, organic electroluminescent devices have a wide application prospect.

[0004] An organic electroluminescent device generally includes an anode, a metal cathode, and an organic layer sandwiched between them. The organic layer mainly includes 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. In addition, the light-emitting layer mostly adopts a host-guest structure. That is, the light-emitting material is doped in the host material at a certain concentration to avoid concentration quenching and triplet-triplet annihilation, and to improve the light-emitting efficiency. In the structure of the organic electroluminescent device, if a voltage is applied between the two electrodes, electrons and holes are injected and transported from the cathode and the anode into the light-emitting layer to form excitons, and the excitons emit light when they fall to the ground state again.

[0005] In recent years, some properties unique to boron have attracted great interest in boron-containing π-conjugated materials. In molecular design, by reasonably utilizing the characteristics of boron elements, they can be introduced into different positions of π-conjugated systems to obtain different structural types of organic π-conjugated new materials with unique photoelectric properties, such as electron transport materials and light-emitting materials in organic electroluminescent devices, chemical sensor materials, and organic photovoltaic materials, etc.

[0006] The currently commercially used blue boron-nitrogen-based material is a multi-resonant thermally activated delayed fluorescence material (MR-TADF). Although this material can theoretically utilize triplet states to improve the utilization rate of excitons to 100%, the currently commercialized blue boron-nitrogen-based triplet exciton has a long lifetime, which leads to a short device lifetime and a large efficiency roll-off under high current density. Therefore, many panel manufacturers choose to improve the device lifetime and reduce the device efficiency, that is, only the singlet state of the material is used. How to use the triplet state of this material in industry to improve the device efficiency and ensure a long device lifetime still faces many key problems. In addition, the currently commercialized blue boron-nitrogen-based molecule has a good planar structure, and the self-quenching effect is very serious under high concentration doping. Therefore, the device needs to be prepared at a very low doping concentration, which seriously affects the operability of the process. SUMMARY

[0007] The present application provides a boron-containing organic compound and a light-emitting device, which introduces a steric hindrance group and a low triplet group: 1) the introduction of a steric hindrance group forms a twisted three-dimensional structure, which can effectively avoid the occurrence of concentration quenching effect of multi-resonant thermally activated delayed fluorescence material caused by its own planar structure; 2) the introduction of a low triplet group can effectively reduce the triplet energy of the boron-containing organic compound of the present application, increase the energy difference between the singlet state and the triplet state of the material, effectively inhibit the process of long-lifetime triplet exciton returning to the singlet state through the inverse intersystem crossing, prevent the formation of such long-lifetime exciton, and thus improve the device performance while ensuring a long device lifetime.

[0008] To achieve the above-mentioned purpose, as an embodiment of one aspect of the present application, the present application provides a boron-containing organic compound, which includes a compound represented by any one of formula (I) to formula (III):

[0009]

[0010]

[0011] R1~R 14are independently selected from any one of the following groups: hydrogen atom, deuterium atom, halogen, cyano, NO2, N(R)2, OR, SR, C(=O)R, P(=O)R, Si(R)3, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C2-C20 alkynyl, substituted or unsubstituted C6-C40 aryl, substituted or unsubstituted C5-C40 heteroaryl, wherein R is selected from any one of the following groups: hydrogen atom, deuterium atom, fluorine atom, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl; M is substituted or unsubstituted C6-C48 aryl; X1, X2 are independently selected from any one of the following groups: O, S, N-Y, C(Y)2, wherein Y is selected from any one of the following groups: substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C40 aryl or substituted or unsubstituted C5-C40 heteroaryl.

[0012] As an embodiment of another aspect of the present application, there is provided a light-emitting device comprising a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode, the organic layer containing at least one of the above-mentioned boron-containing organic compounds.

[0013] The present application improves the utilization of excitons of the compound by the triplet-triplet annihilation (TTA) effect without changing the narrow emission peak, high thermal stability, good transport performance and high fluorescence quantum yield of the boron-containing compound, and ultimately improves the device efficiency by introducing an aromatic group at the para position of the boron element. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the fluorescence spectrum of compound 1-1 and BD2 in toluene solution in the embodiment of the present application;

[0015] Figure 2 is the fluorescence spectrum of compound 2-6, 2-1 and BD1 in toluene solution in the embodiment of the present application;

[0016] Figure 3 is a structural diagram of an organic electroluminescent device in the embodiment of the present application.

[0017] REFERENCE NUMERALS:

[0018] 1 - substrate, 2 - anode, 3 - hole injection layer, 4 - hole transport layer, 5 - electron blocking layer, 6 - light-emitting layer, 7 - hole blocking layer, 8 - electron transport layer, 9 - electron injection layer, 10 - cathode. DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to specific embodiments and with reference to the drawings.

[0020] The pπ-π* conjugation effect between the empty p orbital of boron atom and the π* orbital of π-conjugated system can introduce boron into the π-conjugated system to endow the system with some unique photoelectric properties. The construction of π-conjugated photoelectric functional materials using boron is mainly based on the following three characteristics of boron element: (1) special orbital interaction: the pπ-π* conjugation can be formed between the empty p orbital of boron element and the π* orbital of π-conjugated system, thereby lowering the lowest unoccupied orbital (LUMO) energy level of the system; (2) Lewis acidity: due to the existence of the empty p orbital, boron can easily complex with Lewis base (such as fluoride ion) and break the pπ-π* conjugation, thereby causing significant changes in the photoelectric properties of the corresponding system; (3) large steric hindrance effect: due to the existence of the empty p orbital, in order to improve the stability of the π-conjugated organic boron compound, a bulky aromatic group usually needs to be introduced on the boron atom.

[0021] According to the overall inventive concept of one aspect of the present application, there is provided a boron-containing organic compound, including a compound shown in any one of formula (I) to formula (III):

[0022]

[0023]

[0024] R1~R 14 are each selected from any one of a hydrogen atom, a deuterium atom, a halogen, a cyano group, a NO2 group, a N(R)2 group, an OR group, an SR group, a C(=O)R group, a P(=O)R group, a Si(R)3 group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C2-C20 alkynyl group, a substituted or unsubstituted C6-C40 aryl group, and a substituted or unsubstituted C5-C40 heteroaryl group, wherein R is selected from any one of a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C5-C30 heteroaryl group; M is a substituted or unsubstituted C6-C48 aryl group; X1 and X2 are each selected from any one of O, S, N-Y, and C(Y)2, wherein Y is selected from any one of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C40 aryl group, and a substituted or unsubstituted C5-C40 heteroaryl group.

[0025] The present application introduces aromatic groups on boron elements, forms pπ-π* conjugation between the outermost empty p orbit and the π* orbit of the π-conjugated system, so that the conjugated system has photoelectric properties, and the boron-containing compound has narrow emission peak, high thermal stability, good transmission performance and high fluorescence quantum yield.

[0026] In the present application, the term "substituted or unsubstituted" means that a certain group or ring system can be substituted by one or more groups or ring systems, or can remain unsubstituted.

[0027] According to an embodiment of the present application, the boron-containing organic compound can have a structure represented by the following general formula (S-1) to (S-6) (not limited to this formula), wherein in the general formula (S-6), when both are N-Y, the two Ys can be the same or different. Preferably, Y is selected from any one of the following groups: substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C5-C18 heteroaryl.

[0028]

[0029] According to an embodiment of the present application, R1-R 14 selected from any one of the following groups: substituted or unsubstituted alkyl, preferably C1-C6; substituted or unsubstituted alkenyl, preferably C2-C6; substituted or unsubstituted alkynyl, preferably C2-C6; substituted or unsubstituted aryl, preferably C6-C18; substituted or unsubstituted heteroaryl, preferably C5-C18.

[0030] According to an embodiment of the present application, the heteroatom in the C5-C40 heteroaryl is selected from any one of the following groups: N, O, S, P, As, Si, preferably N, O, S; the number of heteroatoms in the C5-C40 heteroaryl is 1-10, preferably 1-5.

[0031] According to an embodiment of the present application, the C6-C48 aryl in M is selected from any one of the following groups: monocyclic benzene ring, bicyclic biphenyl ring, condensed bicyclic naphthalene ring, tricyclic terphenyl ring (m-terphenyl, o-terphenyl, p-terphenyl), condensed tricyclic acenaphthene ring, fluorene ring, phenalene ring, phenanthrene ring, fluoranthene, condensed tetracyclic triphenylene ring, pyrene ring, naphthacene ring, condensed pentacyclic perylene ring, pentacene ring.

[0032] According to an embodiment of the present application, the boron-containing organic compound of the present application is selected from any one of the following compounds:

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] According to embodiments of the present application, M is selected from any one of the following groups:

[0059]

[0060]

[0061]

[0062] Among them, A1~A6, B1~B9, C1~C8, D1~D9, E1~E6, F1~F7, G1~G 10 H1~H9, K1~K 12 L1~L6, M1~M 12 N1~N 10 O1~O 17 P1~P 15 Q1~Q 15 I i ~I 15 R1~R 15 S1~S 13 T1~T 13 U1~U 12 V1~V 12 W1~W 17 X1~X 15 Y1~Y 15 Z1~Z 15 J1~J 15 ,Aa1~Aa 15 Bb1~Bb 15 Cc l ~Cc 16 , Dd1~Dd 15 ,Ee1~Ee 15 , Ff1~Ff 15 Gg1~Gg 15 Hh1~Hh 17 ,Ii1~Ii 15 Jj1~Jj 15 Each group is selected from any one of the following groups: hydrogen atom, deuterium atom, fluorine atom, cyano group, substituted or unsubstituted C1-C20 alkyl group, substituted or unsubstituted C6-C30 aryl group, or substituted or unsubstituted C5-C30 heteroaryl group.

[0063] According to an embodiment of the present invention, "the position of the dotted line can be moved" means that a certain group can be connected to the main body at multiple different positions, such as one or two positions.

[0064] According to an embodiment of the application, the C1-C20 alkyl group is selected from any one of the following groups: methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, n-hexyl, n-heptyl, 2-methylhexyl, n-octyl, i-octyl, t-octyl, 2-ethylhexyl, 3-methylheptyl, n-nonyl, n-decyl, hexadecyl, octadecyl, eicosyl, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, cycloheptyl, cyclooctyl.

[0065] According to an embodiment of the application, the C2-C20 alkenyl group is linear, branched or cyclic.

[0066] According to an embodiment of the application, the C2-C20 alkenyl group is linear, branched or cyclic.

[0067] According to an embodiment of the application, the C2-C20 alkenyl group is linear, branched or cyclic.

[0068] According to an embodiment of the application, the C2-C20 alkynyl group is linear, branched or cyclic.

[0069] According to an embodiment of the application, the C2-C20 alkynyl group is linear, branched or cyclic.

[0070] According to an embodiment of the application, the C6-C40 aryl group is selected from any one of the following groups: phenyl, naphthyl, anthryl, benzanthryl, phenanthryl, benzphenanthryl, pyrenyl, perylenyl, fluoranthenyl, benzofluoranthenyl, naphthacene, pentaphene, benzopyrenyl, biphenyl, biphenyl, terphenyl, quaterphenyl, quinquephenyl, triphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis or trans indenofluorenyl, cis or trans monobenzindenofluorenyl, cis or trans dibenzindenofluorenyl, triindenyl, isotriindenyl, spirotrindenyl, spiroisotriindenyl.

[0071] According to an embodiment of the application, the C6-C40 aryl group is preferably phenyl, naphthyl, anthryl, phenanthryl, benzanthryl, benzphenanthryl.

[0072] According to an embodiment of the present application, the C5-C40 heteroaryl group is selected from any one of the following: furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl, indolocarbazolyl, indenocarbazolyl, pyridyl, quinolyl, isoquinolyl, acridinyl, phenanthridinyl, benzo-5,6-quinolyl, benzo-6,7-quinolyl, benzo-7,8-quinolyl, phenoxazinyl, phenoxazinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthimidazolyl, phenanthroimidazolyl, pyridimidazolyl, pyrazimidazolyl, quinoximidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthroxazolyl, phenanthroxazolyl, isoxazolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthryl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazaperylenyl, pyrazinyl, phenoxazinyl, phenoxazinyl, phenothiazinyl, fluoran ring, naphthidinyl, azacarbazolyl, benzocarbolinyl, phenanthroline, 1,2,3-triazolyl, 1,2,4-triazolyl, benzotriazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-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, and the like, preferably phenyl, naphthyl, anthryl, phenanthryl, benzanthryl, benzphenanthryl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl.

[0073] According to an embodiment of the present application, the C6-C40 heteroaryl group is preferably furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl, more preferably carbazolyl.

[0074] According to an embodiment of the present application, the substituents in the substituted C6-C40 aryl group and the substituted C5-C40 heteroaryl group are selected from any one of the following: deuterium atom, halogen, amino group, hydroxyl group, cyano group, C1-C6 alkyl group.

[0075] According to the embodiments of the present application, the number of substituents in C6-C40 aryl and C5-C40 heteroaryl is 1-5, preferably 1-3.

[0076] According to the embodiments of the present application, C1-C6 alkyl is selected from any one of the following groups: methyl, tert-butyl.

[0077] The present application will be described in detail with specific embodiments.

[0078] The compound 1-1 is synthesized by the following synthetic route

[0079] Step one: synthesis of intermediate 1-1-1

[0080]

[0081] Under nitrogen atmosphere, a three-necked flask equipped with reflux condenser was charged with 5-bromo-l,3-difluoro-2-iodobenzene (15.9 g, 50.0 mmol), 3,6-di-tert-butylcarbazole (27.86 g, 100.0 mmol), sodium hydride (3.00 g, 125.0 mmol) and DMF (200 mL) successively, and heated to reflux for 6 h. After the reaction was completed, the system was cooled to room temperature. A large amount of water was added, and white precipitate was generated, which was collected by suction filtration. The precipitate was washed with water and 50% methanol solution successively. Finally, the obtained filter cake was dissolved in appropriate amount of dichloromethane, and further purified by column chromatography (the mobile phase was petroleum ether and dichloromethane in a volume ratio of 3:1), to obtain white solid 37.6 g, with a yield of 90%.

[0082] The obtained sample was detected by mass spectrometry, and the result was: MS (EI): m / z 836.22 [M + ] ; C 46 H 50 BIN2 (%): calculated value: C, 65.95; H, 6.02; N, 3.34; measured value: C, 65.92; H, 5.99; N, 3.31.

[0083] Step two: synthesis of intermediate 1-1-2

[0084]

[0085] To a clean 100 mL three-necked flask, 3.6 g (5.0 mmol) of intermediate 1-1-2, 1.3 g (12.4 mmol) of anhydrous sodium carbonate, 2.5 g (5.3 mmol) of deuterated phenylanthracene boronic acid, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium and 45 mL of mixed solvent (toluene:water:ethanol = 30:8:7 by volume) were added successively under nitrogen atmosphere. The system was heated to reflux and reacted overnight at reflux. After the reaction was completed, the heating was stopped and the reaction system was cooled to room temperature spontaneously. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried with anhydrous sodium sulfate, concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, mobile phase: petroleum ether and dichloromethane = 3:2 by volume) to obtain a yellow solid 3.5 g in a yield of 80%.

[0086] The obtained sample was detected by mass spectrometry, and the results were as follows: MS (EI): m / z 720.31 [M + ] ; C 46 H 48 BBrN2(%) calculated: C, 76.78; H, 6.72; N, 3.89; found: C, 76.73; H, 6.69; N, 3.84.

[0087] Step three: synthesis of compound 1-1

[0088]

[0089] To a clean 100 mL three-necked flask, 3.6 g (5.0 mmol) of intermediate 1-1-2, 1.3 g (12.4 mmol) of anhydrous sodium carbonate, 2.5 g (5.3 mmol) of deuterated phenylanthracene boronic acid, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium and 45 mL of mixed solvent (toluene:water:ethanol = 30:8:7 by volume) were added successively under nitrogen atmosphere. The system was heated to reflux and reacted overnight at reflux. After the reaction was completed, the heating was stopped and the reaction system was cooled to room temperature spontaneously. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried with anhydrous sodium sulfate, concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, mobile phase: petroleum ether and dichloromethane = 3:2 by volume) to obtain a yellow solid 3.5 g in a yield of 80%.

[0090] The obtained sample was detected by mass spectrometry, and the results were as follows: MS (EI): m / z 720.31 [M + ]. Elemental analysis calculated C 66 H 56D5BN2(%) calcd: C, 88.27; H, 7.41; B, 1.20; N, 3.12; found: C, 88.23; H, 7.37; B, 1.15; N, 3.07.

[0091] The compound 2-6 was synthesized by the following route

[0092] Step one: synthesis of intermediate 2-6-1

[0093]

[0094] Into a three-necked flask equipped with a reflux condenser, 5-bromo-l,3-difluoro-2-iodobenzene (15.9 g, 50.0 mmol), di(4-tert-butylphenyl)amine (28.07 g, 100.0 mmol), sodium hydride (3.00 g, 125.0 mmol) and DMF (200 mL) were added successively under nitrogen atmosphere and heated to reflux for 6 h. After the reaction was completed, the system was cooled to room temperature. A large amount of water was added and white precipitate was formed, which was collected by suction filtration. The precipitate was washed successively with water and 50% methanol solution. Finally, the obtained filter cake was dissolved in appropriate amount of dichloromethane and further purified by column chromatography (the mobile phase was petroleum ether and dichloromethane in the volume ratio of 3:1) to give 39 g of white solid with a yield of 95%.

[0095] The obtained sample was detected by mass spectrometry and the result was: MS (EI): m / z 840.25 [M + ] ; C 46 H 54 BrIN2(%) calcd: C, 65.64; H, 6.47; N, 3.33; found: C, 65.59; H, 6.45; N, 3.31.

[0096] Step two: synthesis of intermediate 2-6-2

[0097]

[0098] To a clean 100 mL three-necked flask, 3.62 g (5.0 mmol) of intermediate 2-6-2, 1.3 g (12.4 mmol) of anhydrous potassium carbonate, 1.9 g (5.00 mmol) of 1-pyreneboronate, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium and 45 mL of mixed solvent (toluene:water:ethanol = 30:8:7 by volume) were added successively under nitrogen atmosphere. The system was heated to reflux and the reaction was allowed to proceed overnight at reflux. After the reaction was completed, the heating was stopped and the reaction system was allowed to cool to room temperature. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent: petroleum ether and dichloromethane = 3:2 by volume) to give a yellow solid 2.7 g in a yield of 60%.

[0099] The results of the mass spectrometric detection of the sample obtained were: MS (EI): m / z 722.34 [M + ] ; C 46 H 52 BBrN2(%) calculated: C, 76.78; H, 6.72; N, 3.89; found: C, 76.75; H, 6.65; N, 3.87.

[0100] Step three: synthesis of compound 2-6

[0101]

[0102] To a clean 100 mL three-necked flask, 3.62 g (5.0 mmol) of intermediate 2-6-2, 1.3 g (12.4 mmol) of anhydrous potassium carbonate, 1.9 g (5.00 mmol) of 1-pyreneboronate, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium and 45 mL of mixed solvent (toluene:water:ethanol = 30:8:7 by volume) were added successively under nitrogen atmosphere. The system was heated to reflux and the reaction was allowed to proceed overnight at reflux. After the reaction was completed, the heating was stopped and the reaction system was allowed to cool to room temperature. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent: petroleum ether and dichloromethane = 3:2 by volume) to give a yellow solid 2.7 g in a yield of 60%.

[0103] The results of the mass spectrometric detection of the sample obtained were: MS (EI): m / z 722.34 [M + ]. Elemental analysis calculated C 66 H 59BN2(%) : C, 88.97; H, 6.67; N, 3.14; Found: C, 88.80; H, 6.61; N, 3.10.

[0104] The compound 2-1 was synthesized by the following route

[0105]

[0106] To a clean 100 mL three-necked flask, 3.62 g (5.0 mmol) of intermediate 2-6-2, 1.3 g (12.4 mmol) of anhydrous sodium carbonate, 1.64 g (5.00 mmol) of 1-pyreneboronic acid, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium and 45 mL of mixed solvent (toluene: water: ethanol = 30:8:7 by volume) were added successively under nitrogen atmosphere. The system was heated to reflux and reacted overnight at reflux. After the reaction was completed, the heating was stopped and the reaction system was cooled to room temperature spontaneously. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent: petroleum ether: dichloromethane = 3:2 by volume) to obtain 2.5 g of yellow solid, with a yield of 60%.

[0107] The result of mass spectrometry detection of the obtained sample was: MS (EI): m / z 844.49 [M + ]Elemental analysis calculated value C 62 H 61 BN2(%) : C, 88.97; H, 6.67; N, 3.14; Found: C, 88.80; H, 6.61; N, 3.10.

[0108] The compound 2-7 was synthesized by the following route

[0109]

[0110] To a clean 100 mL three-necked flask, 3.62 g (5.0 mmol) of intermediate 2-6-2, 1.3 g (12.4 mmol) of anhydrous sodium carbonate, 1.80 g (5.00 mmol) of 9,9'-spirobifluorene-3-boronic acid, 68.3 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium, and 45 mL of mixed solvent (toluene:water:ethanol = 30:8:7 by volume) were sequentially added under nitrogen atmosphere. The system was heated to reflux, and the reaction was allowed to proceed overnight at reflux. After the reaction was completed, the heating was stopped, and the reaction system was allowed to cool to room temperature. The reaction solution was poured into about 200 mL of water, and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and further purified by column chromatography (350 mesh silica gel, eluent: petroleum ether:dichloromethane = 3:2 by volume) to obtain 3.1 g of yellow solid, with a yield of 65%.

[0111] The obtained sample was detected by mass spectrometry, and the results were as follows: MS (EI): m / z 958.49 [M + ]。 Elemental analysis calculated value C 71 H 67 BN2 (%) : C, 88.91; H, 7.04; N, 2.92; measured value: C, 88.90; H, 7.02; N, 2.90.

[0112] According to the general inventive concept of another aspect of the present application, there is provided a light-emitting device including a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode, the organic layer containing at least one of the above-mentioned boron-containing organic compounds.

[0113] The boron-containing organic compounds of the present application can be used in aspects of organic electroluminescent devices, organic solar cells, organic diodes, etc. The organic light-emitting device made of the above-mentioned polycyclic boron-containing compounds exhibits advantages of high luminous efficiency, long service life, low driving voltage, narrow half-peak width, high color purity, etc., and is an excellent organic electroluminescent material, and finally the device performance of the material is further improved in the OLED device.

[0114] Figure 3 is a configuration diagram of an organic electroluminescent device in an example of the present application. As shown in Figure 3 An anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9, and a cathode 10 are sequentially disposed on a substrate 1.

[0115] According to the embodiment of the present application, the organic electroluminescent device can be manufactured by sequentially stacking the first electrode, the organic layer, and the second electrode on the substrate. The specific manufacturing process is as follows: a metal or a metal oxide having conductivity or an alloy thereof is evaporated on the substrate by a PVD (Physical Vapor Deposition) method such as a sputtering method or an electron beam evaporation method to form an anode, and then an organic layer including a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer is formed on the anode, and then a substance that can be used as a cathode is evaporated on the organic layer.

[0116] According to the embodiment of the present application, the configuration of the organic electroluminescent device can omit the hole injection layer 3 between the anode 2 and the hole transport layer 4, the hole blocking layer 7 between the light emitting layer 6 and the electron transport layer 8, and the electron injection layer 9 between the electron transport layer 8 and the cathode 10, and become a configuration in which the anode 2, the hole transport layer 4, the light emitting layer 6, the electron transport layer 8, and the cathode 10 are sequentially provided on the substrate 1.

[0117] According to the embodiment of the present application, the anode material of the organic electroluminescent device is selected from any one of the following: (1) metals such as vanadium, chromium, copper, zinc, gold, or alloys thereof, for example, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), ZnO:Al, SnO2:Sb; and (2) conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline. Preferably, indium tin oxide (ITO).

[0118] According to the embodiment of the present application, the material of the hole injection layer of the organic electroluminescent device is selected from any one of the following: a porphyrin compound represented by copper phthalocyanine, a naphthalene diamine derivative, a star-shaped triphenylamine derivative, an aromatic amine compound having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group not containing a hetero atom in a molecule, a triphenylamine trimer and a tetramer, a hexacyanobenzo[a]phenanthroline acceptor-type heterocyclic compound, and a coating-type polymer material. The hole injection layer material of the organic electroluminescent device can be formed into a thin film by an evaporation method, a spin coating method, or an inkjet method.

[0119] According to the embodiment of the present application, the material of the hole transport layer of the organic electroluminescent device is selected from any one of the following: (1) a compound containing a m-carbazolyl phenyl group, such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), (2) a benzidine derivative, such as N,N,N',N'-tetraphenylbenzidine; (3) 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC); (4) various triphenylamine trimers and tetramers; (4) 9,9',9"-triphenyl-9H,9'H,9"H-3,3':6',3"-tris-carbazole (Tris-PCz). The above-mentioned materials can be used in the form of a single layer formed by being deposited alone or mixed with other materials, and can also be used in the form of a stacked structure of layers formed by being deposited alone, a stacked structure of layers formed by being mixed, or a stacked structure of layers formed by being deposited alone and layers formed by being mixed. The above-mentioned materials can be formed into a thin film by an evaporation method, a spin coating method, an inkjet method, or the like.

[0120] According to the embodiment of the present application, in the hole injection layer or the hole transport layer of the organic electroluminescent device, a substance further p-doped with a material generally used in the layer, such as tribromoaniline hexachloroantimony, an axeridine derivative, or the like, a high molecular compound having a structure of a benzidine derivative such as TPD in a partial structure, or the like can also be used.

[0121] According to the embodiment of the present application, the material of the electron blocking layer of the organic electroluminescent device is selected from any one of the following: 3,3'-di(N-carbazolyl)-1,1'-biphenyl (mCBP), 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (mCP), 2,2-bis(4-carbazol-9-ylphenyl)adamantane (Ad-Cz), and other carbazole derivatives; a compound having a triphenylsilyl group and a triarylamine structure represented by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene; a monoamine compound having a high electron blocking property, various triphenylamine dimers, and the like. The above-mentioned materials can be used in the form of a single layer formed by being deposited alone or mixed with other materials, and can also be used in the form of a stacked structure of layers formed by being deposited alone, a stacked structure of layers formed by being mixed, or a stacked structure of layers formed by being deposited alone and layers formed by being mixed. These materials can be formed into a thin film by an evaporation method, a spin coating method, an inkjet method, or the like.

[0122] According to the embodiment of the present application, the material of the light emitting layer of the organic electroluminescent device is selected from any one of the following: a light emitting material containing an organic electroluminescent compound (boron-containing organic compound) represented by Formula (I) to Formula (III), a metal complex of a hydroxyquinoline derivative such as Alq3, various metal complexes, a compound having a pyrimidine ring structure, an anthracene derivative, a distyrylbenzene derivative, a pyrene derivative, an oxazole derivative, and a poly-p-phenylenevinylene derivative.

[0123] According to the embodiment of the present application, the light emitting layer of the organic electroluminescent device can be composed of a host material and a dopant material. The host material can be selected from any one of the following: mCBP, mCP, an anthracene derivative, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, a heterocyclic compound having an indole ring as a partial structure of a fused ring, and the like. The dopant material can be selected from any one of the following: a pyrene derivative, an anthracene derivative, quinacridone, coumarin, rubrene, perylene and its derivatives, a benzopyran derivative, a rhodamine derivative, an aminostyryl derivative, a spirobifluorene derivative, and the like, and preferably a light emitting material containing an organic electroluminescent compound (boron-containing organic compound) represented by Formula (I) to Formula (III). The doping weight ratio of the organic electroluminescent compound of the present application is preferably 0.1 to 50%, more preferably 0.2 to 20%, and particularly preferably 0.5 to 10%.

[0124] According to the embodiment of the present application, the material of the hole blocking layer of the organic electroluminescent device is selected from any one of the following: 2,4,6-tris(3-phenyl)-1,3,5-triazine (T2T), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), a metal complex of a quinolinol derivative such as aluminum(III)bis(2-methyl-8-hydroxyquinolinato)-4-phenylphenolate (BAlq), and various rare earth complexes, an oxazole derivative, a triazole derivative, a triazine derivative, and the like. The above-mentioned materials can be formed into a film alone, or can be used in the form of a single layer formed by mixing with other materials, or can be formed into a stacked structure of layers formed by being deposited alone, a stacked structure of layers formed by being mixed and deposited, or a stacked structure of layers formed by being deposited alone and layers formed by being mixed and deposited. These materials can be formed into a thin film by a method such as an evaporation method, a spin coating method, an inkjet method, or the like.

[0125] According to the embodiment of the present application, the material of the electron transport layer of the organic electroluminescent device is selected from any one of the following: metal complexes of hydroxyquinoline derivatives such as BAIq; various metal complexes; triazole derivatives; triazine derivatives; oxadiazole derivatives; pyridine derivatives; beryllium bis(10-hydroxybenzo[H]quinoline) (Be(bq2)); benzimidazole derivatives such as 2-[4-(9,10-dinaphtho-2-anthracen-2-yl)phenyl]-l-phenyl-lH-benzimidazole (ZADN); thiadiazole derivatives; anthracene derivatives; carbodiimide derivatives; quinoxaline derivatives; pyridoindole derivatives; phenanthroline derivatives; and thioxyl derivatives. The above materials can be used in the form of a single layer formed by being deposited alone or by being mixed with other materials, or in the form of a stacked structure of layers formed by being deposited alone, a stacked structure of layers formed by being mixed, or a stacked structure of layers formed by being deposited alone and layers formed by being mixed. These materials can be formed into thin films by a method such as an evaporation method, a spin coating method, or an inkjet method.

[0126] According to the embodiment of the present application, the material of the electron injection layer of the organic electroluminescent device is selected from any one of the following: alkali metal salts such as lithium fluoride and cesium fluoride; alkaline earth metal salts such as magnesium fluoride; metal complexes of hydroxyquinoline derivatives such as lithium hydroxyquinolinate; and metal oxides such as aluminum oxide.

[0127] According to the embodiment of the present application, in the electron injection layer or the electron transport layer of the organic electroluminescent device, a material formed by further doping a metal such as cesium or a triarylphosphine oxide derivative into a material generally used in the layer can be used.

[0128] According to the embodiment of the present application, the material of the hole transport layer, the electron blocking layer, the light emitting layer, the hole blocking layer, and the electron transport layer of the organic electroluminescent device is selected from any one of the following: metal complexes of hydroxyquinoline derivatives such as BAIq; various metal complexes; triazole derivatives; triazine derivatives; oxadiazole derivatives; pyridine derivatives; beryllium bis(10-hydroxybenzo[H]quinoline) (Be(bq2)); benzimidazole derivatives such as 2-[4-(9,10-dinaphtho-2-anthracen-2-yl)phenyl]-l-phenyl-lH-benzimidazole (ZADN); thiadiazole derivatives; anthracene derivatives; carbodiimide derivatives; quinoxaline derivatives; pyridoindole derivatives; phenanthroline derivatives; and thioxyl derivatives.

[0129] According to the embodiment of the present application, the material of the cathode of the organic electroluminescent device is selected from any one of the following: electrode materials having a low work function such as aluminum and magnesium, or alloys having a low work function such as a magnesium-silver alloy, a magnesium-indium alloy, and an aluminum-magnesium alloy.

[0130] According to the embodiment of the present application, the substrate of the organic electroluminescent device can use a substrate used in conventional organic light emitting devices, for example, a glass or a plastic, and a glass substrate is preferably used.

[0131] The organic electroluminescent device according to the present application will be described in detail below with reference to specific examples.

[0132] Preparation of the organic electroluminescent device 1 (organic EL device 1)

[0133] Hole injection layer 3, hole transport layer 4, electron blocking layer 5, light-emitting layer 6, hole blocking layer 7, electron transport layer 8, electron injection layer 9, and cathode 10 are sequentially formed on a transparent anode 2 pre-formed on a glass substrate 1 to prepare a material as shown in the image. Figure 3 The organic electroluminescent device shown is fabricated as follows: A glass substrate with a 100 nm thick ITO film is ultrasonically treated in Decon 90 alkaline cleaning solution, rinsed in deionized water, cleaned three times each in acetone and ethanol, baked in a clean environment until all moisture is removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The glass substrate with the ITO electrode is then placed in a vacuum chamber and evacuated to a vacuum level of 4 × 10⁻⁶. -4 ~2×10 -5 Pa. Then, on the glass substrate with the ITO electrode, 50% HIL1 / 50% HTL1 was deposited at a deposition rate of 0.2 nm / s to form a 10 nm thick layer as a hole injection layer. On the hole injection layer, HTL1 was deposited at a deposition rate of 2.0 nm / s to form a 30 nm thick layer as a hole transport layer. On the hole transport layer, three-source co-evaporation was performed with deposition rates of 1.6 nm / s and 0.4 nm / s for BH1 and 5Cz-TRZ as host materials, and a deposition rate of 0.04 nm / s for 1-1 as a dopant, to form a 20 nm thick layer as a light-emitting layer, with a 1-1 doping weight ratio of 2 wt%. On the light-emitting layer, HBL1 was deposited at a deposition rate of 2.0 nm / s to form a 20 nm thick layer as a hole blocking layer. On the hole blocking layer, 50% ETL1 / 50% Liq was deposited at a deposition rate of 2.0 nm / s to form a 40 nm thick electron transport layer. On the electron transport layer, 8-hydroxyquinoline-lithium (Liq) was deposited at a deposition rate of 0.2 nm / s to form a 2 nm thick electron injection layer. Finally, aluminum was deposited at a deposition rate of 3.0 nm / s or higher to form a 100 nm thick cathode.

[0134] Fabrication of organic electroluminescent devices 2-3 (organic EL devices 2-3)

[0135] Organic EL devices 2 to 3 were fabricated under the same conditions as organic EL device 1, except that the compounds listed in Tables 1 and 2 below were used to replace the compounds in each layer of organic electroluminescent device 1 (organic EL device 1).

[0136] Comparative Examples 1-2 of Organic Electroluminescent Devices

[0137] Except for replacing the compounds in each layer of the organic electroluminescent device 1 (organic EL device 1) with the compounds listed in Table 1 below, comparative organic EL devices 1 to 2 were fabricated under the same conditions as organic EL device 1.

[0138] Table 1

[0139]

[0140]

[0141] The structures of the compounds involved in the examples are as follows:

[0142]

[0143] The light emission characteristics of organic EL devices 1-3 and Comparative Examples 1-2 were measured under ambient air and when a DC voltage was applied. The measurement results are shown in Tables 2 and 3.

[0144] Table 2

[0145]

[0146]

[0147] Table 3

[0148]

[0149] The current-luminosity-voltage characteristics of the device were measured using a Keithley source measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode. The electroluminescence spectrum was measured using a Photo Research PR655 spectrometer. The external quantum efficiency of the device was calculated using the method described in Adv. Mater., 2003, 15, 1043-1048.

[0150] From Table 2 and Figure 1 As can be seen, compared with BD2, the boron-containing compound 1-1 of the present invention introduces a low triplet state deuterated phenyl anthracene on the benzene ring at the B position. The fluorescence emission peak and half-maximum width of the material do not change significantly. In the end, the turn-on voltage of the device is significantly reduced, the lifetime and efficiency of the device are improved, and the efficiency roll-off of the device under high current density is reduced.

[0151] From Table 2 and Figure 2It can be seen that compared with BD1, the boron-containing compounds 2-6 and 2-1 of the present application respectively introduce a low-triplet pyrene group on the benzene ring at the para position of B, and the fluorescence emission peak and half-width of the material do not change significantly, which ultimately significantly reduces the turn-on voltage of the device, improves the lifetime and efficiency of the device, and reduces the efficiency roll-off of the device under high current density.

[0152] As can be seen from Table 3, compared with BD1, the boron-containing compound 2-7 of the present application introduces a bulky stereogenic group, and the device performance is significantly improved, and the turn-on voltage of the device is significantly reduced. At the same time, under different doping concentrations, the device efficiency does not change significantly, in contrast, the device efficiency of the comparative material BD1 is quenched more severely with the increase of doping concentration.

[0153] By introducing anthracene and pyrene groups on the aromatic ring at the para position of B, the present application avoids the generation of long-lived triplet excitons, and at the same time, the fluorescence peak of the material does not change significantly, and finally in the OLED device, the device performance of the material is further improved. In addition, the preparation method of the polycyclic boron-containing compound of the present application is simple, the raw materials are easy to obtain, and no isomer is produced, the purification process is simple, and it can meet the development needs of industrialization.

[0154] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the present application, and it should be understood that the above description is only for specific embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A light-emitting device for emitting blue light, comprising a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode, characterized in that, The organic layer is a light-emitting layer, comprising BH1 and optional 5Cz-TRZ as host materials, and at least one boron-containing organic compound or compound 2-7 having the structure shown in formula (III) as a dopant material. The structures of compounds 2-7, BH1, and 5Cz-TRZ are as follows: 、 、 ； The structure of the boron-containing organic compound having the structure shown in formula (III) is as follows: (III) Among them, R1~R 14 Selected from any one of hydrogen atoms and unsubstituted C1-C20 alkyl groups; M is , .

2. The light-emitting device according to claim 1, characterized in that, The C1 to C20 alkyl groups are selected from any one of the following groups: Methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl.

3. The light-emitting device according to claim 1, characterized in that, R2, R5, R 10 R 13 For tert-butyl, R1, R 3-4 R 6-9 R 11-12 R 14 It is a hydrogen atom.

4. The light-emitting device according to claim 1, characterized in that, The boron-containing organic compound is selected from any one of the following: 。

Images