Organic compound for organic electroluminescent device, organic electroluminescent device

Abstract

The present invention provides a compound and its application. The compound has a structure shown in formula (1). When the compound of the present invention is used in an organic electroluminescent device, especially as a luminescent dye material, the device excitation voltage can be effectively reduced, the device luminescence efficiency can be improved, and the best effect can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, in particular to an organic compound and application thereof, and also to an organic electroluminescence device. Background Art

[0002] In recent years, optoelectronic devices based on organic materials have become increasingly popular. The inherent flexibility of organic materials makes them very suitable for manufacturing on flexible substrates. Beautiful and cool optoelectronic products can be designed and produced according to demand, gaining unparalleled advantages over inorganic materials. Examples of such organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic field-effect transistors, organic photovoltaic cells, organic sensors, etc. Among them, OLED has developed particularly rapidly and has achieved commercial success in the field of information display. OLED can provide highly saturated red, green, and blue colors. Full-color display devices made of OLEDs do not require additional backlight sources and have the advantages of brilliant colors, lightness, thinness, and softness.

[0003] The core of OLED devices is a thin film structure containing a variety of organic functional materials. Common functionalized organic materials include: hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, luminescent host materials and luminescent guest (dyes), etc. When power is turned on, electrons and holes are injected and transported to the luminescent area respectively and recombine there, thereby generating excitons and emitting light.

[0004] People have developed a variety of organic materials, combined with various unique device structures, which can improve carrier mobility, regulate carrier balance, break through electroluminescence efficiency, and delay device attenuation. For quantum mechanical reasons, common fluorescent luminescent bodies mainly use singlet excitons generated when electrons and voids combine to emit light, and are still widely used in various OLED products. Some metal complexes, such as iridium complexes, can simultaneously use triplet excitons and singlet excitons to emit light, and are called phosphorescent luminescent bodies. Their energy conversion efficiency can be increased by up to four times that of traditional fluorescent luminescent bodies. Thermally excited delayed fluorescence (TADF) technology promotes the transformation of triplet excitons to singlet excitons. Without the use of metal complexes, triplet excitons can still be effectively utilized to achieve higher luminescence efficiency. Thermally excited sensitized fluorescence (TASF) technology uses materials with TADF properties to sensitize luminescent bodies by energy transfer, which can also achieve higher luminescence efficiency. Especially in the field of blue luminescence, which has always been difficult to effectively improve luminescence efficiency, it has a very broad application prospect.

[0005] Under the condition of electrical excitation, organic electroluminescent devices will produce 25% singlet and 75% triplet excitons. Traditional fluorescent materials can only use 25% of singlet excitons due to spin prohibition, so the external quantum efficiency is limited to less than 5%. Almost all triplet excitons can only be lost in the form of heat. In order to improve the efficiency of organic electroluminescent devices, triplet excitons must be fully utilized.

[0006] To this end, researchers have proposed many methods, the most notable of which is the use of phosphorescent materials. Phosphorescent materials introduce heavy atoms and have a spin-orbit coupling effect, which can fully utilize 75% of triplet excitons and achieve 100% internal quantum efficiency. However, phosphorescent materials use rare heavy metals, which makes the materials expensive and not conducive to cost control. If fluorescent devices can make good use of triplet excitons, this problem can be solved well. Researchers have proposed a method to improve the efficiency of fluorescent devices by quenching triplet excitons to produce singlet excitons in fluorescent devices, but the maximum external quantum efficiency that this method can theoretically achieve is only 62.5%, which is much lower than that of phosphorescent materials. Therefore, it is very necessary to find new technologies to make full use of the triplet energy levels of fluorescent materials to improve the luminescence efficiency.

[0007] In the prior art, some thermally activated delayed fluorescent luminescent materials have been reported, which are used as fluorescent dopants, see patent document US20190181353 for details.

[0008]

[0009] However, as OLED products gradually enter the market, people have increasingly higher requirements for the performance of such products. The above-mentioned OLED materials and device structures cannot completely solve the problem of balancing OLED luminous efficiency, life span and cost, and there is room for further improvement. Summary of the invention

[0010] Through in-depth research, the researchers of the present invention discovered an ingenious molecular design scheme, which resulted in a compound with more balanced luminescence efficiency and lifespan characteristics, and the compound is particularly suitable for thermally activated delayed fluorescence luminescence.

[0011] Specifically, the present invention provides an organic compound, characterized in that it has a structure shown in formula (1); having a structure shown in formula (1),

[0012]

[0013] Where: D 1 A group represented by formula (2)

[0014]

[0015] X1 ~X 8 Independently selected from N, CH or CR 1 , R 1 is independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, halogen, cyano, nitro, hydroxyl, amino, substituted or unsubstituted C1-C30 silyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and the adjacent R 1 are connected to form a ring or not connected to form a ring, and X 1 ~X 8 0 to 2 of them are N, X 1 ~X 8 At least one of them is CR 1 ;

[0016] D 2 is a group represented by formula (3),

[0017]

[0018] X 9 ~X 16 Independently select N, CH or CR 2 , R 2 is independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, halogen, cyano, nitro, hydroxyl, amino, substituted or unsubstituted C1-C30 silyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and the adjacent R 2 are connected to form a ring or not connected to form a ring, and X 9 ~X 16 0 to 2 of them are N, X 9 ~X 16 At least one of them is CR 2 ;

[0019] D 1 Different from D2;

[0020] D 3 A group represented by formula (4):

[0021]

[0022] Y 1 ~Y 8 Independently selected from N, CH or CR 3 , R 3is independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, halogen, cyano, nitro, hydroxyl, amino, substituted or unsubstituted C1-C30 silyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and the adjacent R 3 are connected to form a ring or not; a is an integer from 0 to 2;

[0023] R is selected from one of hydrogen, halogen, nitro, hydroxyl, amino, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 silyl, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C3-C60 heteroarylamino, substituted or unsubstituted C6-C60 aryl, and substituted or unsubstituted C3-C60 heteroaryl;

[0024] The groups in the above “substituted or unsubstituted” are substituted by one or a combination of at least two selected from C1-C30 alkyl, C1-C30 alkoxy, halogen, cyano, nitro, hydroxyl, amino, C1-C30 silyl, C6-C30 aryl, and C3-C30 heteroaryl.

[0025] It should be noted that in this specification, the expression of Ca to Cb means that the number of carbon atoms in the group is a to b. Unless otherwise specified, the number of carbon atoms does not include the number of carbon atoms in the substituent. In the present invention, the expression of chemical elements, unless otherwise specified, usually includes the concept of isotopes with the same chemical properties. For example, the expression of "hydrogen" also includes the concept of "deuterium" and "tritium" with the same chemical properties. Carbon (C) includes 12 C. 13 C, etc., no further details.

[0026] In the structural formula disclosed in this specification, the expression of the ring structure crossed by “—” indicates that the connection site is any position on the ring structure that can form a bond, and “*” indicates the connection site.

[0027] In this specification, unless otherwise specified, aryl and heteroaryl include both monocyclic and condensed rings. The so-called monocyclic aryl refers to a molecule containing at least one phenyl group. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, such as phenyl, biphenyl, terphenyl, etc.; condensed ring aryl refers to a molecule containing at least two benzene rings, but the benzene rings are not independent of each other, but condensed to each other by sharing the ring edge, such as naphthyl, anthracenyl, etc.; monocyclic heteroaryl refers to a molecule containing at least one heteroaryl group. When the molecule contains one heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and other groups are independent of each other and connected by a single bond, such as pyridine, furan, thiophene, etc.; condensed ring heteroaryl refers to a molecule composed of at least one phenyl group and at least one heteroaryl group fused together, or at least two heteroaryl rings fused together, such as quinoline, isoquinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, etc.

[0028] In this specification, substituted or unsubstituted C 6 ~C 30 The aryl group is preferably C 6 ~C 20 The aryl group is more preferably a group selected from the group consisting of phenyl, naphthyl, anthracenyl, benzanthryl, phenanthryl, triphenylenyl, pyrenyl, chrysene, peryl, fluoranthenyl, tetraphenyl, pentacene, benzopyrenyl, biphenyl, phenylene, terphenyl, triphenylene, quaterphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indenofluorenyl, trimerized indenyl, isotrimerized indenyl, spirotrimerized indenyl, and spiroisotrimerized indenyl. Specifically, the biphenyl group is selected from 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl group includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl group includes 1-naphthyl or 2-naphthyl; the anthracenyl group is selected from 1-anthracenyl, 2-anthracenyl and 9-anthracenyl; the fluorenyl group is selected from 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl and 9-fluorenyl; the pyrenyl group is selected from 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the tetraphenyl group is selected from 1-tetraphenyl, 2-tetraphenyl and 9-tetraphenyl. Preferred examples of the aryl group in the present invention include phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl and its derivatives, fluoranthenyl, triphenylene, pyrenyl, peryl, The biphenyl group is selected from the group consisting of 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl group includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl group includes 1-naphthyl or 2-naphthyl; the anthracenyl group is selected from the group consisting of 1-anthracenyl, 2-anthracenyl and 9-anthracenyl. The fluorenyl group is selected from the group consisting of 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl and 9-fluorenyl; the fluorenyl derivative is selected from the group consisting of 9,9-dimethylfluorene, 9,9-spirobifluorene and benzofluorene; the pyrenyl group is selected from the group consisting of 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the naphthyl group is selected from the group consisting of 1-naphthyl, 2-naphthyl and 9-naphthyl.

[0029] The heteroatom in the present invention is generally selected from N, O, S, P, Si and Se, preferably selected from N, O and S.

[0030] In the present specification, the substituted or unsubstituted C3-C30 heteroaryl group is preferably a C4-C20 heteroaryl group, and more preferably a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, a sulfur-containing heteroaryl group, etc. Specific examples include: furyl, thienyl, pyrrolyl, pyridyl, benzofuranyl, benzothienyl, isobenzofuranyl, isobenzothienyl, indolyl, isoindolyl, dibenzofuranyl, dibenzothienyl, carbazolyl and its derivatives, quinolyl, isoquinolyl, acridinyl, phenanthridine yl, benzo-5,6-quinolyl, benzo-6,7-quinolyl, benzo-7,8-quinolyl, phenothiazinyl, phenazinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthoimidazolyl, phenanthroimidazolyl, pyridoimidazolyl, pyrazinoimidazolyl, quinoxalinoimidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthrazolyl, phenanthroxazolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyridazinyl, pyrimidazinyl, pyridinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthryl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazaperyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbolinyl, phenanthrolinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, benzotriazolyl, 1,2,3-oxadiazolyl, oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazolyl, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purinyl, pteridinyl, indolizine, benzothiadiazole and the like. Preferred examples of heteroaryl groups in the present invention include furyl, thienyl, pyrrolyl, benzofuranyl, benzothienyl, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothienyl, carbazolyl and derivatives thereof, wherein the carbazolyl derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole, benzocarbazole, dibenzocarbazole or indolecarbazole.

[0031] In the present specification, the alkyl group includes chain and cyclic alkyl groups. Examples of the C1 to C30 alkyl group include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, adamantyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, and the like.

[0032] In the present specification, the cycloalkyl group includes a monocyclic alkyl group and a polycyclic alkyl group, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a dicyclopentyl group, and the like.

[0033] In the present specification, the C1-C30 alkoxy group is a monovalent group composed of the above-mentioned alkyl group and an oxygen atom, and examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, etc., among which methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, sec-butoxy, isobutoxy, isopentyloxy, and methoxy is more preferred.

[0034] In the present specification, examples of C1-C30 silyl groups include silyl groups substituted with the groups listed in the above C1-C30 alkyl groups, specifically including methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl, diethylsilyl, triethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl and the like.

[0035] In the present specification, examples of halogen include fluorine, chlorine, bromine, and iodine.

[0036] In the present invention, the "substituted or unsubstituted" group may be substituted with one substituent or with multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the same expressions are involved in the present invention, they all have the same meaning, and the selection range of substituents is as shown above and will not be repeated one by one.

[0037] In the present invention, it is very important that there are two N-carbazole substituents at the ortho position of the above-mentioned benzonitrile, and the entire benzene ring core has more than 4 carbazole substituents. The inventors of the present invention have found that when there are two N-carbazole substituents at the ortho position of benzonitrile according to the present invention, the compound is particularly suitable for use as a thermally activated delayed fluorescence luminescent material, and can achieve very good device efficiency through triplet energy crossing, that is, the excitation voltage will be reduced and the current efficiency will be improved.

[0038] For the compound represented by formula (1) of the present invention, from the viewpoint of further improving the technical effect of the present invention, it is preferred that D 1 In, R 1 is independently selected from a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group, X 1 ~X 8 One of them is N or none of them is N, X 1 ~X 8 At least 1-2 of them are CR 1 ;

[0039] D 2 In, R 2is independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, X 9 ~X 16 One of them is N or none of them is N, X 9 ~X 16 At least 1-2 of them are CR 2 ; a can be 1 or 2, preferably a is 2.

[0040] Furthermore, the present inventors have found through continuous in-depth research that the performance of the compound of the present invention can be further optimized by the following molecular design method. That is, the compound of the present invention is preferably a compound represented by the following formula (5):

[0041]

[0042] In formula (5), D 1 In, R 1 is independently selected from a substituted or unsubstituted C1-C10 chain alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C1-C10 alkoxy group, 1 ~X 8 One of them is N or none of them is N, X 1 ~X 8 At least 1-2 of them are CR 1 ,

[0043] D 2 In, R 2 is independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, X 9 ~X 16 One of them is N or none of them is N, X 9 ~X 16 At least 1-2 of them are CR 2 ,

[0044] D 3 Middle, Y 1 ~Y 4 All are CH, or Y 1 ~Y 4 One or two of them are N and the rest are CH, Y 5 ~Y 8 All are CH, or Y 5 ~Y 8 One or two of them are N, the rest are CH, and two D 3 Can be the same or different.

[0045] Specifically, in the compound of the present invention, if one of the two carbazole groups substituted at the ortho position of benzonitrile is substituted by a saturated alkyl group or a saturated alkoxy group (D 1 ), the other is substituted with an aromatic substituent (D 2 ), not only can very good device efficiency be achieved, but also the obtained compound can be more stable, thereby taking into account the device life and achieving a perfect balance between efficiency and life. The specific reasons why the above-mentioned compounds of the present invention are used as luminescent dyes and / or sensitizers in organic electroluminescent devices are excellent are still unclear, and it is speculated that the following reasons may be the reason: the appropriate steric hindrance of the alkyl group can reduce concentration quenching, and the aryl or heteroaryl group can increase the conjugation within the molecule, which is beneficial to carrier transport, which is beneficial to enhancing the stability of the compound, and can also improve the fluorescence quantum yield and increase the reverse intersystem crossing rate. Only when one of the two carbazole groups substituted at the ortho position of benzonitrile is substituted by a saturated alkyl or saturated alkoxy group and the other is substituted by an aromatic substituent, the advantages of the alkyl substituent and the advantages of the aromatic substituent can be exerted at the same time, thereby improving the external quantum efficiency and life of the device.

[0046] At the same time, the inventors of the present invention also found that when the carbazole substituent at the meta-position of benzonitrile (D 3 ) is a carbazole-type substituent without a substitution group, which is more conducive to carrier transport and thus reduces the device voltage, and is therefore preferred.

[0047] In the present invention, as D 1 The position of the substituent in is preferably X 3 and / or X 6 The position of D 2 The position of the substituent in is preferably X 11 and / or X 14 , the positions of these substituents are not essential, but when D 1 The substituent is located at X 3 and / or X 6 When D 2 The position of the substituent in X 11 and / or X 14 When the reaction mixture is added, it is more conducive to enhancing the stability and carrier transport ability of the compound.

[0048] D 1 and D 2 The carbazole group can be replaced by one N-hybridization. If the number of N-hybridization replacements is too large, it may be due to D 1 and D 2Too strong electron-withdrawing property leads to loss of the effect of the present invention.

[0049] As a further preferred R 1 Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, methoxy, isopropoxy, etc.

[0050] More specifically, as D 1 Preferred examples include the following groups:

[0051]

[0052] As a further preferred R 2 Examples of the group include phenyl, pyridyl, furyl, thienyl, pyrrolyl, and groups in which these groups are substituted with a C1-C3 alkyl group.

[0053] More specifically, as D 2 Preferred examples include the following groups:

[0054]

[0055] In the compound of the present invention, R is preferably a hydrogen atom.

[0056] The two D in formula (5) of the present invention are 3 can be the same or different, preferably all are carbazole groups, but the carbazole group can be replaced by 1 to 2 N hybridizations, that is, wherein Y 1 ~Y 4 One or two of them are N and the rest are CH, among which Y 5 ~Y 8 One or two of them are N and the rest are CH. It is preferred to be replaced by 0-1 N hybridization. If the number of N hybridization is too large, it may cause D 3 , D 4 The electron-withdrawing ability of D is too strong, which is not conducive to the increase of the electron cloud density of the benzonitrile core and destroys the carrier transport property. 3 , D 4 Preferably selected from the following groups:

[0057]

[0058] More preferred are the following groups:

[0059]

[0060] Unsubstituted carbazole groups are particularly preferred, with two D 3 When all are unsubstituted carbazole groups, the carrier transport capacity of the compound of the present invention is the highest.

[0061] Furthermore, the organic compound of the present invention can preferably include the specific structural compounds shown below, which are only representative and do not limit the scope of the present invention.

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] In addition, the preparation process of the compound of the present invention is simple and easy, the raw materials are easily available, it is suitable for mass production and expansion, and is very suitable for industrial application.

[0071] The above-mentioned compound of the present invention has excellent luminescent properties, can provide triplet excitons to achieve higher luminescent efficiency, and is suitable for use as a luminescent dye, especially as a blue luminescent dye, based on its excellent carrier transfer efficiency. Of course, since the compound of the present invention can also be used as a sensitizer together with the host material and the dye to achieve a good luminescent layer. The devices used include but are not limited to organic electroluminescent devices, optical sensors, solar cells, lighting elements, organic thin film transistors, organic field effect transistors, organic thin film solar cells, information tags, electronic artificial skin sheets, sheet-type scanners or electronic paper, preferably organic electroluminescent devices.

[0072] The present invention also provides an organic electroluminescent device, which comprises a first electrode, a second electrode and at least one or more light-emitting functional layers inserted between the first electrode and the second electrode, wherein the light-emitting functional layer contains at least one compound described in the present invention.

[0073] The organic electroluminescent device of the present invention has the same structure as the existing devices, for example, including an anode layer, multiple light-emitting functional layers and a cathode layer; the multiple light-emitting functional layers at least include a light-emitting layer, wherein the light-emitting layer contains the above-mentioned organic compound of the present invention.

[0074] The present invention further discloses a display screen or a display panel, wherein the organic electroluminescent device as described above is adopted in the display screen or the display panel; preferably, the display screen or the display panel is an OLED display.

[0075] The present invention also discloses an electronic device, wherein the electronic device has a display screen or a display panel, and the display screen or the display panel adopts the organic electroluminescent device as described above.

[0076] The OLED device prepared by using the compound of the present invention has low starting voltage, high luminous efficiency and better service life, and can meet the requirements of current panel and display manufacturers for high-performance materials. DETAILED DESCRIPTION

[0077] The technical solution of the present invention is further described in more detail below. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Throughout the specification, reference to "some embodiments", "embodiments", "an example" or "example" means that specific features, structures or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment", "in an embodiment", "an example" or "example" that appear in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, specific features, structures or characteristics can be combined in one or more embodiments or examples in any appropriate combination and / or sub-combination. In addition, it should be understood by those of ordinary skill in the art that the term "and / or" used herein includes any and all combinations of one or more related listed items.

[0078] Method for obtaining the compound of the present invention

[0079] The compound represented by the general formula (1) of the present invention can be obtained by a known method, for example, by a known organic synthesis method. An exemplary synthesis route is given below, but those skilled in the art can also obtain it by other known methods.

[0080] The general synthesis formula is as follows:

[0081]

[0082] The present invention will be described in detail below with reference to a number of specific embodiments. The compounds of the embodiments of the present invention can be synthesized with reference to the specific synthesis examples shown below, but it should be noted that obtaining the compound is not limited to the synthesis method and raw materials used in the present invention, and those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. The compounds for which the synthesis method is not mentioned in the present invention are raw materials obtained from commercial channels, or are prepared by these raw materials according to known methods.

[0083] The structure of the organic electroluminescent device of the present invention is a known structure, and is characterized in that the compound of the present invention is used in the electron transport layer and / or the electron injection layer. The organic electroluminescent device is described in detail below.

[0084] OLED includes a first electrode, a second electrode, and an organic material layer between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0085] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0086] The first electrode can be formed by sputtering or depositing a material used as the first electrode on the substrate. When the first electrode is used as an anode, indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO 2 ), zinc oxide (ZnO) and other oxide transparent conductive materials and any combination thereof. When the first electrode is used as a cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), ytterbium (Yb), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and the like and any combination thereof can be used.

[0087] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0088] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multilayer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); wherein the HIL is located between the anode and the HTL, and the EBL is located between the HTL and the light-emitting layer.

[0089] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-51 below; or any combination thereof.

[0090]

[0091]

[0092]

[0093] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-51 above, or one or more compounds of HI-1 to HI-3 below; or one or more compounds of HT-1 to HT-51 can be doped with one or more compounds of HI-1 to HI-3 below.

[0094]

[0095] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit light of different wavelength spectra, and may also include a host material (Host). The light-emitting layer may be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors may be arranged in a plane according to a pixel pattern, or may be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they may be separated from each other or may be connected to each other. The light-emitting layer may also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0096] According to different technologies, the light-emitting layer material can be made of different materials such as fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescent materials. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0097] In one aspect of the present invention, the light-emitting layer adopts the technology of thermally activated delayed fluorescence luminescence. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of the above PH-1 to PH-85.

[0098]

[0099]

[0100]

[0101] In one aspect of the present invention, an electron blocking layer (EBL) is located between the hole transport layer and the light emitting layer. The electron blocking layer may be, but not limited to, one or more of the compounds HT-1 to HT-51 described above, or one or more of the compounds PH-47 to PH-77 described above; or a mixture of, but not limited to, one or more of the compounds HT-1 to HT-51 and one or more of the compounds PH-47 to PH-77.

[0102] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0103] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-73 listed below.

[0104]

[0105]

[0106]

[0107] In one aspect of the present invention, a hole blocking layer (HBL) is located between the electron transport layer and the light emitting layer. The hole blocking layer may be, but not limited to, one or more compounds of ET-1 to ET-73, or one or more compounds of PH-1 to PH-46; or a mixture of one or more compounds of ET-1 to ET-73 and one or more compounds of PH-1 to PH-46.

[0108] The device may further include an electron injection layer located between the electron transport layer and the cathode. Materials for the electron injection layer include, but are not limited to, one or more combinations of the following.

[0109] LiQ, LiF, NaCl, CsF, Li 2 O、Cs 2 CO 3 , BaO, Na, Li, Ca, Yb, Mg.

[0110] Example

[0111] In the following, the organic compounds of the present invention are representatively synthesized and applied together with corresponding comparative compounds to organic electroluminescent devices to test the device performance under the same conditions.

[0112] The solvents and reagents used in the synthesis examples, such as dichloromethane, petroleum ether, ethanol, tetrahydrofuran, N, N-dimethylacetamide, anhydrous magnesium sulfate, carbazole, benzimidazole and other chemical reagents, can be purchased from the domestic chemical product market, such as Sinopharm Group Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, Bailingwei Reagent Company, etc. In addition, those skilled in the art can also synthesize by known methods.

[0113] In addition, the mass spectrometry characterization data in the following synthetic examples were obtained by ABSCIEX (4000QTRAP) mass spectrometer testing.

[0114] Synthesis Example

[0115] Synthesis Example 1: Synthesis of S2:

[0116]

[0117] At room temperature, 2,3,5,6-tetrafluorobenzonitrile (20 g, 114.23 mmol), 1 (31.92 g, 114.23 mmol) and potassium carbonate (31.57 g, 228.46 mmol) were dissolved in DMF (500 ml) and reacted at room temperature overnight. 1000 ml of dichloromethane was added, and water (500 ml) was added to wash 5 times, and the liquid was separated. The organic phase was collected and concentrated, and ethanol (1000 ml) was added at room temperature and stirred for 2 hours. The white solid product M2-1 was filtered and vacuum dried to obtain 35 g.

[0118] At room temperature, M2-1 (5 g, 11.51 mmol), 2 (3.68 g, 11.51 mmol) and potassium carbonate (3.18 g, 23.01 mmol) were added to a 250 ml single-mouth bottle, DMF (50 ml) was used as solvent, and the reaction was carried out at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, and the liquid was separated, and the organic phase was collected and concentrated. Ethanol (1000 ml) was added at room temperature and stirred for 2 hours, and the white solid product M2-2 was obtained by filtration, and 5 g was obtained by vacuum drying.

[0119] At room temperature, M2-2 (6 g, 8.18 mmol), 3 (2.87 g, 17.17 mmol) and cesium carbonate (6.66 g, 20.44 mmol) were added to a 250 ml single-mouth bottle, DMF (50 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol and dried in vacuo to obtain 6 g of white solid product S2.

[0120] Synthesis Example 2: Synthesis of S4:

[0121]

[0122] At room temperature, 2,3,5,6-tetrafluorobenzonitrile (10 g, 57.11 mmol), 4 (12.98 g, 57.11 mmol) and potassium carbonate (19.73 g, 142.79 mmol) were dissolved in DMF (400 ml) and reacted at room temperature overnight. 1000 ml of dichloromethane was added, and water (500 ml) was added to wash 5 times, and the liquid was separated. The organic phase was collected and concentrated, and ethanol (1000 ml) was added at room temperature and stirred for 2 hours. The white solid product M4-1 was filtered and dried to obtain 17 g.

[0123] At room temperature, M4-1 (10 g, 26.15 mmol), 5 (8.35 g, 26.15 mmol) and potassium carbonate (7.23 g, 52.31 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the reaction was carried out at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, and the liquid was separated, and the organic phase was collected and concentrated. Ethanol (1000 ml) was added at room temperature and stirred for 2 hours, and the white solid product M4-2 was obtained by filtration, and 14 g was obtained by drying.

[0124] Synthesis of final product S4:

[0125] At room temperature, M4-2 (10 g, 14.67 mmol), 3 (5.15 g, 30.80 mmol) and cesium carbonate (10.51 g, 32.27 mmol) were added to a 500 ml single-mouth bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation was precipitated, and the filter cake was recrystallized from toluene / ethanol to obtain 10 g of white solid product S4.

[0126] Synthesis Example 3: Synthesis of S7:

[0127]

[0128] At room temperature, 2,3,5,6-tetrafluorobenzonitrile (20 g, 114.23 mmol), 6 (31.92 g, 114.23 mmol) and potassium carbonate (31.57 g, 228.46 mmol) were dissolved in DMF (500 ml) and reacted at room temperature overnight. 1000 ml of dichloromethane was added, and water (500 ml) was added to wash 5 times, and the liquid was separated, and the organic phase was collected and concentrated. Ethanol (1000 ml) was added at room temperature and stirred for 2 hours, and the white solid product M7-1 was obtained by filtration, and 30 g was obtained by drying.

[0129] At room temperature, M2-1 (5 g, 11.51 mmol), 7 (3.70 g, 11.51 mmol) and potassium carbonate (3.18 g, 23.01 mmol) were added to a 250 ml single-mouth bottle, DMF (50 ml) was used as solvent, and the mixture was reacted at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, the liquid was separated, the organic phase was collected, concentrated, ethanol (1000 ml) was added to stir at room temperature for 2 hours, and the white solid product M7-2 was obtained by filtration, and 8 g was obtained by drying.

[0130] At room temperature, M7-2 (7.5 g, 10.19 mmol), 3 (3.41 g, 20.38 mmol) and cesium carbonate (8.3 g, 25.48 mmol) were added to a 250 ml single-mouth bottle, DMF (50 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 5 g of white solid product S7.

[0131] Synthesis Example 4: Synthesis of S11:

[0132]

[0133] At room temperature, 2,3,5,6-tetrafluorobenzonitrile (20 g, 114.23 mmol), 8 (28.71 g, 114.23 mmol) and potassium carbonate (31.57 g, 228.46 mmol) were dissolved in DMF (500 ml) and reacted at room temperature overnight. 1000 ml of dichloromethane was added, and water (500 ml) was added to wash 5 times, and the liquid was separated. The organic phase was collected and concentrated, and ethanol (1000 ml) was added at room temperature and stirred for 2 hours. The white solid product M11-1 was filtered and dried to obtain 25 g.

[0134] At room temperature, M11-1 (10 g, 24.60 mmol), 9 (8.55 g, 24.60 mmol) and potassium carbonate (4.08 g, 29.52 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the mixture was reacted at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, the liquid was separated, the organic phase was collected, concentrated, ethanol (1000 ml) was added to stir for 2 hours at room temperature, and the white solid product M11-2 was obtained by filtration, and 12 g was obtained by drying.

[0135] At room temperature, M11-2 (12 g, 16.35 mmol), 3 (5.74 g, 34.34 mmol) and cesium carbonate (11.72 g, 35.97 mmol) were added to a 500 ml single-mouth bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 7 g of white solid product S11.

[0136] Synthesis Example 5: Synthesis of S12:

[0137]

[0138] At room temperature, 2,3,5,6-tetrafluorobenzonitrile (20 g, 114.23 mmol), 10 (28.83 g, 114.23 mmol) and potassium carbonate (31.57 g, 228.46 mmol) were dissolved in DMF (500 ml) and reacted at room temperature overnight. 1000 ml of dichloromethane was added, and water (500 ml) was added to wash 5 times, and the liquid was separated. The organic phase was collected and concentrated, and ethanol (1000 ml) was added at room temperature and stirred for 2 hours. The white solid product M11-1 was filtered and dried to obtain 37 g.

[0139] At room temperature, M12-1 (10 g, 24.56 mmol), 11 (8.53 g, 24.56 mmol) and potassium carbonate (4.07 g, 29.47 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the mixture was reacted at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, the liquid was separated, the organic phase was collected, concentrated, ethanol (500 ml) was added to stir at room temperature for 2 hours, and the white solid product M12-2 was obtained by filtration, and 15 g was obtained by drying.

[0140] At room temperature, M12-2 (15 g, 19.70 mmol), 3 (6.59 g, 39.4 mmol) and cesium carbonate (14.12 g, 43.34 mmol) were added to a 500 ml single-necked bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 15 g of white solid product S12.

[0141] Synthesis Example 6: Synthesis of S19:

[0142]

[0143] At room temperature, M2-1 (5 g, 11.51 mmol), 12 (3.68 g, 11.51 mmol) and potassium carbonate (3.18 g, 23.02 mmol) were added to a 250 ml single-mouth bottle, DMF (50 ml) was used as solvent, and the reaction was carried out at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, and the liquid was separated, and the organic phase was collected and concentrated. Ethanol (1000 ml) was added at room temperature and stirred for 2 hours, and the white solid product M19-1 was obtained by filtration, and 7.2 g was obtained by drying.

[0144] At room temperature, M19-1 (7 g, 9.53 mmol), 3 (3.19 g, 19.06 mmol) and cesium carbonate (6.83 g, 20.97 mmol) were added to a 500 ml single-mouth bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 4 g of white solid product S19.

[0145] Synthesis Example 7: Synthesis of S22:

[0146]

[0147] At room temperature, M2-1 (10 g, 23.01 mmol), 13 (5.60 g, 23.01 mmol) and potassium carbonate (4.77 g, 34.52 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the mixture was reacted at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, the liquid was separated, the organic phase was collected, concentrated, ethanol (500 ml) was added to stir at room temperature for 2 hours, and the white solid product M22-1 was obtained by filtration, and 13 g was obtained by drying.

[0148] At room temperature, M22-1 (12 g, 18.26 mmol), 14 (6.14 g, 36.51 mmol) and cesium carbonate (13.09 g, 40.17 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 7.3 g of white solid product S22.

[0149] Synthesis Example 8: Synthesis of S62:

[0150]

[0151] At room temperature, M11-1 (10 g, 24.60 mmol), 15 (8.74 g, 24.60 mmol) and potassium carbonate (5.10 g, 36.9 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the reaction was carried out at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, and the liquid was separated, and the organic phase was collected and concentrated. Ethanol (500 ml) was added at room temperature and stirred for 2 hours, and the white solid product M69-1 was obtained by filtration, and 13 g was obtained by drying.

[0152] At room temperature, M69-1 (10 g, 13.48 mmol), 3 (4.73 g, 28.31 mmol) and cesium carbonate (9.22 g, 28.31 mmol) were added to a 500 ml single-mouth bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 8.2 g of white solid product S62.

[0153] Synthesis Example 9: Synthesis of S78:

[0154]

[0155] At room temperature, M11-1 (10 g, 24.60 mmol), 16 (9.04 g, 24.60 mmol) and potassium carbonate (5.10 g, 36.9 mmol) were added to a 250 ml single-mouth bottle, DMF (100 ml) was used as solvent, and the reaction was carried out at 50°C for 4 hours. 500 ml of dichloromethane was added, and water (50 ml) was added to wash 5 times, the liquid was separated, the organic phase was collected, concentrated, ethanol (500 ml) was added to room temperature, stirred for 2 hours, filtered to obtain a white solid product M78-1, and dried to obtain 15 g.

[0156] At room temperature, M78-1 (10 g, 13.26 mmol), 3 (4.66 g, 27.85 mmol) and cesium carbonate (9.08 g, 27.85 mmol) were added to a 500 ml single-mouth bottle, DMF (200 ml) was used as solvent, and the reaction was carried out at 80°C overnight. After cooling to room temperature, water was added to the reaction solution while stirring until no more precipitation occurred, and the filter cake was recrystallized from toluene / ethanol to obtain 7.5 g of white solid product S78.

[0157] Synthesis of comparative compound R-3: The specific method refers to the synthesis method in the document “Tert-butyl Substituted Hetero-donor TADF compounds for Efficient Solution-Processed Non-doped Blue OLEDs”, and its description is omitted here.

[0158]

[0159] Synthesis of comparative compounds R-1 and R-2: The specific method refers to the synthesis method in patent document US20190181353, and its description is omitted here.

[0160]

[0161] Synthesis of comparative compound R-4: The specific method refers to the synthesis method in patent document CN110366548A, and its description is omitted here.

[0162]

[0163] Device Embodiment

[0164] Example 1

[0165] The preparation process of organic electroluminescent device is as follows:

[0166] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0167] Place the glass substrate with the anode in a vacuum chamber and evacuate to a vacuum of <1×10 -5 Pa, on the above anode layer film, vacuum thermal evaporation was performed in order of 10nm of HT-4:HI-3 (97 / 3, w / w) mixture as a hole injection layer, 60nm of compound HT-4 as a hole transport layer, 5nm of compound HT-51 as an electron blocking layer; 40nm of compound PH-54:S2 (100:40, w / w) binary mixture as a light-emitting layer, 5nm of PH-28 as a hole blocking layer, 25nm of compound ET-69:ET-57 (50 / 50, w / w) mixture as an electron transport layer, 1nm of LiF as an electron injection layer, and 150nm of metal aluminum as a cathode. The total evaporation rate of all organic layers and LiF was controlled at 0.1nm / sec, and the evaporation rate of the metal electrode was controlled at 1nm / sec.

[0168] The preparation process of device examples 2-11 and comparative examples 1-4 is the same as that of device example 1, except that the compound S2 of the present invention as the luminescent dye is replaced by the compounds S4, S7, S11, S12, S19, S22, S62, S78, S135 of the present invention and the compounds R-1, R-2, R-3 and R-4 of the prior art, respectively.

[0169] The organic electroluminescent device prepared by the above process was subjected to the following performance tests:

[0170] At the same brightness, the driving voltage and device life of the organic electroluminescent device prepared from the compound and the comparative material were measured using a digital source meter and a brightness meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the brightness of the organic electroluminescent device was measured when it reached 1000 cd / m 2The voltage at which the luminance is measured is the driving voltage. 2 At the same brightness, the current is kept constant and the brightness of the organic electroluminescent device is measured to drop to 950cd / m 2 The time in hours.

[0171] The specific performance data of the organic electroluminescent devices prepared in the above-mentioned Examples 1-11 and Comparative Examples 1-4 of the present invention are shown in Table 1 below, wherein the lifetime value of Comparative Example 1 is taken as 1.0, and the lifetime values ​​in other Examples are ratios thereto.

[0172] Table 1

[0173]

[0174] The above results show that the novel compounds of the present invention are used in organic electroluminescent devices. Compared with R-1, the compounds in the examples have an additional aromatic conjugation at the ortho-carbazole position of the cyano group, which enhances the stability and carrier transport capacity of the compounds, thus facilitating the reduction of device voltage and significantly improving device life.

[0175] Compared with R-2, the compound in the embodiment has a carbazole aromatic conjugated group at the ortho position of the cyano group, and the other carbazole is substituted by an alkyl group. The large steric hindrance alkyl group can increase the twist angle between the donor and the acceptor while keeping the twist angle within a certain range, which is beneficial to enhancing the TADF properties of the material itself. Therefore, when the external quantum efficiency and device life do not change much, the device voltage is significantly reduced and the device life is significantly improved.

[0176] Compared with R-4, the example compound has two unsubstituted carbazoles, which is beneficial to carrier transport, thereby reducing the device voltage and improving the device life.

[0177] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0178] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. An organic compound, characterized in that Having the structure shown in formula (5), Where: D 1 is one of the following groups, D 2 is one of the following groups, D 3 A group represented by formula (4): Y 1 ~Y 8 Independently selected from N, CH or CR 3 , R 3 is independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group; R is hydrogen; The above-mentioned "substituted or unsubstituted" groups are substituted by one or more groups selected from C1-C30 alkyl, C1-C30 alkoxy, halogen, cyano, nitro, hydroxyl, amino, C1-C30 silyl, C6-C30 aryl, and C3-C30 heteroaryl.

2. The organic compound according to claim 1, wherein D 3 Middle, Y 1 ~Y 4 All are CH, or Y 1 ~Y 4 One or two of them are N and the rest are CH, Y 5 ~Y 8 All are CH, or Y 5 ~Y 8 One or two of them are N, the rest are CH, and two D 3 Can be the same or different.

3. The organic compound according to claim 1, wherein Y 1 ~Y 8 are independently selected from N or CH.

4. The organic compound according to claim 1, wherein Y 1 ~Y 8 All are CH.

5. Compounds having the following structure: 6 . An organic electroluminescent material, which is the compound according to claim 1 . 7 . A thermally activated delayed fluorescent light-emitting material, which is the compound according to claim 1 .

8. Use of the compound according to any one of claims 1 to 5 as a thermally activated delayed fluorescence luminescent material.

9. An organic electroluminescent device comprising a first electrode, a second electrode and one or more light-emitting functional layers inserted between the first electrode and the second electrode, wherein the light-emitting functional layer contains the compound according to any one of claims 1 to 5. 10 . The organic electroluminescent device according to claim 9 , wherein the plurality of light-emitting functional layers include a light-emitting layer, and the light-emitting layer contains the organic compound according to claim 1 .

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