A monoboron organic compound as an OLED doping material and an organic electroluminescent device containing the same

Abstract

The present invention discloses a monoboron organic compound as an OLED doping material and an organic electroluminescent device containing the same, belonging to the field of semiconductor technology. The present invention provides a compound having a structure as shown in general formula (1). The compound of the present invention introduces a substituent group at a specific position of a boron-nitrogen fused ring parent nucleus and limits the spatial position of the compound to a specific angle of twist, so that the compound has a narrow half-peak width, a high fluorescence quantum yield, a relatively high radiation transition rate, and suitable HOMO and LUMO energy levels. The compound can be used as a green light doping material for the light-emitting layer of an organic electroluminescent device, thereby improving the luminescent color purity and lifespan of the device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, in particular to a monoboron organic compound as an OLED doping material and an organic electroluminescent device containing the same. Background Art

[0002] Traditional fluorescent doping materials, limited by early technology, can only utilize the 25% of singlet excitons formed by electrical excitation to emit light. This results in low internal quantum efficiency (maximum 25%) and external quantum efficiency generally below 5%, significantly lagging behind the efficiency of phosphorescent devices. Phosphorescent materials, due to the strong spin-orbit coupling at the heavy atom center that enhances intersystem crossing, can effectively utilize singlet and triplet excitons formed by electrical excitation to emit light, achieving a device internal quantum efficiency of 100%. However, the high cost of most phosphorescent materials, poor material stability, low color purity, and severe device efficiency roll-off have limited their application in OLEDs.

[0003] With the advent of the 5G era, higher requirements are being placed on color rendering standards. In addition to being efficient and stable, luminescent materials also need to have a narrower half-width to improve the color purity of the device's luminescent color. Fluorescent doping materials can achieve high fluorescence quantum and narrow half-width through molecular engineering. Blue fluorescent doping materials have achieved a phased breakthrough, and the half-width of boron-based materials can be reduced to below 30nm. However, research in the green light region, to which the human eye is more sensitive, has mainly focused on phosphorescent doping materials. However, their luminescent peak shape is difficult to narrow through simple methods. Therefore, to meet higher color rendering standards, it is of great significance to study efficient green fluorescent doping materials with narrow half-width.

[0004] In addition, TADF-sensitized fluorescence technology (TSF) combines TADF materials with fluorescent doping materials, using TADF materials as exciton-sensitizing media to convert triplet excitons formed by electrical excitation into singlet excitons, and transfers energy to fluorescent doping materials through long-range energy transfer of singlet excitons, which can also achieve 100% device quantum efficiency. This technology can make up for the shortcomings of insufficient exciton utilization of fluorescent doping materials, and effectively give play to the characteristics of high fluorescence quantum yield, high device stability, high color purity and low price of fluorescent doping materials, and has broad prospects in OLEDs applications.

[0005] Boron compounds with resonant structures are more likely to achieve narrow half-width luminescence. Such materials are used in TADF-sensitized fluorescence technology to achieve the preparation of devices with high efficiency and narrow half-width emission. For example, CN 107507921 A and CN110492006 A disclose a TADF material with a difference between the lowest singlet state and the lowest triplet state energy level of less than or equal to 0.2eV as the main body, and a boron-containing material as the doping luminescent layer combination technology; CN110492005A and CN 110492009 A disclose a luminescent layer combination scheme with an exciplex as the main body and a boron-containing material as the doping; both can achieve efficiency comparable to phosphorescence and a relatively narrow half-width. Therefore, the development of TADF-sensitized fluorescence technology based on narrow half-width boron-containing luminescent materials has unique advantages and strong potential in terms of BT.2020 display indicators. Summary of the Invention

[0006] In response to the above-mentioned problems existing in the prior art, the applicant of the present invention provides a monoboron organic compound as an OLED doping material. The compound of the present invention introduces a substituent group at a specific position of a boron-nitrogen fused ring parent nucleus and limits the spatial position of the compound to a specific angle of twist, so that the compound has a narrow half-width, high fluorescence quantum yield, a high radiation transition rate, and suitable HOMO and LUMO energy levels. It can be used as a green light doping material for the light-emitting layer of an organic electroluminescent device, thereby improving the luminous color purity and life of the device.

[0007] The technical solution of the present invention is as follows: a monoboron organic compound as an OLED doping material, the structure of the monoboron organic compound is shown in general formula (1):

[0008]

[0009] In the general formula (1), R1-R3 are independently cyano, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 cycloalkyl, substituted amino, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl;

[0010] X1-X3 are independently represented by C-R4; R4 is the same or different each time and represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C30 Heteroaryl, substituted or unsubstituted C3-C 30 The keto group;

[0011] The connection mode of R4 and general formula (1) is single bond substitution or cyclic connection;

[0012] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0013] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms;

[0014] The angle θ between the plane α where X1, X2 and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 10 degrees to 40 degrees.

[0015] The present invention also provides an organic electroluminescent device comprising a first electrode, a second electrode, and an organic light-emitting functional layer therebetween. The organic light-emitting functional layer comprises a light-emitting layer containing the monoboron organic compound.

[0016] The beneficial technical effects of the present invention are:

[0017] (1) The compounds of the present invention are applied to OLED devices and can be used as doping materials for light-emitting layer materials. They can emit green fluorescence under the action of an electric field and can be applied to OLED lighting or OLED display fields.

[0018] (2) The compound of the present invention has a high fluorescence quantum efficiency as a doping material, and the fluorescence quantum efficiency of the material is close to 100%;

[0019] (3) The compound of the present invention is used as a doping material, and the TADF sensitizer is introduced as a second host, which can effectively improve the device efficiency;

[0020] (4) The spectral FWHM of the compound of the present invention is relatively narrow, which can effectively improve the color gamut of the device and enhance the luminous efficiency of the device;

[0021] (5) The vapor deposition decomposition temperature of the compound of the present invention is relatively high, which can inhibit the vapor deposition decomposition of the material and effectively improve the life of the device.

[0022] (6) The radiation transition rate of the compound of the present invention is relatively high, which can effectively improve the life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1This is a schematic diagram of the structure of an OLED device in which the materials listed in the present invention are applied;

[0024] Among them, 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode layer. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The following will further illustrate the present invention with reference to the accompanying drawings and specific embodiments, but it is not intended to limit the present invention.

[0026] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital of a molecule, and LUMO means the lowest unoccupied molecular orbital of a molecule. In addition, in the present invention, HOMO and LUMO energy levels are expressed in absolute values, and comparison between energy levels also refers to comparison of their absolute values. Those skilled in the art will appreciate that the larger the absolute value of an energy level, the lower the energy of that energy level.

[0027] In the drawings, the dimensions of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on the other layer or substrate, or intervening layers may be present. Furthermore, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or one or more intervening layers may be present. Like reference numerals refer to like elements throughout.

[0028] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms such as "upper," "lower," "top," and "bottom" that indicate orientation refer only to a particular state and do not imply that the structure can exist only in the described orientation. Conversely, if the structure can be repositioned, such as inverted, the orientation of the structure will change accordingly. Specifically, in the present invention, the "bottom" or "lower" side of an electrode refers to the side of the electrode closest to the substrate during fabrication, while the opposite side, farther from the substrate, is the "top" or "upper" side.

[0029] In the present invention, substituted or unsubstituted C6-C 30 Aryl and / or substituted or unsubstituted C3-C 30Heteroaryl refers to substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted tetraphenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted p-terphenyl, substituted or unsubstituted m-terphenyl, substituted or unsubstituted substituted or unsubstituted triphenylene, substituted or unsubstituted perylene, substituted or unsubstituted indenyl, substituted or unsubstituted furyl, substituted or unsubstituted thienyl, substituted or unsubstituted pyrrolyl, substituted or unsubstituted pyrazolyl, substituted or unsubstituted imidazolyl, substituted or unsubstituted triazolyl, substituted or unsubstituted oxazolyl, substituted or unsubstituted thiazolyl, substituted or unsubstituted oxadiazolyl, substituted or unsubstituted thiadiazolyl, substituted or unsubstituted pyridinyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted triazinyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted unsubstituted benzimidazolyl, substituted or unsubstituted indolyl, substituted or unsubstituted quinolyl, substituted or unsubstituted isoquinolyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted quinoxalinyl, substituted or unsubstituted naphthyridinyl, substituted or unsubstituted benzoxazinyl, substituted or unsubstituted benzothiazinyl, substituted or unsubstituted acridinyl, substituted or unsubstituted phenanthrazinyl, substituted or unsubstituted phenathiazinyl, substituted or unsubstituted phenoxazinyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted carbazolyl, combinations thereof, or fused rings of combinations thereof, but are not limited thereto.

[0030] The C1-C of the present invention 10 Chain alkyl groups (including straight-chain alkyl groups and branched-chain alkyl groups) refer to methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, sec-butyl, neopentyl, n-pentyl, isopentyl, octyl, heptyl, n-decyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1-butylpentyl, etc., but are not limited thereto.

[0031] The halogen atom mentioned in the present invention refers to a chlorine atom, a fluorine atom or a bromine atom, but is not limited thereto.

[0032] The C3-C 10 A cycloalkyl group refers to a monovalent monocyclic saturated hydrocarbon group containing 3 to 10 carbon atoms as ring atoms. In this article, a C4-C9 cycloalkyl group is preferably used, a C5-C8 cycloalkyl group is more preferably used, and a C5-C7 cycloalkyl group is particularly preferably used. Non-limiting examples thereof may include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcyclohexyl, adamantyl, and cycloheptyl.

[0033] Monoboron organic compound represented by general formula (1):

[0034]

[0035] In the general formula (1), R1-R3 are independently cyano, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 cycloalkyl, substituted amino, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl;

[0036] X1-X3 are independently represented by C-R4; R4 is the same or different each time and represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C3-C 30 The keto group;

[0037] The connection mode of R4 and general formula (1) is single bond substitution or cyclic connection;

[0038] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0039] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms;

[0040] The angle θ between the plane α where X1, X2 and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 10 degrees to 40 degrees.

[0041] Preferably, the angle θ between the plane α where X1, X2, and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 20 degrees to 35 degrees, more preferably in the range of 25 degrees to 30 degrees.

[0042] In a preferred embodiment, the structure of the monoboron organic compound is as shown in any one of the general formulas (2) to (5):

[0043]

[0044] In general formula (2) to general formula (5), R1 to R3 are independently deuterium atoms, cyano groups, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 cycloalkyl, substituted amino, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl;

[0045] Each occurrence of Z is independently represented by C-R5; each occurrence of R5 is the same or different and represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl;

[0046] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0047] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms.

[0048] In a preferred embodiment, the structure of the monoboron organic compound is shown in the general formula (6):

[0049]

[0050] In the general formula (6), R1-R3 are independently deuterium atoms, cyano groups, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 cycloalkyl, substituted amino, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl;

[0051] R4 represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted C6-C 30aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C3-C 30 The keto group;

[0052] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0053] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms.

[0054] In a preferred embodiment, R1-R3 are independently represented by a deuterium atom, a cyano group, an adamantyl group, a methyl group, a trifluoromethyl group, an ethyl group, an isopropyl group, an isobutyl group, a tert-butyl group, a cyclopentyl group, a methyl-substituted cyclopentyl group, a cyclohexyl group, a phenyl group, a deuterated phenyl group, a biphenyl group, a deuterated biphenyl group, a terphenyl group, a diphenyl ether group, a methyl-substituted diphenyl ether group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyridyl group, a phenyl-substituted pyridyl group, a quinolyl group, a furyl group, a thienyl group, a benzofuranyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazole group, phenyl, N-phenylcarbazolyl, 9,9-dimethylfluorenyl, phenyl-substituted amino, tert-butylphenyl-substituted amino, tert-butyl-substituted dibenzofuranyl, methyl-substituted phenyl, ethyl-substituted phenyl, isopropyl-substituted phenyl, tert-butyl-substituted phenyl, methyl-substituted biphenyl, ethyl-substituted biphenyl, isopropyl-substituted biphenyl, tert-butyl-substituted biphenyl, tert-butyl-substituted phenyl, tert-butyl-substituted phenyl, xanthone, phenyl-substituted triazinyl, phenyl-substituted boryl, methoxy, tert-butoxy;

[0055] The R4 is represented by H, a deuterium atom, a cyano group, an adamantyl group, a methyl group, a trifluoromethyl group, an ethyl group, an isopropyl group, an isobutyl group, a tert-butyl group, a cyclopentyl group, a methyl-substituted cyclopentyl group, a cyclohexyl group, a phenyl group, a deuterated phenyl group, a phenylbenzofuran pyridine group, a biphenyl group, a deuterated biphenyl group, a terphenyl group, a diphenyl ether group, a methyl-substituted diphenyl ether group, a benzophenone group, a xanthone group, a naphthyl group, an anthracenyl group, a phenanthryl group, an indenyl group, a pyridazinyl group, a pyrazinyl group, a pyridyl group, a phenyl-substituted pyridyl group, a pyrimidinyl group, a phenyl-substituted pyrimidinyl group, a fluoranthenyl group, a dihydroacenaphthenyl group, a quinolyl group, an isoquinoline group, a phenylisoquinolyl group, a furyl group, a phenanthridinyl group, a thienyl group, a benzofuranyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a phenylbenzimidazolyl group, a benzodioxin group, a phenylphenanthridinyl group, Benzofuranopyrimidinyl, N-phenylcarbazolyl, indolocarbazole, 9,9-dimethylfluorenyl, spirofluorenyl, phenyl-substituted amino, tert-butylphenyl-substituted amino, tert-butyl-substituted dibenzofuranyl, methyl-substituted phenyl, ethyl-substituted phenyl, isopropyl-substituted phenyl, tert-butyl-substituted phenyl, methyl-substituted biphenyl, ethyl-substituted biphenyl, isopropyl-substituted biphenyl, tert-butyl-substituted biphenyl, phenyl-substituted tert-butyl, xanthone, phenyl-substituted triazinyl, dibenzofuranyl-substituted triazinyl, carbazolyl-substituted triazinyl, dibenzofuran-phenyl-triazinyl, indolocarbazole-phenyl-triazinyl, methoxy, tert-butoxy; the connection mode of R4 with the general formula (1) is single bond substitution or cyclic connection.

[0056] In a preferred embodiment, R5 is H, a deuterium atom, a cyano group, an adamantyl group, a methyl group, a trifluoromethyl group, an ethyl group, an isopropyl group, an isobutyl group, a tert-butyl group, a cyclopentyl group, a methyl-substituted cyclopentyl group, a cyclohexyl group, a phenyl group, a deuterated phenyl group, a biphenyl group, a deuterated biphenyl group, a terphenyl group, a diphenyl ether group, a methyl-substituted diphenyl ether group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyridyl group, a phenyl-substituted pyridyl group, a pyrimidyl group, a phenyl-substituted pyrimidyl group, a quinolyl group, a furyl group, a thienyl group, a benzofuranyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbofuranyl group, a thiophenyl group, a benzo ... oxazolyl, N-phenylcarbazolyl, 9,9-dimethylfluorenyl, spirofluorenyl, phenyl-substituted amino, tert-butylphenyl-substituted amino, tert-butyl-substituted dibenzofuranyl, methyl-substituted phenyl, ethyl-substituted phenyl, isopropyl-substituted phenyl, tert-butyl-substituted phenyl, methyl-substituted biphenyl, ethyl-substituted biphenyl, isopropyl-substituted biphenyl, tert-butyl-substituted biphenyl, phenyl-substituted tert-butyl, xanthone, phenyl-substituted triazinyl, phenyl-substituted boryl, methoxy, tert-butoxy.

[0057] In a preferred embodiment, R1 and R2 are independently represented by methyl, isopropyl, tert-butyl or phenyl; R3 is represented by phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano.

[0058] In a preferred embodiment, R1 and R2 are identically represented by methyl, isopropyl, tert-butyl or phenyl; and R3 is represented by phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano.

[0059] In a preferred embodiment, R1 and R2 are identical and represent tert-butyl; R3 is phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl, or cyano.

[0060] In a preferred embodiment, R1 and R2 are independently methyl, isopropyl, tert-butyl or phenyl, R3 is phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano, and R4 is phenyl or tert-butyl-substituted phenyl.

[0061] In a preferred embodiment, the structure of the monoboron organic compound is shown in the general formula (7):

[0062]

[0063] In the general formula (7), X1-X3 are independently represented by C-R4; R4, which is the same or different each time, is represented by H, a deuterium atom, a cyano group, a substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C3-C 30 The keto group;

[0064] The connection between R4 and the general formula (7) is a single bond substitution or a ring connection;

[0065] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0066] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms;

[0067] The angle θ between the plane α where X1, X2 and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 10 degrees to 40 degrees.

[0068] In a preferred embodiment, the structure of the monoboron organic compound is shown in the general formula (8):

[0069]

[0070] In the general formula (8), each occurrence of R4, which is the same or different, represents H, a deuterium atom, a cyano group, a substituted or unsubstituted C1-C 10 chain alkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C3-C 30 The keto group;

[0071] The connection between R4 and the general formula (8) is a single bond substitution;

[0072] The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Chain alkyl, C3~C 10 Cycloalkyl, C6~C 30 Aryl, C2~C 30 Any of heteroaryl groups;

[0073] The heteroatoms in the heteroaryl group are optionally selected from one or more of oxygen, sulfur or nitrogen atoms.

[0074] In a preferred embodiment, the specific structural formula of the monoboron organic compound is any one of the following structures:

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086] organic electroluminescent devices

[0087] The present invention provides an organic electroluminescent device comprising a first electrode, a second electrode, and an organic light-emitting functional layer therebetween. The organic light-emitting functional layer comprises a light-emitting layer containing a monoboron organic compound of general formula (1).

[0088] In a preferred embodiment of the present invention, the light-emitting layer comprises a host material and a dopant material, and the dopant material comprises a monoboron organic compound represented by the general formula (1).

[0089] In a preferred embodiment of the present invention, the light-emitting layer comprises a first host material, a second host material and a doping material, at least one of the first host material and the second host material is a TADF material, and the doping material is a monoboron organic compound described in general formula (1).

[0090] In a preferred embodiment of the present invention, an organic electroluminescent device is provided, which includes a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode layer, wherein the anode is above the substrate, the hole injection layer is above the anode, the hole transport layer is above the hole injection layer, the electron blocking layer is above the hole transport layer, the light-emitting layer is above the hole transport layer, the electron transport layer is above the light-emitting layer, the electron injection layer is above the electron transport layer, and the cathode layer is above the electron injection layer.

[0091] Figure 1 Schematic diagram of the structure of the compound of the present invention applied to an OLED device, wherein 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode layer.

[0092] As the substrate for the organic electroluminescent device of the present invention, any substrate commonly used for organic electroluminescent devices can be used. Examples include transparent substrates such as glass or transparent plastic substrates; opaque substrates such as silicon substrates; and flexible PI film substrates. Different substrates have varying mechanical strength, thermal stability, transparency, surface smoothness, and water resistance. Depending on the properties of the substrate, its use varies. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0093] A first electrode is formed on a substrate, and the first electrode and the second electrode may be opposite to each other. The first electrode may be an anode. The first electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode is a transmissive electrode, it may be formed using a transparent metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO). When the first electrode is a semi-transmissive electrode or a reflective electrode, it may include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a metal mixture. The thickness of the first electrode layer depends on the material used, and is typically 50-500 nm, preferably 70-300 nm, and more preferably 100-200 nm.

[0094] The organic functional material layer disposed between the first electrode and the second electrode includes, from bottom to top, a hole transport region, a light emitting layer and an electron transport region.

[0095] Herein, the hole transport region constituting the organic electroluminescent device can be exemplified by a hole injection layer, a hole transport layer, an electron blocking layer, and the like.

[0096] As materials for the hole injection layer, the hole transport layer, and the electron blocking layer, any material can be selected from known materials used in OLED devices.

[0097] Examples of the above materials include phthalocyanine derivatives, triazole derivatives, triarylmethane derivatives, triarylamine derivatives, oxazole derivatives, oxadiazole derivatives, hydrazone derivatives, stilbene derivatives, pyridinoline derivatives, polysilane derivatives, imidazole derivatives, phenylenediamine derivatives, amino-substituted quilone derivatives, styrylanthracene derivatives, styrylamine derivatives and other styrene compounds, fluorene derivatives, spirofluorene derivatives, silazane derivatives, aniline copolymers, porphyrin compounds, carbazole derivatives, polyarylalkane derivatives, polyphenylene vinyl and its derivatives, polythiophene and its derivatives, poly-N-vinylcarbazole derivatives, thiophene oligomers and other conductive polymer oligomers, aromatic tertiary amine compounds, styrene amination compounds, compounds, triamines, tetraamines, benzidines, propargyl diamine derivatives, p-phenylenediamine derivatives, m-phenylenediamine derivatives, 1,1'-bis(4-diarylaminophenyl)cyclohexane, 4,4'-bis(diarylamino)biphenyls, bis[4-(diarylamino)phenyl]methanes, 4,4'-bis(diarylamino)terphenyls, 4,4'-bis(diarylamino)quaterphenyls, 4,4'-bis(diarylamino)diphenyl ethers, 4,4'-bis(diarylamino)diphenylsulfanes, bis[4-(diarylamino)phenyl]dimethylmethanes, bis[4-(diarylamino)phenyl]-bis(trifluoromethyl)methanes, or 2,2-diphenylethylene compounds.

[0098] Furthermore, depending on the device configuration requirements, the hole transport film layer between the hole transport auxiliary layer and the hole injection layer of the organic electroluminescent device can be a single film layer or a stacked structure of multiple hole transport materials. In this article, the thickness of the various hole carrier conductive film layers with different functions described above is not particularly limited.

[0099] The hole injection layer contains a host organic material that can conduct holes, and also contains a P-type dopant material with a deep HOMO energy level (the corresponding LUMO energy level will also be very deep). Based on empirical summary, in order to achieve smooth hole injection from the anode to the organic film layer, the HOMO energy level of the host organic material used in the anode interface buffer layer must have certain characteristics with the P-doped material. Only then can the charge transfer state between the host material and the dopant material be achieved, and ohmic contact between the buffer layer and the anode can be achieved, achieving efficient injection and conduction of holes from the electrode.

[0100] In view of the above empirical summary, for hole-type host materials with different HOMO energy levels, different P-doped materials need to be selected to match them in order to achieve ohmic contact at the interface and improve the hole injection effect.

[0101] Therefore, in one embodiment of the present invention, in order to better inject holes, the hole injection layer further includes a P-type dopant material with charge conductivity selected from the following: quinone derivatives, such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinodimethane (F4-TCNQ); or hexaazatriphenylene derivatives, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN); or cyclopropane derivatives, such as 4,4',4"-((1E,1'E,1"E)-cyclopropane-1,2,3-trimethylenetris(cyanoformylidene))tris(2,3,5,6-tetrafluorobenzyl); or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0102] In the hole injection layer of the present invention, the ratio of the hole transport material to the P-type doping material is 99:1-95:5, preferably 99:1-97:3, based on mass.

[0103] The thickness of the hole injection layer of the present invention may be 5-100 nm, preferably 5-50 nm, and more preferably 5-20 nm, but the thickness is not limited to this range.

[0104] The thickness of the hole transport layer of the present invention may be 5 to 200 nm, preferably 10 to 150 nm, and more preferably 20 to 100 nm, but the thickness is not limited to this range.

[0105] The thickness of the electron blocking layer of the present invention may be 1-20 nm, preferably 5-10 nm, but the thickness is not limited to this range.

[0106] After forming the hole injection layer, the hole transport layer and the electron blocking layer, a corresponding light emitting layer is formed on the electron blocking layer.

[0107] The light-emitting layer may include a host material and a dopant material. The host material may be a common green light host material in the art, and the dopant material may be a monoboron organic compound represented by the general formula (1) of the present invention.

[0108] In the light-emitting layer of the present invention, the ratio of the host material to the dopant material used is 99:1-70:30, preferably 99:1-85:15 and more preferably 97:3-87:13, based on mass.

[0109] The thickness of the light-emitting layer can be adjusted to optimize the luminous efficiency and driving voltage. The preferred thickness range is 5 nm to 50 nm, more preferably 10-50 nm, and more preferably 15-30 nm, but the thickness is not limited to this range.

[0110] In the present invention, the electron transport region may include, from bottom to top, a hole blocking layer, an electron transport layer, and an electron injection layer disposed on the light emitting layer, but is not limited thereto.

[0111] The hole blocking layer is a layer that blocks the holes injected from the anode from passing through the light-emitting layer and entering the cathode, thereby extending the life of the device and improving the performance of the device. The hole blocking layer of the present invention can be arranged on the light-emitting layer. As the hole blocking layer material of the organic electroluminescent device of the present invention, compounds with hole blocking effects known in the prior art can be used, for example, phenanthroline derivatives such as bathocuproine (called BCP), metal complexes of hydroxyquinoline derivatives such as aluminum (III) bis (2-methyl-8-quinolinol) -4-phenylphenolate (BAlq), various rare earth complexes, oxazole derivatives, triazole derivatives, triazine derivatives, 9,9'-(5-(6-([1,1'-biphenyl]-4-yl)-2-phenylpyrimidin-4-yl)-1,3-phenylene)bis(9H-carbazole) (CAS No.: 1345338-69-3 ) and other pyrimidine derivatives, etc. The thickness of the hole blocking layer of the present invention may be 2-200 nm, preferably 5-150 nm and more preferably 10-100 nm, but the thickness is not limited to this range.

[0112] The electron transport layer can be disposed on the light-emitting layer or (if present) the hole blocking layer. The electron transport layer material is a material that readily accepts electrons from the cathode and transfers the received electrons to the light-emitting layer. Preferably, the material has a high electron mobility. As the electron transport layer of the organic electroluminescent device of the present invention, electron transport layer materials for organic electroluminescent devices known in the prior art can be used, for example, metal complexes of hydroxyquinoline derivatives represented by Alq3, BAlq and Liq, various rare earth metal complexes, triazole derivatives, 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalene-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6) and other triazine derivatives, 2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS No.: 561064-11-7, commonly known as LG201) and other imidazole derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silicon-based compound derivatives, etc. The thickness of the electron transport layer of the present invention may be 10-80 nm, preferably 20-60 nm, and more preferably 25-45 nm, but the thickness is not limited to this range.

[0113] The electron injection layer may be provided above the electron transport layer. The electron injection layer material is generally preferably a material having a low work function so that electrons are easily injected into the organic functional material layer. As the electron injection layer material of the organic electroluminescent device of the present invention, the electron injection layer materials for organic electroluminescent devices known in the prior art can be used, for example, lithium; lithium salts such as 8-hydroxyquinoline lithium, lithium fluoride, lithium carbonate or lithium azide; or cesium salts such as cesium fluoride, cesium carbonate or cesium azide. The thickness of the electron injection layer of the present invention may be 0.1-5 nm, preferably 0.5-3 nm and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0114] The second electrode may be disposed above the electron transport region. The second electrode may be a cathode. The second electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the second electrode is a transmissive electrode, the second electrode may include, for example, Li, Yb, Ca, LiF / Ca, LiF / Al, Al, Mg, BaF, Ba, Ag, or a compound or mixture thereof; when the second electrode is a semi-transmissive electrode or a reflective electrode, the second electrode may include, but is not limited to, Ag, Mg, Yb, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture thereof. The thickness of the cathode depends on the material used and is typically 10-50 nm, preferably 15-20 nm.

[0115] The organic electroluminescent device of the present invention may further include an encapsulation structure. The encapsulation structure may be a protective structure that prevents foreign substances, such as moisture and oxygen, from entering the organic layer of the organic electroluminescent device. The encapsulation structure may be, for example, a can, such as a glass or metal can, or a thin film covering the entire surface of the organic layer.

[0116] Method for preparing organic electroluminescent device

[0117] The present invention also relates to a method for preparing the above-mentioned organic electroluminescent device, which comprises sequentially laminating a first electrode, a plurality of organic thin film layers, and a second electrode on a substrate. The plurality of organic thin film layers is formed by sequentially laminating a hole transport region, a light-emitting layer, and an electron transport region on the first electrode from bottom to top. The hole transport region is formed by sequentially laminating a hole injection layer, a hole transport layer, and an electron blocking layer on the first electrode from bottom to top. The electron transport region is formed by sequentially laminating a hole blocking layer, an electron transport layer, and an electron injection layer on the light-emitting layer from bottom to top. Optionally, a CPL layer may be laminated on the second electrode to improve the light extraction efficiency of the organic electroluminescent device.

[0118] Regarding lamination, vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing or LITI method can be used, but are not limited thereto. Vacuum evaporation means heating and coating a material on a substrate in a vacuum environment.

[0119] In the present invention, it is preferred to use a vacuum evaporation method to form the various layers, wherein the layers can be formed at a temperature of about 100-500° C. and a temperature of about 10- 8 -10- 2 Torr vacuum and about The vacuum evaporation is carried out at a rate of 10- 6 -10- 2 Torr, more preferably 10- 5 -10- 3 Torr. The rate is about More preferably, about

[0120] In addition, it should be noted that the materials used to form each layer described in the present invention can be formed into a film alone and used as a single layer, or can be mixed with other materials to form a film and used as a single layer. It can also be a stacked structure between layers formed into films alone, a stacked structure between layers formed into films after mixing, or a stacked structure between layers formed into films alone and layers formed into films after mixing.

[0121] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0122] The raw materials involved in the synthesis examples of the present invention can be purchased from the market or prepared by conventional preparation methods in the art;

[0123] Example 1 Synthesis of Compound 1:

[0124]

[0125] (1) Preparation of intermediate a-1:

[0126] In a three-necked flask, under argon protection, 0.893 mmol of raw material A-1, 2.239 mmol of methylboronic acid, 3.58 mmol of potassium phosphate, 0.045 mmol of Pd(OAc)2, and 0.091 mmol of Mephos were added, followed by the addition of 10 mL of a toluene / water solution (toluene: water = 3:1). The mixture was heated to 100°C and reacted for 48 hours. The mixture was naturally cooled to room temperature, filtered, and the filtrate was subjected to vacuum rotary evaporation. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:1) to obtain intermediate a-1. LC-MS: Measured value: 294.05 ([M+H] + ), theoretical value: 293.21.

[0127]

[0128] (2) Preparation of intermediate b-1:

[0129] Under nitrogen protection, 0.90 mmol of raw material B-1, 2.70 mmol of intermediate a-1, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask and then heated to 110°C. After stirring for 3 hours, the reaction mixture was cooled to room temperature and poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE: DCM = 5:1) to obtain intermediate b-1. LC-MS: Measured value: 661.26 ([M+H] + ), theoretical value: 660.44.

[0130]

[0131] (3) Preparation of Compound 1:

[0132] In a three-necked flask, under nitrogen, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-1 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 20 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of pH 6 sodium phosphate buffer was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 1.

[0133] Example 2 Synthesis of Compound 4:

[0134]

[0135] (1) Preparation of intermediate a-2:

[0136] In a three-necked flask, under argon protection, 0.893 mmol of raw material A-1, 2.239 mmol of tert-butylboronic acid, 3.58 mmol of potassium phosphate, 0.045 mmol of Pd(OAc)2, and 0.091 mmol of Mephos were added, followed by the addition of 10 mL of a toluene / water solution (toluene: water = 3:1). The mixture was heated to 100°C and reacted for 49 hours. The mixture was naturally cooled to room temperature, filtered, and the filtrate was subjected to vacuum rotary evaporation. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:1) to obtain intermediate a-2. LC-MS: Measured value: 336.18 ([M+H] + ), theoretical value: 335.26.

[0137]

[0138] (2) Preparation of intermediate b-2:

[0139] Under nitrogen protection, 0.90 mmol of raw material B-1, 2.70 mmol of intermediate a-2, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask and then heated to 110°C. After stirring for 4 hours, the reaction mixture was cooled to room temperature and poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE: DCM = 5:1) to obtain intermediate b-2. LC-MS: Measured value: 745.48 ([M+H] + ), theoretical value: 744.54.

[0140]

[0141] (3) Preparation of compound 4:

[0142] In a three-necked flask, under nitrogen, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-2 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 22 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of pH 6 sodium phosphate buffer was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 4.

[0143] Example 3 Synthesis of Compound 20:

[0144]

[0145] (1) Preparation of intermediate a-3:

[0146] Under nitrogen protection, 10.0 mmol of raw material A-2 and 36.0 mmol of raw material C-1 were added to a three-necked flask and dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol). Then, 0.1 mmol of Pd(PPh3)4 and 15 mL of a 3 mol / L aqueous solution of K2CO3 were added and heated under reflux for 12 hours. A sample was taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a celite pad, rinsed with chloroform, and the resulting filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain intermediate a-3. LC-MS: Measured value: 396.20 ([M+H] + ), theoretical value: 395.17.

[0147]

[0148] (2) Preparation of intermediate b-3:

[0149] Under nitrogen protection, 0.90 mmol of raw material B-1, 2.70 mmol of intermediate a-3, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask and then heated to 110°C. After stirring for 6 hours, the reaction mixture was cooled to room temperature and poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE: DCM = 5:1) to obtain intermediate b-3. LC-MS: Measured value: 865.19 ([M+H] + ), theoretical value: 864.35.

[0150]

[0151] (3) Preparation of Compound 20:

[0152] In a three-necked flask, under nitrogen, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-3 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 23 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of pH 6 sodium phosphate buffer was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 20.

[0153] Example 4 Synthesis of Compound 64:

[0154]

[0155] (1) Preparation of intermediate b-4:

[0156] Under nitrogen protection, 0.90 mmol of raw material B-2, 2.70 mmol of intermediate a-1, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask and then heated to 110°C. After stirring for 3 hours, the reaction mixture was cooled to room temperature and poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE: DCM = 5:1) to obtain intermediate b-4. LC-MS: Measured value: 739.28 ([M+H] + ), theoretical value: 738.35.

[0157]

[0158] (2) Preparation of intermediate c-1:

[0159] In a three-necked flask, under nitrogen protection, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-4 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 20 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of sodium phosphate buffer solution with a pH of 6 was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 ml, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain intermediate c-1. LC-MS: Measured value: 747.05 ([M+H] + ), theoretical value: 746.34.

[0160]

[0161] (3) Preparation of Compound 64:

[0162] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-2 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh)₃₄ and 20 mL of a 3 mol / L aqueous solution of K₂CO₃ were heated under reflux for 18 hours. A sample was taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain the target compound 64.

[0163] Example 5 Synthesis of Compound 75:

[0164]

[0165] (1) Preparation of Compound 75:

[0166] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-3 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh3)4, 20 mL of a 3 mol / L aqueous solution of K2CO3, and heating under reflux for 25 hours. Samples were taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain the target compound 75.

[0167] Example 6 Synthesis of Compound 98:

[0168]

[0169] (1) Preparation of Compound 98:

[0170] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-4 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh)₃₄ and 20 mL of a 3 mol / L aqueous solution of K₂CO₃ were heated under reflux for 20 hours. A sample was taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to yield the target compound 98.

[0171] Example 7 Synthesis of Compound 110:

[0172]

[0173] (1) Preparation of intermediate b-5:

[0174] Under nitrogen protection, 0.90 mmol of raw material B-3, 2.70 mmol of intermediate a-1, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask and then heated to 110°C. After stirring for 4 hours, the reaction mixture was cooled to room temperature and poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE: DCM = 5:1) to obtain intermediate b-5. LC-MS: Measured value: 711.25 ([M+H] + ), theoretical value: 710.46.

[0175]

[0176] (2) Preparation of Compound 110:

[0177] In a three-necked flask, under nitrogen, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-5 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 21 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of pH 6 sodium phosphate buffer was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 110.

[0178] Example 8 Synthesis of Compound 114:

[0179]

[0180] (1) Preparation of intermediate b-6:

[0181] Under nitrogen protection, 10.0mmol raw material B-4, 24.0mmol intermediate a-1, and 150mL toluene were added to a three-necked flask and stirred to mix. Then 0.05mmol Pd2(dba)3, 0.05mmol P(t-Bu)3, and 30.0mmol sodium tert-butoxide were added and refluxed at 105°C for 24h. The sample point plate was taken to confirm that the reaction was complete. After cooling to room temperature, the reaction mixture was filtered through a celite pad, rinsed with chloroform, and the resulting filtrate was evaporated in vacuo. The obtained residue was purified by column chromatography on silica gel using hexane / toluene as eluent to obtain intermediate b-6. LC-MS: Measured value: 751.37 ([M+H] + ), theoretical value: 750.45.

[0182]

[0183] (2) Preparation of Compound 114:

[0184] In a three-necked flask, under nitrogen, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate b-6 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180°C for 19 hours, the reaction mixture was diluted with dichloromethane (50 mL) and 100 mL of pH 6 sodium phosphate buffer was added at 0°C. The aqueous layer was separated and extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 114.

[0185] Example 9 Synthesis of Compound 124:

[0186]

[0187] (1) Preparation of Compound 124:

[0188] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-5 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh)₃₄ and 20 mL of a 3 mol / L aqueous solution of K₂CO₃ were heated under reflux for 24 hours. A sample was taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain the target compound 124.

[0189] Example 10 Synthesis of Compound 131:

[0190]

[0191] (1) Preparation of Compound 131:

[0192] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-6 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh3)4, 20 mL of a 3 mol / L aqueous solution of K2CO3, and heating under reflux for 16 hours. Samples were taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain the target compound 131.

[0193] Example 11 Synthesis of Compound 140:

[0194]

[0195] (1) Preparation of Compound 140:

[0196] Under nitrogen protection, 10.0 mmol of intermediate c-1 and 12.0 mmol of raw material C-7 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol Pd(PPh)₃₄ and 20 mL of a 3 mol / L aqueous solution of K₂CO₃ were heated under reflux for 18 hours. A sample was taken to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a pad of celite, rinsed with chloroform, and the filtrate was evaporated in vacuo. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain the target compound 140.

[0197] The structural characteristics of the compounds obtained in each example are shown in Table 1

[0198] Table 1

[0199]

[0200]

[0201] In the present invention, the angle θ between the plane α where X1, X2, and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located in the structure of general formula (1) is obtained by quantum chemical calculation methods. First, each structure is geometrically optimized using Gaussian16, with the calculation level being b3lyp / 6-31G(d). After the molecular optimization is completed, the coordinates of X1, X2, and X3, the B atom, and the two N atoms are retrieved, and the normal vector is calculated using the coordinates of any three atoms in the plane. The angle between the normal vectors is then calculated, which is the angle θ between the two planes. The calculation results are shown in Table 2:

[0202] Table 2

[0203] Compound Angle θ (degrees) 1 27.0840 4 28.9093 20 23.9633 64 28.0722 75 26.4911 98 26.9411 110 33.7122 114 29.8219 124 28.2833 131 27.9964 140 28.0134 ref-1 3.5582 ref-2 18.4783

[0204] As can be seen from the data in Table 2 above, the compound represented by the general formula (1) of the present invention introduces a substituent group at a specific position of the parent nucleus, restricting the spatial position of the compound so that the angle θ between the plane α where X1, X2, and X3 are located in the compound structure and the plane β where the B atom and two N atoms are located in the parent nucleus is within the range of 20-35 degrees, suppressing the torsional vibration in the resonant boron-nitrogen framework structure, greatly enhancing the molecular rigidity, thereby significantly improving the radiation transition rate of the material, and thus improving the device life. When the angle θ between the plane α where X1, X2, and X3 are located in the compound structure and the plane β where the B atom and two N atoms are located in the parent nucleus is greater than 40 degrees, the molecule easily forms an intramolecular charge transfer state (CT state), thereby reducing the fluorescence quantum yield of the material and widening the half-peak width.

[0205] The compounds of the present invention can be used in light-emitting devices as doping materials for light-emitting layers. The physical and chemical properties of the compounds prepared in the above embodiments of the present invention were tested, and the test results are shown in Table 3:

[0206] Table 3

[0207]

[0208]

[0209] Note: Glass transition temperature (Tg) was determined by differential scanning calorimetry (DSC, DSC204F1 differential scanning calorimeter, NETZSCH, Germany) at a heating rate of 10°C / min. Thermogravimetric temperature (Td) was the temperature at which 1% weight loss occurred in a nitrogen atmosphere, measured on a Shimadzu TGA-50H thermogravimetric analyzer (Shimadzu, Japan) at a nitrogen flow rate of 20 mL / min. The highest occupied molecular orbital (HOMO) energy level was measured using an ionization energy measurement system (IPS-3) in a nitrogen atmosphere. Eg was measured using a dual-beam UV-visible spectrophotometer (TU-1901), where LUMO = HOMO + Eg. PLQY (fluorescence quantum yield) and FWHM (full width at half maximum) were measured in thin film form using a Horiba Fluorolog-3 series fluorescence spectrometer. τ (transient state) was measured in thin film form using a Horiba Fluorolog-3 series fluorescence spectrometer, where Kr (radiative transition rate) = 1 / τ.

[0210] As shown in Table 3, the compounds of the present invention exhibit high glass transition temperatures and decomposition temperatures. When used as dopants in the luminescent layer, they can inhibit crystallization and film phase separation; they can also inhibit decomposition at high brightness, thereby increasing the device's operating life. Furthermore, the compounds of the present invention possess suitable HOMO energy levels, making them suitable for doping in host materials. This helps suppress the generation of carrier traps, improves host-guest energy transfer efficiency, and thus enhances device luminescence efficiency.

[0211] The compound of the present invention has a high fluorescence quantum efficiency as a doping material, and the fluorescence quantum efficiency of the material is close to 100%; at the same time, the spectral FWHM of the material is narrow, which can effectively improve the color gamut of the device and improve the luminous efficiency of the device; finally, the evaporation decomposition temperature of the material is high, which can inhibit the evaporation decomposition of the material, and the radiation transition rate of the material is high, which can effectively improve the life of the device.

[0212] The following describes in detail the application effects of the OLED materials synthesized by the present invention in devices using device Examples 1-11 and Comparative Examples 1-2. The device fabrication processes for Device Examples 2-11 and Comparative Examples 1-2 are identical to those of Device Example 1, utilizing the same substrate and electrode materials, with the same electrode thickness. The only difference is the material used in the light-emitting layer. The layer structures and test results for each device example are shown in Tables 4 and 5, respectively.

[0213] Device Example 1

[0214] like Figure 1As shown, the transparent substrate layer 1 is a transparent PI film, and the ITO anode layer 2 (film thickness is 150nm) is washed, that is, washed with a detergent (Semiclean M-L20), washed with pure water, dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the transparent ITO. On the ITO anode layer 2 after the above washing, a vacuum evaporation device is used to evaporate HT-1 and HI-1 with a film thickness of 10nm as the hole injection layer 3, and the mass ratio of HT-1 and HI-1 is 97:3. Then, HT-1 with a thickness of 60nm is evaporated as the hole transport layer 4. Subsequently, EB-1 with a thickness of 30nm is evaporated as the electron blocking layer 5. After the above-mentioned electron blocking material is evaporated, the light-emitting layer 6 of the OLED light-emitting device is made, using CBP as the main material and compound 1 as the doping material. The mass ratio of CBP and compound 1 is 97:3, and the light-emitting layer thickness is 30nm. After the light-emitting layer 6, HB-1 was vacuum-deposited to a thickness of 5 nm. This layer served as the hole-blocking layer 7. After the hole-blocking layer 7, ET-1 and Liq were vacuum-deposited in a 1:1 weight ratio to form a 30 nm thick film. This served as the electron-transporting layer 8. On the electron-transporting layer 8, a 1 nm thick LiF layer was vacuum-deposited. This served as the electron-injection layer 9. On the electron-injection layer 9, an 80 nm thick Mg:Ag electrode layer was vacuum-deposited in a 1:9 weight ratio. This served as the cathode layer 10.

[0215] The following describes in detail the application effects of the OLED materials synthesized by the present invention in devices using device Examples 12-22 and Comparative Examples 3-4. The device fabrication processes for Device Examples 13-22 and Comparative Examples 3-4 are identical to those for Device Example 12, utilizing the same substrate and electrode materials, with the same electrode thickness. The only difference is the material used in the light-emitting layer. The layer structures and test results for each device example are shown in Tables 4 and 5, respectively.

[0216] Device Example 12

[0217] The transparent substrate layer 1 is a transparent PI film. The ITO anode layer 2 (film thickness 150nm) is washed, that is, washed with a detergent (Semiclean M-L20), washed with pure water, dried, and then washed with ultraviolet-ozone to remove organic residues on the transparent ITO surface. On the ITO anode layer 2 after the above washing, HT-1 and HI-1 are evaporated with a film thickness of 10nm as the hole injection layer 3 using a vacuum evaporation device. The mass ratio of HT-1 to HI-1 is 97:3. HT-1 is then evaporated with a thickness of 60nm as the hole transport layer 4. EB-1 is then evaporated with a thickness of 30nm as the electron blocking layer 5. After the above electron blocking material evaporation is completed, the light-emitting layer 6 of the OLED light-emitting device is prepared. CBP and DMAC-BP are used as the dual host materials, and compound 1 is used as the dopant material. The mass ratio of CBP, DMAC-BP and compound 1 is 67:30:3, and the light-emitting layer thickness is 30nm. After the light-emitting layer 6, HB-1 was vacuum-deposited to a thickness of 5 nm. This layer served as the hole-blocking layer 7. After the hole-blocking layer 7, ET-1 and Liq were vacuum-deposited in a 1:1 weight ratio to form a 30 nm thick film. This served as the electron-transporting layer 8. On the electron-transporting layer 8, a 1 nm thick LiF layer was vacuum-deposited. This served as the electron-injection layer 9. On the electron-injection layer 9, an 80 nm thick Mg:Ag electrode layer was vacuum-deposited in a 1:9 weight ratio. This served as the cathode layer 10.

[0218] The molecular structure formula of the relevant materials is shown below:

[0219]

[0220] After completing the OLED light-emitting device as described above, the anode and cathode were connected using a known drive circuit, and the device's current efficiency, external quantum efficiency, and lifetime were measured. Examples and comparative examples of devices prepared using the same method are shown in Table 4; the test results for the current efficiency, external quantum efficiency, and lifetime of the resulting devices are shown in Table 5.

[0221] Table 4

[0222]

[0223]

[0224] Table 5

[0225]

[0226] Note: Voltage, current efficiency, and luminescence peak were measured using an IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instrument Co., Ltd.); the lifespan test system was an EAS-62C OLED device lifespan tester from Japan System Giken Co., Ltd.; LT95 refers to the time it takes for the device's luminance to decay to 95%; all data are measured at 10 mA / cm 2 Next test.

[0227] It can be seen from the device data results in Table 5 that, compared with device comparison examples 1-4, the current efficiency, external quantum efficiency and device life of the organic light-emitting device of the present invention are greatly improved compared with OLED devices made of known materials.

[0228] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A monoboron organic compound as an OLED doping material, characterized in that: The structure of the monoboron organic compound is shown in general formula (1): In the general formula (1), R1-R3 are independently cyano, substituted or unsubstituted C1-C 10 a chain alkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group; X1-X3 are independently represented by C-R4; R4 is the same or different each time and represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 a chain alkyl group, a benzophenone group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted triazinyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted carbazolyl group; The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Any of the chain alkyl and phenyl groups; The angle θ between the plane α where X1, X2 and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 10 degrees to 40 degrees.

2. The monoboron organic compound according to claim 1, characterized in that The angle θ between the plane α where X1, X2, and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 20 degrees to 35 degrees.

3. The monoboron organic compound according to claim 1, characterized in that The angle θ between the plane α where X1, X2, and X3 are located and the plane β where the B atom and two N atoms in the parent nucleus are located is in the range of 25 degrees to 30 degrees.

4. A monoboron organic compound, characterized in that The structure of the monoboron organic compound is shown in any one of the general formulas (2) to (5): In general formula (2) to general formula (5), R1 to R3 are independently cyano, substituted or unsubstituted C1-C 10 a chain alkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group; Each occurrence of Z is independently represented by C-R5; each occurrence of R5 is the same or different and represents H, deuterium atom, cyano group, C1-C 10 Chain alkyl and phenyl groups; The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Any one of a chain alkyl group or a phenyl group.

5. The monoboron organic compound according to claim 1, characterized in that The structure of the monoboron organic compound is shown in general formula (6): In the general formula (6), R1-R3 are independently cyano, substituted or unsubstituted C1-C 10 a chain alkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group; R4 represents H, deuterium atom, cyano group, substituted or unsubstituted C1-C 10 a chain alkyl group, a benzophenone group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted triazinyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted carbazolyl group; The substituents of the "substituted or unsubstituted" groups are selected from deuterium atoms, halogen atoms, cyano groups, C1-C 10 Any one of a chain alkyl group or a phenyl group.

6. The monoboron organic compound according to claim 1, characterized in that Said R1-R3 are independently represented by cyano, methyl, trifluoromethyl, ethyl, isopropyl, isobutyl, tert-butyl, phenyl, deuterated phenyl, methyl-substituted phenyl, ethyl-substituted phenyl, isopropyl-substituted phenyl, tert-butyl-substituted phenyl; The R4 is represented by H, a deuterium atom, a cyano group, a methyl group, a trifluoromethyl group, an ethyl group, an isopropyl group, an isobutyl group, a tert-butyl group, a phenyl group, a deuterated phenyl group, a biphenyl group, a deuterated biphenyl group, a benzophenone group, a pyridyl group, a pyrimidinyl group, a benzofuranyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a carbazolyl group, an N-phenylcarbazolyl group, a methyl-substituted phenyl group, an ethyl-substituted phenyl group, an isopropyl-substituted phenyl group, a tert-butyl-substituted phenyl group, a methyl-substituted biphenyl group, an ethyl-substituted biphenyl group, an isopropyl-substituted biphenyl group, a tert-butyl-substituted biphenyl group, or a phenyl-substituted triazinyl group.

7. The monoboron organic compound according to claim 4, characterized in that The R5 is represented by H, a deuterium atom, a cyano group, a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a tert-butyl group, or a phenyl group.

8. The monoboron organic compound according to any one of claims 1 to 5, characterized in that Said R1 and R2 are independently represented by methyl, isopropyl, tert-butyl or phenyl; R3 is represented by phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano.

9. The monoboron organic compound according to any one of claims 1 to 5, characterized in that The R1 and R2 are identical and represent methyl, isopropyl, tert-butyl or phenyl; R3 is phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano.

10. The monoboron organic compound according to any one of claims 1 to 5, characterized in that: The R1 and R2 are the same and represent tert-butyl; R3 is phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl, or cyano.

11. The monoboron organic compound according to claim 5, characterized in that: The R1 and R2 are independently represented by methyl, isopropyl, tert-butyl or phenyl, R3 is represented by phenyl, methyl, isopropyl, tert-butyl, trifluoromethyl or cyano, and R4 is represented by phenyl or tert-butyl substituted phenyl.

12. A monoboron organic compound as an OLED doping material, characterized in that: The specific structural formula of the monoboron organic compound is any one of the following structures:

13. An organic electroluminescent device comprising a first electrode and a second electrode, and an organic light-emitting functional layer therebetween, wherein the organic light-emitting functional layer comprises a light-emitting layer, characterized in that: The light-emitting layer contains the monoboron organic compound according to any one of claims 1 to 12.

14. The organic electroluminescent device according to claim 13, characterized in that: The light-emitting layer comprises a host material and a doping material, wherein the doping material contains the monoboron organic compound according to any one of claims 1 to 12.

15. The organic light-emitting device according to claim 13, wherein the light-emitting layer comprises a first host material, a second host material and a dopant material, wherein: At least one of the first host material and the second host material is a TADF material, and the doping material is the monoboron organic compound according to any one of claims 1 to 12.

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