Luminescent layer material with spiral structure, preparation method thereof and organic electroluminescent device

Abstract

The invention relates to the technical field of organic photoelectric materials, in particular to a luminescent layer material with a spiro structure, a preparation method of the luminescent layer material and an organic electroluminescent device, and the luminescent layer material is a compound with a structure as shown in a formula (I). The synthesis and purification method of the compound is simple and easy to implement, and the compound has excellent photoelectric properties, can be used as an organic light-emitting layer material of an organic light-emitting diode, and is used for preparing the organic light-emitting diode with high external quantum efficiency, low efficiency roll-off and long service life. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of organic photoelectric materials, and relates to a luminescent layer material with a spiro ring structure, a preparation method thereof, and an organic electroluminescent device. Background Art

[0002] Compared with liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs) do not require a backlight layer or a liquid crystal layer. In addition, OLED devices have the advantages of high color contrast, wide viewing angle, fast response time, thin and foldable, low manufacturing cost, and good adaptability to low temperature environments. At present, OLED technology is becoming the mainstream direction of display technology development and is expected to replace LCD as the next generation mainstream display technology.

[0003] OLED is generally composed of an anode, a metal cathode and an organic functional layer located between the two. The organic functional layer mainly includes a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. Among them, the light-emitting layer is the core functional layer and directly determines the performance of the entire device. Generally speaking, the light-emitting layer mostly adopts a host-guest structure, that is, the light-emitting material is doped in the main material at a certain concentration to avoid quenching caused by the aggregation of the light-emitting material, thereby improving the OLED light-emitting efficiency. In addition, in order to improve the performance of OLED devices, sensitized OLEDs with main materials, sensitizers and fluorescent light-emitting materials as the light-emitting layer have been proposed in recent years.

[0004] Generally, the host material needs to have a high triplet energy level and excellent carrier transport ability, and should also have high thermal stability and chemical stability. Thermally activated delayed fluorescence (TADF) materials can be used as both luminescent materials and sensitizer materials. Such materials usually have a small singlet-triplet energy level difference (ΔE ST ), so that triplet excitons can be converted into singlet excitons through the anti-intersystem crossing (RISC) process to emit light. Therefore, when used as a luminescent material, TADF materials can effectively utilize singlet excitons and triplet excitons generated under electrical excitation, so that the internal quantum efficiency (IQE) of the device can reach 100%, so it is called the third generation of organic electroluminescent materials. In sensitized OLED devices, TADF materials act as sensitizers, and their main function is to convert their own triplet excitons into singlet excitons through the RISC process, and then through The energy is transferred to the fluorescent material with high color purity, sensitizing the fluorescent molecules to emit light. This device structure fully utilizes the advantage of high utilization rate of TADF excitons, while also solving the color purity problem caused by direct light emission of TADF materials. Therefore, whether as a light-emitting material or as a sensitizer material, TADF materials need to have a faster RISC rate. Since traditional fluorescent materials have excellent color purity and high stability, the blue light materials in current commercial OLED devices are still fluorescent materials. Fluorescent materials need to have high fluorescence quantum yield (PLQY) and be able to suppress aggregate luminescence quenching, and should also have high thermal stability and chemical stability.

[0005] Spirocyclic structures are an important building block of organic semiconductor materials. Their unique non-planar spiro conjugation effect, vertical orthogonal conformation and steric hindrance effect can effectively improve the optoelectronic properties and stability of organic semiconductor materials. Spirocyclic compounds not only have high thermal stability, chemical stability and carrier transport properties, but also have suitable singlet, triplet and molecular orbital energy levels, so they are excellent building blocks of OLED main materials; in addition, the spirocyclic structure can also be used as a rigid bridging group to connect the electron-donating group and the electron-accepting group, which can simultaneously achieve a smaller ΔE ST and higher PLQY, constructing high-performance TADF materials; on the other hand, the inherent rigid structure of spiro compounds can effectively inhibit the fluorescence quenching effect caused by intermolecular interactions, making them also suitable as building blocks of fluorescent materials. In summary, the spiro structure is an important unit for constructing OLED main materials, thermally activated delayed fluorescence materials, sensitizer materials and fluorescent luminescent materials due to its unique three-dimensional spatial structure and strong molecular rigidity and stability. The development of new, efficient and stable OLED spiro structure main materials, thermally activated delayed fluorescence materials, sensitizer materials and fluorescent luminescent materials has always been a continuous demand.

[0006] CN111635391A discloses a fluorene compound that can be used as a functional layer material for OLEDs to improve device performance. However, when synthesizing fluorene and six-membered ring linkers, isomers are easily produced due to the presence of multiple active reaction sites, which not only reduces the yield of the reaction, but also increases the difficulty of separating the reaction products. Figure 1 As shown in the figure, when there is no Z group, the carbon atoms occupied by the black balls are all active sites for the reaction, and the reaction products are a pair of isomers. Usually, isomers have similar polarity ( Figure 2The invention discloses a method for preparing the isomers of the compound in CN111635391A, which is difficult to separate and purify, and ultimately results in a reduction in the yield of the target product and a sharp increase in production costs. On the other hand, the invention uses highly dangerous acyl chloride derivatives as initial raw materials. Usually, such raw materials need to be stored at low temperatures, and their storage requirements are relatively strict, and the procurement cost is also relatively high.

[0007] CN112266359A discloses a thermally activated delayed fluorescent material that can be used as a light-emitting material in OLEDs. However, the electron-donating group and the electron-accepting group in the spirocyclic thermally activated delayed fluorescent compound described in this patent are distributed in two independent linkers. Although a donor-acceptor-donor "sandwich" spatial structure is formed, the distribution of the donor and the acceptor in two independent linkers will increase the harmful structural relaxation of the molecule, making the spatial interaction between the donor and the acceptor relatively weak. Therefore, the compound with this structure does not have obvious advantages in promoting the improvement of external quantum efficiency (EQE) and reducing the roll-off of device efficiency.

[0008] The spirocyclic organic compound luminescent materials described in the prior art (CN111440122A, CN111635413A and Nature Materials, 2020, 19, 1332-1338) wherein the electron-donating group and the electron-accepting group can form a spatial charge transfer state, which improves the luminescent performance of the material to a certain extent. However, the spirocyclic compound is composed of a single electron-donating group and a single electron-accepting group, and the spatial charge transfer state formed is weak, and the RISC rate between the triplet state and the singlet state is less than 10 5 s -1 , which limits the efficient utilization of triplet excitons in OLED devices, and the devices show a large efficiency roll-off at high current density, which is not conducive to their practical application.

[0009] The spirocyclic molecule involved in the present invention has a simple synthesis method and high yield, and the compact spatial stacking structure formed by it significantly improves the rigidity and stability of the molecule. At the same time, the structure creates multiple charge transfer state channels, which helps to improve the luminous efficiency and RISC rate of the material, thereby greatly improving the performance in OLED. Summary of the invention

[0010] Problem that the invention aims to solve

[0011] The present invention aims to provide a luminescent layer material of a spiro structure, a preparation method thereof and an organic electroluminescent device, wherein the luminescent layer material is a compound having a structure as shown in formula (I), wherein the introduction of a Z group can improve the yield of the reaction in the preparation method, improve the chemical stability and thermal stability of the material, change the stacking mode of the molecules in the solid state, reduce the π-π stacking between molecules, thereby improving the luminous efficiency, inhibiting the efficiency roll-off and facilitating the service life of the OLED device. The luminescent layer material of the present invention includes a main material, a thermally activated delayed fluorescent material, a sensitizer material and a fluorescent luminescent material. The OLED device prepared with the main material of the present invention can significantly reduce the driving voltage and improve the stability of the device. The OLED device prepared using the TADF luminescent material and the sensitizer material of the present invention performs well in terms of efficiency roll-off, greatly improving the efficiency and stability of the device. In addition, the OLED device prepared using the fluorescent luminescent material of the present invention exhibits excellent stability and high color purity.

[0012] Solutions for solving problems

[0013] In a first aspect, the present invention provides a compound having a structure shown in formula (I):

[0014]

[0015] in,

[0016] X 1 , X 2 , X 3 Each independently represents -P(R 15 ) 3 -、-C(R 15 )(R 16 )-、-N(R 15 )-、-Bi(R 15 )-、-B(R 15 )-、-Si(R 15 )(R 16 )-、-Ge(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-C(=O)-、-P(R 15 )-、-P(=O)(R 15 )-or a single bond or not present; when X 1 , X 2 , X 3 When at least one of is absent, the carbon atom to which it is attached is terminated with hydrogen;

[0017] R 1 -R 14And each R 15 , R 16 Each independently represents hydrogen, deuterium, a halogen atom, optionally replaced by one or more R 20 Substituted C 1 -C 15 Alkyl or optionally with one or more R 20 Substituted C 6 -C 20 Aryl;

[0018] Z represents a halogen atom, optionally replaced by one or more R 20 Substituted C 1 -C 15 Alkyl, optionally with one or more R 20 Substituted C 1 -C 15 haloalkyl, optionally substituted with one or more R 20 Substituted C 1 -C 15 Alkoxy, optionally with one or more R 20 Substituted-N(R 17 )(R 18 ), optionally with one or more R 20 Substituted -Si(R 17 )(R 18 )(R 19 ), optionally with one or more R 20 Substituted -P(=O)(R 17 )(R 18 ), optionally with one or more R 20 Substituted C 6 -C 40 Aryl or optionally one or more R 20 substituted 5-40 membered heteroaryl;

[0019] Every R 17 , R 18 , R 19 Each independently represents hydrogen, C 1 -C 15 Alkyl, C 6 -C 40 Aryl or 5-40 membered heteroaryl;

[0020] L 1 , L 2 Each independently represents a single bond, optionally replaced by one or more R 20 Substituted C 6 -C 40 Aryl or optionally one or more R 20 substituted 5-40 membered heteroaryl;

[0021] A1 , A 2 Each independently represents optionally one or more R 20 Substituted with the following groups: C 6 -C 40 Aryl, 5-40 membered heteroaryl, -S(=O) 2 (R 21 )、-C(=O)(R 21 )、-N(R 21 )(R 22 )、-B(R 21 )(R 22 )、-P(=O)(R 21 )(R 22 ) or -Si(R 21 )(R 22 )(R 23 );

[0022] Every R 20 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, optionally with one or more R 24 Substituted C 6 -C 40 Aryl, optionally substituted with one or more R 24 substituted 5-40 membered heteroaryl, optionally substituted with one or more R 24 Substituted-N(R 21 )(R 22 ), optionally with one or more R 24 Substituted -Si(R 21 )(R 22 )(R 23 ) or optionally one or more R 24 Substituted -P(=O)(R 21 )(R 22 );

[0023] Every R 21 , R 22 , R 23 Each independently represents C 6 -C 40 Aryl or 5-40 membered heteroaryl;

[0024] Every R 24 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, C 6 -C 40 Aryl or 5-40 membered heteroaryl.

[0025] In some embodiments, X 1 , X 2 , X 3 Each independently represents -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-P(R 15 )-or a single bond or not present; when X 1 , X 2 , X 3 When at least one of is absent, the carbon atom to which it is attached is terminated with hydrogen;

[0026] Every R 15 , R 16 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl; preferably, each R 15 , R 16 Each independently represents C 1 -C 5 Alkyl or C 6 -C 10 Aryl; More preferably, each R 15 , R 16 Each independently represents a methyl group or a phenyl group.

[0027] In some embodiments, the compound of the present invention has a structure shown in formula (I'):

[0028]

[0029] Among them, X 1 , X 2 , X 3 , R 7 , R 10 , R 13 , Z, L 1 , L 2 , A 1 , A 2has the same meaning as described in formula (I).

[0030] In some embodiments, the compound of the present invention has a structure shown in formula (I-1):

[0031]

[0032] in,

[0033] X 3 Indicates -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-P(R 15 )- or a single bond; each R 15 , R 16 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl; preferably, each R 15 , R 16 Each independently represents C 1 -C 5 Alkyl or C 6 -C 10 Aryl; More preferably, each R 15 , R 16 each independently represents a methyl group or a phenyl group;

[0034] R 1 -R 14 , Z, L 1 , L 2 , A 1 , A 2 has the same meaning as described in formula (I).

[0035] In some embodiments, the compound of the present invention has a structure shown in formula (I'-1):

[0036]

[0037] Among them, X 3 , R 7 , R 10 , R 13 , Z, L 1 , L 2 , A 1 , A 2 has the same meaning as described in formula (I-1).

[0038] In some embodiments, the compound of the present invention has a structure shown in formula (I-2):

[0039]

[0040] in,

[0041] X 2 , X 3 Each independently represents -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-P(R 15 )- or a single bond; each R 15 , R 16 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl; preferably, each R 15 , R 16 Each independently represents C 1 -C 5 Alkyl or C 6 -C 10 Aryl; More preferably, each R 15 , R 16 each independently represents a methyl group or a phenyl group;

[0042] R 1 -R 14 , Z, L 1 , L 2 , A 1 , A 2 has the same meaning as described in formula (I).

[0043] In some embodiments, the compound of the present invention has a structure shown in formula (I'-2):

[0044]

[0045] Among them, X 2 , X 3 , R 7 , R 10 , R 13 , Z, L 1 , L 2 , A 1 , A 2 has the same definition as described in formula (I-2).

[0046] In some embodiments, the compound of the present invention has a structure shown in formula (I-3):

[0047]

[0048] in,

[0049] X 1 , X 2 , X 3 Each independently represents -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-P(R 15 )- or a single bond; each R 15 , R 16 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl; preferably, each R 15 , R 16 Each independently represents C 1 -C 5 Alkyl or C 6 -C 10 Aryl; More preferably, each R 15 , R 16 each independently represents a methyl group or a phenyl group;

[0050] R 1 -R 14 , Z, L 1 , L 2 , A 1 , A 2 has the same meaning as described in formula (I).

[0051] In some embodiments, the compound of the present invention has a structure shown in formula (I'-3):

[0052]

[0053] Among them, X 1 , X 2 , X 3 , R 7 , R 10 , R 13 , Z, L 1 , L 2 , A1 , A 2 has the same definition as described in formula (I-3).

[0054] In some embodiments, Z represents a halogen atom, C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, optionally with one or more R 20 Substituted-N(R 17 )(R 18 ), optionally with one or more R 20 Substituted -Si(R 17 )(R 18 )(R 19 ), optionally with one or more R 20 Substituted -P(=O)(R 17 )(R 18 ), optionally with one or more R 20 Substituted C 6 -C 20 Aryl or optionally one or more R 20 substituted 5-20 membered heteroaryl;

[0055] Every R 17 , R 18 , R 19 Each independently represents C 1 -C 15 Alkyl, C 6 -C 20 Aryl or 5-20 membered heteroaryl;

[0056] Every R 20 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, optionally with one or more R 24 Substituted C 6 -C 20 Aryl, optionally substituted with one or more R 24 substituted 5-20 membered heteroaryl, optionally substituted with one or more R 24 Substituted-N(R 21 )(R 22 ), optionally with one or more R 24 Substituted -Si(R 21 )(R22 )(R 23 ) or optionally one or more R 24 Substituted -P(=O)(R 21 )(R 22 );

[0057] Every R 21 , R 22 , R 23 Each independently represents C 6 -C 20 Aryl or 5-20 membered heteroaryl;

[0058] Every R 24 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, C 6 -C 20 Aryl or 5-20 membered heteroaryl.

[0059] In some preferred embodiments, Z represents a halogen atom, methyl, ethyl, isopropyl, tert-butyl, trifluoromethyl, cyano, methoxy, -N(CH 3 ) 2 、-Si(CH 3 ) 3 or any of the following groups:

[0060]

[0061] In some more preferred embodiments, Z represents F, methyl, ethyl, isopropyl, tert-butyl, methoxy, -N(CH 3 ) 2 、-Si(CH 3 ) 3 or any of the following groups:

[0062]

[0063] In the above Z groups:

[0064] Dashed lines indicate binding bonds;

[0065] Every R a -R r Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C 15 Alkyl, C 1 -C15 Haloalkyl, C 1 -C 15 Alkoxy, C 6 -C 20 Aryl or 5-20 membered heteroaryl, preferably hydrogen, cyano, C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 6 -C 20 Aryl or 5-20 membered heteroaryl, more preferably hydrogen, cyano, C 1 -C 5 Alkyl, C 1 -C 5 Haloalkyl, C 6 -C 10 The aryl group or the 5-20-membered heteroaryl group is more preferably hydrogen, cyano, trifluoromethyl, methyl, tert-butyl, phenyl or carbazolyl.

[0066] In some embodiments, -L 1 -A 1 , -L 2 -A 2 Each independently represents the following groups:

[0067]

[0068]

[0069] Preferably, -L 1 -A 1 , -L 2 -A 2 Each independently represents the following groups:

[0070]

[0071] With the above-L 1 -A 1 , -L 2 -A 2 The compound of the group can be used as the host material in the light-emitting layer. 1 -A 1 , -L 2 -A 2 Each independently represents the following groups:

[0072]

[0073] Preferably, -L 1 -A 1 , -L 2 -A 2Each independently represents the following groups:

[0074]

[0075] With the above-L 1 -A 1 , -L 2 -A 2 The compound of the group can be used as a TADF material or a sensitizing material in the light-emitting layer. 1 -A 1 , -L 2 -A 2 Each independently represents the following groups:

[0076]

[0077] Preferably, -L 1 -A 1 , -L 2 -A 2 Each independently represents the following groups:

[0078]

[0079] With the above-L 1 -A 1 , -L 2 -A 2 The compound with this structure can be used as a fluorescent light-emitting material in the light-emitting layer.

[0080] In the above-L 1 -A 1 , -L 2 -A 2 In the group:

[0081] Dashed lines indicate binding bonds;

[0082] Every R a -R v Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 1 -C 15 Alkoxy, C 6 -C 20 Aryl or 5-20 membered heteroaryl, preferably hydrogen, cyano, C 1 -C 15 Alkyl, C 1 -C 15 Haloalkyl, C 6 -C 20Aryl or 5-20 membered heteroaryl, more preferably hydrogen, cyano, C 1 -C 5 Alkyl, C 1 -C 5 Haloalkyl, C 6 -C 10 The aryl group or the 5-20-membered heteroaryl group is more preferably hydrogen, cyano, trifluoromethyl, methyl, tert-butyl, phenyl or carbazolyl.

[0083] In some embodiments, L 1 , L 2 Each independently represents a single bond or C 6 -C 20 Aryl, preferably a single bond or C 6 -C 10 Aryl, more preferably a single bond or phenyl.

[0084] In some embodiments, R 1 -R 14 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl.

[0085] In some preferred embodiments, R 1 -R 6 , R 8 -R 9 , R 11 -R 12 , R 14 Represents hydrogen, R 7 , R 10 , R 13 Each independently represents hydrogen, C 1 -C 15 Alkyl or C 6 -C 20 Aryl.

[0086] In some more preferred embodiments, R 7 , R 10 , R 13 Each independently represents hydrogen, C 1 -C 5 Alkyl or C 6 -C 10 Aryl.

[0087] In some further preferred embodiments, R 7 , R 10 , R 13 Each independently represents hydrogen, methyl or phenyl.

[0088] In a second aspect, the present invention provides the following compounds:

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] In a third aspect, the present invention provides a method for preparing the compound according to the first aspect or the second aspect, comprising the following steps:

[0118]

[0119] Step S1: reacting a compound having a structure of formula (A) with a compound having a structure of formula (B) to generate a compound having a structure of formula (C);

[0120] Step S2: reacting a compound having a structure of formula (C) to generate a compound having a structure of formula (D);

[0121] Step S3: reacting a compound having a structure of formula (D) to generate a compound having a structure of formula (E);

[0122] Step S4: reacting a compound having a structure of formula (E) with a compound having a structure of formula (F) to generate a compound having a structure of formula (I);

[0123] in,

[0124] M 1 、M 2 、M 3 and M 4 Each independently represents F, Cl, Br or I;

[0125] R 25 Represents C 1 -C 10 alkyl;

[0126] Y represents hydrogen, deuterium, a halogen atom or -B(OR 26 )(OR 27 ); or, R 26 and R 27 interconnected, and together with B and O atoms form a ring structure (e.g. );

[0127] R 26 and R 27 Each independently represents hydrogen, deuterium or C 1 -C 10 alkyl;

[0128] X 3 Indicates -C(R 15)(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O) 2 -、-P(R 15 )- or single bond;

[0129] R 1 ~R 16 , Z, X 1 , X 2 , A 1 , A 2 , L 1 and L 2 The compound having the definition described in the first aspect or having the structure of formula (I) is the compound described in the second aspect.

[0130] In some embodiments, if X 3 is a single bond, and the reaction in step S1 is carried out in the presence of a catalyst tetrakis(triphenylphosphine)palladium (Pd(Ph 3 ) 4 ) and potassium carbonate (K 2 CO 3 ) in the presence of 3 is not a single bond, then the reaction in step S1 is carried out in cesium carbonate (Cs 2 CO 3 ) in the presence of ).

[0131] In some embodiments, the reaction in step S2 is carried out in methanesulfonic acid (CH 3 SO 3 H).

[0132] In some embodiments, the reaction in step S3 is carried out in the presence of palladium acetate (Pd(OAc) 2 ), tri-tert-butylphosphine tetrafluoroborate (t-Bu 3 PHB 4 ) and sodium tert-butoxide (t-BuONa).

[0133] In some embodiments, the reaction in step S4 is performed in the presence of n-butyllithium (n-BuLi), glacial acetic acid (HOAc) and concentrated hydrochloric acid (HCl).

[0134] In some embodiments, different compounds having the structure of formula (I) can be transformed, for example, compound 1-15 is reacted with carbazole to generate compound 1-11.

[0135] In a fourth aspect, the present invention provides an organic electroluminescent device, which comprises, from bottom to top, a substrate, a first electrode, an organic functional material layer and a second electrode, wherein the organic functional material layer comprises a light-emitting layer; and the light-emitting layer comprises the compounds described in the first aspect and the second aspect.

[0136] In some embodiments, the organic functional material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0137] In some embodiments, the light-emitting layer includes a host material and a dopant material, wherein the host material and / or the dopant material comprises the compound described in the first aspect and the second aspect.

[0138] In some embodiments, the organic electroluminescent device is a thermally activated sensitized fluorescent organic electroluminescent device.

[0139] In a fifth aspect, the present invention provides a display device, comprising the organic electroluminescent device described in the fourth aspect.

[0140] Effects of the Invention

[0141] The technical effects of the present invention are embodied in the following aspects:

[0142] (1) Multiple donors and acceptors are connected to a rigid spirocyclic linker

[0143] The light-emitting layer material of the present invention enables multiple donors and acceptors to be connected to a rigid spirocyclic linker, which greatly enhances the rigidity of the molecule, which can not only effectively suppress the structural relaxation of the entire molecule, but also enhance the interaction between the donors and acceptors, thereby showing a higher external quantum efficiency and a lower efficiency roll-off. The maximum EQE of the light-emitting device prepared based on the compound of the present invention is generally greater than 30%. Limited by the molecular skeleton structure, the compound acceptor-donor-acceptor groups in the present invention are arranged approximately in parallel in space, forming a "sandwich"-like molecular structure, which enhances the spatial Coulomb interaction between the donors and acceptors, inhibits the non-radiative transition process, and thus improves the PLQY of the material. The introduction of multiple acceptors changes the properties of the molecular excited state, which is conducive to the formation of multiple nearly degenerate orbits, thereby promoting the formation of a RISC process with a "multi-channel" effect and reducing the efficiency roll-off of the device at high brightness, thereby achieving a stable and efficient electroluminescent device.

[0144] (2) Introduction of Z group

[0145] The introduction of the Z group inhibits the generation of isomers during chemical synthesis, greatly improves the reaction yield in the preparation method, reduces the difficulty of reaction purification and the cost of materials, and is conducive to industrial production and application. Figure 3As shown, when a Z group occupies one of the reactive sites, a product with a unique configuration can be obtained. This not only improves the yield of the reaction, but also reduces the difficulty of separation and purification, thereby greatly reducing the cost of production. Since the product generated in the present invention is single and has a very high yield (greater than 90%), the product is usually purified by recrystallization. This post-treatment method can shorten the time for product purification, reduce the loss of solvent, further reduce the production cost, and has a very high industrial application value.

[0146] Secondly, as a steric group, the Z group can reduce the π-π stacking between molecules of this type of compound, which is beneficial to suppress the reduction of luminescence efficiency caused by concentration quenching, thereby improving the device EQE and reducing the efficiency roll-off of the device. Single crystal data show that the introduction of the Z group can change the stacking state of molecules in the aggregated state, reduce the π-π stacking between molecules, and improve the efficiency of the luminescent material.

[0147] At the same time, the introduction of the Z group further improves the thermal stability and chemical stability of the light-emitting molecule, thereby ensuring the operational stability of the light-emitting device.

[0148] (3) As TADF material or sensitizing material

[0149] The organic light-emitting diode device prepared with the compound of the present invention not only exhibits excellent thermally activated delayed fluorescence characteristics, but also maintains excellent luminous efficiency even under high doping concentration conditions. The above characteristics make the compound of the present invention an ideal choice for TADF materials or sensitizing materials, mainly because the compound of the present invention can significantly improve the utilization rate of triplet excitons, thereby improving the efficiency and stability of the device, thereby achieving a significant technical improvement over existing solutions. Using the compound of the present invention as a sensitizing material can significantly improve the stability of deep blue and blue sensitized devices, and has potential commercial value.

[0150] (4) As a fluorescent material

[0151] Since the inherent rigid structure of spiro compounds can effectively inhibit the fluorescence quenching effect caused by intermolecular interactions, they are also suitable as building blocks of fluorescent materials. Therefore, the EQE of OLEDs devices prepared using the materials in the present invention as luminescent materials is generally high (generally greater than 30%), and can maintain a relatively high EQE at high brightness, indicating that using the materials in the present invention as fluorescent luminescent materials can significantly improve the efficiency of the device and reduce the efficiency roll-off of the device.

[0152] (5) As main material

[0153] The spirocyclic compound involved in the present invention has suitable singlet, triplet and molecular orbital energy levels as the main material, and its unique non-planar spiro conjugation effect, vertical orthogonal conformation and steric hindrance effect can effectively improve the photoelectric performance and stability of organic semiconductor materials.

[0154] (6) Economic security

[0155] The present invention selects low-toxic and easily available aromatic esters as initial raw materials, which can reduce the synthesis cost of materials and improve experimental safety.

[0156] In summary, the light-emitting layer material in the present invention has a large PLQY and RISC rate, thereby achieving a high EQE (generally greater than 30%) and a small device efficiency roll-off, and significantly extending the service life of the device, while also having excellent thermal stability and chemical stability. Based on the above advantages, the material with TADF effect in the present invention can be used as a sensitizer, and since most of the materials in the present invention are dark blue or blue thermally activated delayed fluorescent materials, they can effectively sensitize dark blue and blue light-emitting materials, thereby improving the device efficiency and stability of dark blue / blue light materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0157] Figure 1 The schematic diagram shows that the compound in CN 111635391 A easily produces isomers.

[0158] Figure 2 It is the degree of polarity proximity of isomers on thin layer chromatography silica gel plates.

[0159] Figure 3 The schematic diagram of the principle of the Z group in the present invention to improve the yield of the reaction intermediate.

[0160] Figure 4 This is a simplified diagram of the layer structure of an OLED device according to an embodiment of the present invention; wherein 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents an electron blocking layer, 6 represents a light-emitting layer, 7 represents a hole blocking layer, 8 represents an electron transport layer, 9 represents an electron injection layer, and 10 represents a cathode.

[0161] Figure 5 This is the stacking state of compound 2-45 in the aggregated state; the black balls represent nitrogen atoms, the gray balls represent carbon atoms, and the hydrogen atoms are not displayed.

[0162] Figure 6 Room temperature fluorescence spectra of compounds 1-1, 1-3, 1-11, 1-70, 2-1, 2-36, 2-182, 1-5, 1-15, 1-43, 2-3, 2-154, 2-203, and 3-8 measured in toluene.

[0163] Figure 7 This is the spectrum of compounds 1-1 and 2-36 in toluene at 77K.

[0164] Figure 8 For compound 1-1 1 H NMR spectrum.

[0165] Fig. 9 is the mass spectrum of compound 1-1.

[0166] Fig.10 This is the thermogravimetric analysis curve of compound 1-1. DETAILED DESCRIPTION

[0167] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0168] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0169] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0170] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0171] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0172] [Definition of terms]

[0173] In the present invention, a numerical range expressed using "a numerical value A to a numerical value B" means a range including the numerical values ​​A and B at the end points.

[0174] In the present invention, when "normal temperature" or "room temperature" is used, the temperature may be 15°C to 30°C, further 15°C to 25°C, for example 20°C.

[0175] <Halogen atom>

[0176] In the present invention, the "halogen atom" means fluorine, chlorine, bromine or iodine, particularly fluorine, chlorine or bromine.

[0177] <Alkyl>

[0178] In the present invention, "alkyl" refers to a monovalent saturated aliphatic hydrocarbon group, which can be a straight chain group or a branched chain group. The alkyl group in the present invention can be "C 1 -C 20 Alkyl", "C 1 -C 15 Alkyl", "C 1 -C 10 Alkyl", "C 1 -C 5 Alkyl" or "C 1 -C 3 "Alkyl" means that the group is an alkyl group, and the number of carbon atoms in the carbon chain is between 1-20, 1-15, 1-10, 1-5 or 1-3. The alkyl group in the present invention can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, n-hexyl, n-heptyl, n-octyl, etc.

[0179] <Haloalkyl>

[0180] In the present invention, "haloalkyl" refers to an alkyl group defined above in which one, two or more hydrogen atoms are replaced by halogen atoms. Representative examples of haloalkyl groups include -CCl 3 , -CF 3 , -CHCl 2 , CH 2 Cl, CH 2 Br, CH 2 I. -CH 2 CF 3 , -CF 2 CF 3 wait.

[0181] <Alkoxy>

[0182] In the present invention, "alkoxy" refers to -O-alkyl, the alkyl being as defined above. Preferably, the alkoxy has 1 to 15 carbon atoms, preferably 1 to 5 carbon atoms. Representative examples include methoxy, ethoxy, propoxy, tert-butoxy, pentyloxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, etc.

[0183] <Aryl>

[0184] In the present invention, "aryl" refers to a group containing 6 to 40 carbon atoms (C 6 -C 40 Aryl), or 6-30 carbon atoms (C 6 -C 30 Aryl), or 6-20 carbon atoms (C 6 -C 20 Aryl), or 6-18 carbon atoms (C 6 -C 18 Aryl), or 6-12 carbon atoms (C 6 -C 12 Aryl), or 6-10 carbon atoms (C 6 -C 10 The term "aryl" can be used interchangeably with the term "aromatic ring". Examples of aryl groups can include phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, fluorenyl, spirobifluorenyl, etc. The aryl group in the present invention can be a carbocyclic ring system obtained by condensing an aromatic ring and an aliphatic ring, wherein the carbon atoms on the aliphatic ring can be optionally oxidized. For example, the aryl group of the present invention can be: wait.

[0185] <Heteroaryl>

[0186] In the present invention, "heteroaryl" refers to an aromatic monocyclic or polycyclic ring system containing a 5-40 membered structure (5-40 membered heteroaryl), or a 5-30 membered structure (5-30 membered heteroaryl), or a 5-20 membered structure (5-20 membered heteroaryl), or a 5-18 membered structure (5-18 membered heteroaryl), or a 5-12 membered structure (5-12 membered heteroaryl), or a 5-10 membered structure (5-10 membered heteroaryl), or a 5-6 membered structure (5-6 membered heteroaryl), wherein at least one ring atom is a heteroatom and the remaining atoms are carbon, and the heteroatoms are independently selected from N, O, S, Se, Te, B or P, and the number of heteroatoms is preferably 1, 2 or 3. The term "heteroaryl" can be used interchangeably with the term "heteroaromatic ring". Examples of heteroaryl groups include carbazolyl, furanyl, thienyl, oxazolyl, thiazolyl, isoxazolyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, quinolyl, isoquinolyl, pteridinyl, purinyl, indolyl, isoindolyl, indazolyl, benzofuranyl, benzothienyl, benzopyridinyl, benzopyrimidinyl, benzopyrazinyl, benzimidazolyl, and the like.

[0187] The heteroaryl group in the present invention can be a carbocyclic ring system obtained by fusion of an aromatic ring or a heteroaromatic ring and an aliphatic ring; wherein, when the aromatic ring and the aliphatic ring are fused, at least one ring atom of the aliphatic ring is a heteroatom and the remaining atoms are carbon, the heteroatoms are independently selected from N, O, S, Se, Te, B or P, and the number of heteroatoms is preferably 1, 2 or 3; when the heteroaromatic ring and the aliphatic ring are fused, the ring atoms of the aliphatic ring can all be carbon atoms or at least one ring atom is a heteroatom and the remaining atoms are carbon, the heteroatoms are independently selected from N, O, S, Se, Te, B or P, and the number of heteroatoms is preferably 1, 2 or 3. The carbon atoms or heteroatoms on the above-mentioned aliphatic ring can be optionally oxidized. For example, the heteroaryl group of the present invention can be:

[0188]

[0189] wait.

[0190] [Organic electroluminescent device]

[0191] The organic electroluminescent device of the present invention comprises a substrate, a first electrode, an organic functional material layer and a second electrode in order from bottom to top, wherein the organic functional material layer comprises a light-emitting layer; and the light-emitting layer contains the compound of the present invention.

[0192] Preferably, the organic functional material layer further comprises at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer.

[0193] Preferably, the light-emitting layer comprises a host material and a dopant material, wherein the host material and / or the dopant material comprises the compound of the present invention.

[0194] The compound of the present invention can be used as a sensitizing material. Therefore, in some embodiments, the organic electroluminescent device of the present invention can be a thermally activated sensitized fluorescent organic electroluminescent device.

[0195] Figure 4 2 is a diagram showing the structure of the organic electroluminescent device of the present invention. Figure 5 As shown, in the organic electroluminescent device of the present invention, for example, an anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9 and a cathode 10 are sequentially arranged on a substrate 1.

[0196] The organic electroluminescent device of the present invention is not limited to such a structure. For example, in the multilayer structure, some organic functional material layers can be omitted. For example, the hole injection layer 3 between the anode 2 and the hole transport layer 4, the electron blocking layer 5 between the hole transport layer 4 and the light-emitting layer 6, the hole blocking layer 7 between the light-emitting layer 6 and the electron transport layer 8, and the electron injection layer 9 between the electron transport layer 8 and the cathode 10 can be omitted, and the anode 2, the hole transport layer 4, the light-emitting layer 6, the electron transport layer 8 and the cathode 10 are sequentially arranged on the substrate 1.

[0197] The organic electroluminescent device according to the present invention can be manufactured by materials and methods known in the art except that the above-mentioned organic functional material layer includes the compound represented by the above-mentioned formula (I). In addition, when the above-mentioned organic electroluminescent device includes multiple organic functional material layers, the above-mentioned organic functional material layers can be formed by the same substance or different substances.

[0198] For example, the organic electroluminescent device according to the present invention can be manufactured by sequentially stacking a first electrode, an organic layer, and a second electrode on a substrate. In this case, it can be manufactured as follows: a PVD (physical vapor deposition) method such as a sputtering method or an electron beam evaporation method is used to vapor-deposit a metal or a conductive metal oxide or an alloy thereof on a substrate to form an anode, and then an organic functional material layer including a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer is formed on the anode, and then a substance that can be used as a cathode is vapor-deposited on the organic layer. However, the manufacturing method is not limited thereto.

[0199] As an example, the first electrode is an anode and the second electrode is a cathode, or the first electrode is a cathode and the second electrode is an anode.

[0200] Preferably, the anode comprises a metal, a metal oxide, or a conductive polymer. For example, the anode may have a work function in the range of about 3.5 to 5.5 eV. Illustrative examples of conductive materials for the anode include carbon, aluminum, vanadium, chromium, copper, zinc, silver, gold, other metals and alloys thereof; zinc oxide, sodium oxide, tin oxide, sodium tin oxide (ITO), sodium zinc oxide, and other similar metal oxides; and mixtures of oxides and metals, such as ZnO:Al and SnO 2 : Sb. Both transparent materials and non-transparent materials can be used as anode materials. For a structure that emits light to the anode, a transparent anode can be formed. In this article, transparency means the degree to which light emitted from the organic material layer is permeable, and the transmittance of light is not particularly limited.

[0201] For example, when the organic light-emitting device of the present specification is a top emission type, and the anode is formed on the substrate before the organic material layer and the cathode are formed, not only transparent materials but also non-transparent materials with excellent light reflectivity can be used as the anode material. Alternatively, when the organic light-emitting device of the present specification is a bottom emission type, and the anode is formed on the substrate before the organic material layer and the cathode are formed, a transparent material is required as the anode material, or the non-transparent material needs to be formed into a thin film thin enough to be transparent.

[0202] Preferably, as for the cathode, a material having a small work function is preferred as the cathode material so that electron injection can be easily performed. For example, in the present specification, a material having a work function ranging from 2eV to 5eV can be used as the cathode material. The cathode may include a metal such as magnesium, calcium, sodium, potassium, titanium, steel, tin, lithium, zinc, aluminum, silver, tin and lead or an alloy thereof; a material having a multilayer structure such as LiF / Al or LiO 2 / Al, etc., but not limited to these.

[0203] The cathode may be formed using the same material as the anode. In this case, the cathode may be formed using the anode material as described above. In addition, the cathode or the anode may include a transparent material.

[0204] Depending on the materials used, the organic light emitting device of the present invention may be a top emission type, a bottom emission type or a two-side emission type. Preferably, the organic light emitting device of the present invention comprises a hole injection layer. The hole injection layer may preferably be placed between the anode and the light emitting layer. The hole injection layer is formed by a hole injection material known to those skilled in the art. The hole injection material is a material that easily receives holes from the anode at a low voltage, and the HOMO of the hole injection material is preferably located between the work function of the anode material and the HOMO of the surrounding organic material layer. Specific examples of hole injection materials include, but are not limited to, metal porphyrin organic materials, oligothiophene organic materials, aromatic amine organic materials, hexanitrile hexaazatriphenylene organic materials, quinacridone organic materials, perylene organic materials, anthracenequinone conductive polymers, polyaniline conductive polymers or polythiophene conductive polymers, etc.

[0205] Preferably, the organic light-emitting device of the present invention comprises a hole transport layer. The hole transport layer may preferably be placed between the hole injection layer and the light-emitting layer, or between the anode and the light-emitting layer. The hole transport layer is formed of a hole transport material known to those skilled in the art. The hole transport material is preferably a material with high hole mobility, which can transfer holes from the anode or the hole injection layer to the light-emitting layer. Specific examples of hole transport materials include, but are not limited to, aromatic amine organic materials, conductive polymers, and block copolymers having a bonding portion and a non-bonding portion.

[0206] Preferably, the organic light-emitting device of the present invention further comprises an electron blocking layer. The electron blocking layer may preferably be disposed between the hole transport layer and the light-emitting layer, or between the hole injection layer and the light-emitting layer, or between the anode and the light-emitting layer. The electron blocking layer is formed of an electron blocking material known to those skilled in the art, such as TCTA.

[0207] Preferably, the organic light-emitting device of the present invention comprises an electron injection layer. The electron injection layer may preferably be placed between the cathode and the light-emitting layer. The electron injection layer is formed of an electron injection material known to those skilled in the art. The electron injection layer may be formed using, for example, an electron-accepting organic compound. Here, as an electron-accepting organic compound, known optional compounds may be used without particular limitation. As such organic compounds, polycyclic compounds may be used: polycyclic compounds, such as terphenyl or quaterphenyl or derivatives thereof; polycyclic hydrocarbon compounds, such as naphthalene, tetracene, perylene, hexaphenylene, chrysene, anthracene, diphenylanthracene or phenanthrene, or derivatives thereof; or heterocyclic compounds, such as phenanthroline, phenanthridine or derivatives thereof. Inorganic substances may also be used to form, including, but not limited to, magnesium, calcium, sodium, potassium, aluminum, silver, tin and lead or alloys thereof; LiF, LiO 2 、LiCoO 2 、NaCl、MgF 2 , CsF, CaF 2 , BaF2 、NaF、RbF、CsCl、Ru 2 CO 3 , YbF 3 etc.; and materials with multilayer structures, such as LiF / Al or LiO 2 / Al et al.

[0208] Preferably, the organic light-emitting device of the present invention comprises an electron transport layer. The electron transport layer may preferably be placed between the electron injection layer and the light-emitting layer, or between the cathode and the light-emitting layer. The electron transport layer is formed of an electron transport material known to those skilled in the art. The electron transport material is a material that can easily receive electrons from the cathode and transfer the received electrons to the light-emitting layer. Preferably, a material with high electron mobility is used. Specific examples of electron transport materials include, but are not limited to, 8-hydroxyquinoline aluminum complexes; complexes containing 8-hydroxyquinoline aluminum; organic free radical compounds; and hydroxyflavone metal complexes; and TPBi.

[0209] Preferably, the organic light-emitting device of the present invention further comprises a hole blocking layer. The hole blocking layer may preferably be placed between the electron transport layer and the light-emitting layer, or between the electron injection layer and the light-emitting layer, or between the cathode and the light-emitting layer. The hole blocking layer is a layer that prevents the injected holes from passing through the light-emitting layer to reach the cathode, and can generally be formed under the same conditions as the hole injection layer. Specific examples thereof include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, BCP, aluminum complexes, etc., but are not limited thereto.

[0210] Preferably, the hole blocking layer and the electron transport layer are the same layer. In addition, preferably, the organic light-emitting device may further include a substrate. Specifically, in the organic light-emitting device, the anode or the cathode may be provided on the substrate. There is no particular limitation on the substrate. The substrate may be a rigid substrate, such as a glass substrate, or a flexible substrate, such as a flexible film-shaped glass substrate, a plastic substrate or a film-shaped substrate.

[0211] The organic light-emitting device of the present invention can be produced using the same materials and methods known in the art. Specifically, the organic light-emitting device can be produced by the following steps: using a physical vapor deposition (PVD) method (such as sputtering or electron beam evaporation lock) to deposit a metal, a conductive metal oxide or an alloy thereof on a substrate to form an anode; forming an organic material layer including a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer and an electron transport layer on the anode; and then depositing a material that can be used to form a cathode thereon. In addition, an organic light-emitting device can also be manufactured by sequentially depositing a cathode material, one or more organic material layers and an anode material on a substrate. In addition, during the manufacture of an organic light-emitting device, in addition to the physical vapor deposition method, a solution coating method can also be used to make the organic light-emitting composite material of the present invention into an organic material layer. As used in this specification, the term "solution coating method" means spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying, etc., but is not limited thereto.

[0212] There is no specific limitation on the thickness of each layer, and those skilled in the art can determine it according to needs and specific circumstances. Preferably, the thickness of the light-emitting layer, the hole injection layer, the hole transport layer, the electron blocking layer, the electron transport layer and the electron injection layer is 0.5 to 150 nm, preferably 1 to 100 nm. More preferably, the thickness of the light-emitting layer is 10 to 80 nm, preferably 15 to 30 nm, for example 20 nm.

[0213] Example

[0214] The manufacture of the compound represented by the above general formula (I) and the organic electroluminescent device containing the same is specifically described in the following examples. However, the following examples are only used to illustrate the present invention, and the scope of the present invention is not limited thereto. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0215] Example 1 Synthesis of Compound 1-1

[0216] Synthesis of intermediate H1:

[0217]

[0218] Under nitrogen conditions, 2.4 g (10 mmol) 1-bromo-3-chlorobenzoic acid methyl ester, 1.38 g (20 mmol) anhydrous sodium carbonate, 1.7 g (10 mmol) 5-chloro-2-methylphenylboronic acid, 115.4 mg (0.1 mmol) tetrakis(triphenylphosphine)palladium and 100 mL mixed solvent (toluene: water: ethanol = 5: 1: 1 (volume ratio)) were added to a clean 250 mL three-necked flask in sequence, and the system was heated to 80 ° C for 6 hours. After the reaction was completed, the heating was stopped and the reaction system was cooled to room temperature by itself. The reaction solution was poured into about 200 mL of water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and further purified by column chromatography (350 mesh silica gel, eluent was petroleum ether: dichloromethane = 1: 1 (volume ratio)) to obtain a solid, namely intermediate H1 (2.2 g, yield 95.4%). MS(EI):m / z 280.01[M + ] Elemental analysis calculated value C 14 H 10 Cl 2 O 2 (%): C, 59.81; H, 3.59; Cl, ​​25.22; O, 11.38; Found: C, 59.88; H, 3.51; Cl, ​​25.21; O, 11.40.

[0219] Synthesis of intermediate M1:

[0220]

[0221] Under nitrogen, 2.5 g (8.47 mmol) of intermediate H1, 1.63 g (16.94 mmol) of methanesulfonic acid and 30 mL of toluene were added to a clean 100 mL three-necked flask in sequence, and the system was heated to 110°C for overnight reaction. After the reaction was completed, the heating was stopped, and the reaction system was cooled to room temperature by itself, distilled under reduced pressure, concentrated, and recrystallized from an ethanol solution to obtain a yellow solid, namely intermediate M1 (2.18 g, yield 97.82%). MS (EI): m / z 262.00 [M + ] Elemental analysis calculated value C 14 H 8 Cl 2 O(%): C, 63.91; H, 3.06; Cl, ​​26.95; O, 6.08; Found: C, 63.95; H, 3.06; Cl, ​​26.92; O, 6.07.

[0222] Synthesis of intermediate A1:

[0223]

[0224] Under nitrogen conditions, 2g (7.6mmol) of intermediate M1, 2.4g (30.4mmol) of sodium tert-butoxide, 78mg (0.3mmol) of palladium acetate, 0.15g (0.5mmol) of tri-tert-butylphosphine tetrafluoroborate, 6.62g (15.20mmol) of 2,4-diphenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine and 50mL of toluene were added to a clean 100mL three-necked flask in sequence, and the system was heated to 110°C to react overnight. After the reaction was completed, the heating was stopped, the reaction system was cooled to room temperature by itself, distilled under reduced pressure, concentrated, and recrystallized in ethanol solution to obtain a yellow solid, namely intermediate A1 (5.42g, yield 88.1%). MS (EI): m / z 808.3 [M + ] Elemental analysis calculated value C 56 H 36 N 6 O(%): C, 83.15; H, 4.49; N, 10.39; O, 1.98; Found: C, 83.10; H, 4.51; N, 10.38; O, 2.01.

[0225] Synthesis of compound 1-1:

[0226]

[0227] Under nitrogen protection, 2-bromotriphenylamine (1.89 g, 5.38 mmol) was placed in a 250 mL two-necked bottle, 60 mL of anhydrous tetrahydrofuran was added to dissolve, and then placed at -78 ° C, 2.40 mol / L n-butyl lithium solution (2.24 mL, 5.38 mmol) was added dropwise, and after stirring at -78 ° C for 1 hour, intermediate A1 (3.11 g, 3.84 mmol) was added, and after stirring overnight, 10 mL of distilled water was added to quench. The reaction solution was decompressed to remove tetrahydrofuran, 40 mL of ethyl acetate was added, and after extraction 3 times, ethyl acetate was removed under reduced pressure, ethanol was added, recrystallized, filtered, and the solid obtained after drying was placed in a 100 mL flask, 20 mL of acetic acid was added, and after stirring for 10 minutes, 3 mL of concentrated hydrochloric acid was added and heated to 110 ° C and refluxed for 3 hours. After the reaction was completed, the temperature was lowered to room temperature, and the reaction solution was poured into 500 mL of ice water. The product precipitated and was filtered off and subjected to silica gel column chromatography using a mixture of dichloromethane and petroleum ether as an eluent to obtain compound 1-1 (3.56 g, yield 87.1%). Fig. 9 ,MS(EI):m / z 1036.41[M + ] Elemental analysis calculated value C 74 H 49 N 7(%): C, 85.77; H, 4.77; N, 9.46; Found: C, 85.59; H, 4.83; N, 9.54. Compound 1-1 1 HNMR spectrum see Figure 8 The thermogravimetric analysis curve of compound 1-1 is shown in Fig.10 .

[0228] Example 2 Synthesis of Compound 2-36

[0229]

[0230] 0.82 g (2.51 mmol) of N-(2-bromophenyl)-3,6-dimethylcarbazole was added to a dried 100 mL two-necked flask, vacuumized and added with 20 mL of tetrahydrofuran, cooled at -78 °C for 5 minutes, then 1.6 mol / L n-butyl lithium reagent (1.85 mL, 2.51 mmol) was added, and the reaction was continued for one hour, and then a solution of intermediate A1 (2.0 g, 2.47 mmol) dissolved in tetrahydrofuran was added thereto, and the reaction was continued at room temperature for 2 hours. After 5 hours, water was added to quench, vacuum distillation was performed, the solvent was dried, and the dried solid was transferred to a dry 100 mL two-necked flask, 30 mL of acetic acid solution and 3 mL of concentrated hydrochloric acid were added, and the reaction was carried out at 110°C for 5 hours, and the pH was adjusted to about 8. The mixture was extracted with dichloromethane and vacuum distilled and concentrated, and further purified by column chromatography (300 mesh silica gel, eluent was petroleum ether: dichloromethane = 4:1 (volume ratio)) to obtain a yellow solid, namely compound 2-36 (2.24 g, yield 85.5%). MS (EI): m / z 1062.42 [M + ] Elemental analysis calculated value C 76 H 51 N 7 (%): C, 85.93; H, 4.84; N, 9.23; Measured value: C, 85.93; H, 4.87; N, 9.21.

[0231] The intermediate compounds in Table 1 were synthesized with reference to the synthesis methods of intermediate H1, intermediate M1, and intermediate A1, and the compounds in the examples in Table 2 were synthesized with reference to the synthesis methods of compound 1-1 in Example 1 and compound 2-36 in Example 2. Among them, the synthesis methods of Examples 8, 48, 52, and 61 also need to refer to Example 6:

[0232] Example 6 Synthesis of Compound 1-11

[0233]

[0234] Under nitrogen, add 1.5g (1.44mmol) of compound 1-15, 0.36g (2.16mmol) of carbazole, 0.94g (2.88mmol) of cesium carbonate and 60mL of dimethyl sulfoxide to a clean 100mL two-necked bottle, heat the system to reflux, and react overnight under reflux. After the reaction is complete, pour the reaction solution into about 100mL of water, filter it with suction, and further purify it by column chromatography (350 mesh silica gel, eluent is petroleum ether: dichloromethane = 4:1 (volume ratio)) to obtain a yellow solid, namely compound 1-11 (1.4g, yield 81.8%). MS (EI): m / z1186.45 [M + ] Elemental analysis calculated value C 85 H 54 N 8 (%): C, 85.98; H, 4.58; N, 9.44; Measured value: C, 85.68; H, 4.68; N, 9.64.

[0235] In addition, the synthesis methods of Examples 32, 53, and 54 refer to Example 31:

[0236] Example 31 Synthesis of Compound 1-91

[0237] Synthesis of intermediate H7:

[0238]

[0239] Under nitrogen, 5 g (14.67 mmol) methyl 1-bromo-6-iodobenzoate, 3.0 g (17.6 mmol) 5-chloro-2-methylphenylboronic acid, 0.15 g tetrakis(triphenylphosphine)palladium, 3.11 g (29.33 mmol) sodium carbonate and 40 mL of a mixture of toluene, ethanol and water (toluene: water: ethanol = 5: 1: 1 (volume ratio)) were added to a clean 100 mL three-necked flask in sequence, and the system was heated to 80°C for 6 hours. After the reaction was completed, the heating was stopped, and the reaction system was cooled to room temperature by itself, distilled under reduced pressure, concentrated, and further purified by column chromatography (300 mesh silica gel, eluent was petroleum ether: dichloromethane = 3: 1 (volume ratio)) to obtain a white solid, namely intermediate H7 (4.70 g, yield 94.37%). MS (EI): m / z 323.96 [M + ] Elemental analysis calculated value C 15 H 12 BrClO 2 (%): C, 53.05; H, 3.56; Br, 23.53; Cl, ​​10.44; O, 9.42; Found: C, 53.05; H, 3.56; Br, 23.51; Cl, ​​10.42; O, 9.45.

[0240] Synthesis of intermediate M7:

[0241]

[0242] Under nitrogen, 4.0 g (12.29 mmol) of intermediate H7, 3.54 g (36.86 mmol) of methanesulfonic acid and 30 mL of toluene were added to a clean 100 mL three-necked flask in sequence, and the system was heated to 110°C for overnight reaction. After the reaction was completed, the heating was stopped, and the reaction system was cooled to room temperature by itself, concentrated by vacuum distillation, and recrystallized from an ethanol solution to obtain a yellow solid, namely intermediate M7 (3.55 g, yield 94%). MS (EI): m / z 307.57 [M + ] Elemental analysis calculated value C 14 H 8 BrClO (%): C, 54.67; H, 2.62; Br, 25.98; Cl, ​​11.53; O, 5.20; Found: C, 54.63; H, 2.65; Br, 25.92; Cl, ​​11.51; O, 5.27.

[0243] Synthesis of intermediate A16:

[0244]

[0245] Under nitrogen, 1.5 g (4.88 mmol) of intermediate M7, 2.73 g (5.36 mmol) of intermediate N1, 0.15 g (0.24 mmol) of tetrakis(triphenylphosphine)palladium, 1.35 g (9.75 mmol) of potassium carbonate and 40 mL of a mixture of toluene, ethanol and water (toluene: water: ethanol = 5:1:1 (volume ratio)) were added to a clean 100 mL three-necked flask in sequence, and the system was heated to 80 °C for 6 hours. After the reaction was completed, the heating was stopped, and the reaction system was cooled to room temperature by itself, distilled under reduced pressure, concentrated, and further purified by column chromatography (300 mesh silica gel, eluent was petroleum ether: dichloromethane = 3:1 (volume ratio)) to obtain a yellow solid, namely intermediate A16 (2.72 g, yield 91.5%). MS (EI): m / z 608.23 [M + ] Elemental analysis calculated value C 40 H 34 BCO 3 (%): C, 78.89; H, 5.63; B, 1.78; Cl, ​​5.82; O, 7.88; Found: C, 78.49; H, 5.68; B, 1.88; Cl, ​​5.98; O, 7.98.

[0246] Synthesis of intermediate A17:

[0247]

[0248] Under nitrogen, 2.05 g (3.37 mmol) of intermediate A16, 0.65 g (6.73 mmol) of sodium tert-butoxide, 80 mg (0.35 mmol) of palladium acetate, 0.18 g (0.62 mmol) of tri-tert-butylphosphine tetrafluoroborate, 1.54 g (3.53 mmol) of 2,4-diphenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine and 50 mL of toluene were added to a clean 100 mL three-necked flask in sequence. After the reaction was completed, the heating was stopped, the reaction system was cooled to room temperature by itself, distilled under reduced pressure, concentrated, and further purified by column chromatography (350 mesh silica gel, eluent was petroleum ether: dichloromethane = 3:1 (volume ratio)) to obtain a yellow solid, namely intermediate A17 (3.35 g, yield 90.4%). MS(EI):m / z 881.38[M + ] Elemental analysis calculated value C 61 H 48 BN 3 O 3 (%): C, 83.08; H, 5.49; B, 1.23; N, 4.76; O, 5.44; Found: C, 82.08; H, 5.59; B, 1.28; N, 4.79; O, 5.64.

[0249] Synthesis of compound 1-91:

[0250]

[0251] 2-Bromotriphenylamine (0.88 g, 2.72 mmol) was added to a dried 100 mL two-necked flask, vacuumized and added with 20 mL of tetrahydrofuran, cooled at -78°C for 5 minutes, then 1.60 mL (2.72 mmol) of 1.6 mol / L n-butyllithium reagent was added, and the reaction was continued for one hour, and then a solution of intermediate A17 (2.0 g, 2.27 mmol) dissolved in tetrahydrofuran was added thereto, reacted at room temperature for 2 hours, quenched with water, distilled under reduced pressure, and the solvent was dried. The spin-dried solid was transferred to a dry 100 mL two-necked flask, and 30 mL of glacial acetic acid and 3 mL of concentrated hydrochloric acid were added. After reacting at 110°C for 5 hours, the pH was adjusted to about 8, and the organic matter in the aqueous solution was extracted with dichloromethane, and the solution was distilled under reduced pressure, concentrated, and further purified by column chromatography (300 mesh silica gel, eluent was petroleum ether: dichloromethane = 4:1 (volume ratio)) to obtain a yellow solid, namely compound 1-91 (2.17 g, yield 86.3%). MS (EI): m / z 1109.19 [M + ] Elemental analysis calculated value C 79 H 61 BN4 O 2 (%): C, 85.55; H, 5.54; B, 0.97; N, 5.05; O, 2.88; Measured value: C, 85.35; H, 5.58; B, 0.99; N, 5.04; O, 2.86.

[0252] Table 1

[0253]

[0254]

[0255]

[0256]

[0257]

[0258]

[0259]

[0260]

[0261] Table 2

[0262]

[0263]

[0264]

[0265]

[0266]

[0267]

[0268]

[0269]

[0270]

[0271] The hydrogen spectrum data of some compounds are shown in Table 3:

[0272] Table 3

[0273]

[0274]

[0275]

[0276] Example 95: Preparation of organic electroluminescent device 1 (organic EL device 1)

[0277] The process of preparing OLED devices by vacuum evaporation method: first, the indium tin oxide (ITO) conductive glass substrate is cleaned, and then the hole injection layer 3, the hole transport layer 4, the electron blocking layer 5, the light emitting layer 6, the hole blocking layer 7, the electron transport layer 8, the electron injection layer 9 and the cathode 10 are sequentially evaporated on the transparent anode 2 in the vacuum chamber, where 1 is a glass substrate, and the device structure diagram is shown in Figure 4 Finally, use UV curing glue to bond the OLED glass and glass cover or metal cover, so as to seal the organic layer and electrodes sandwiched between the cover and substrate, and isolate them from water, oxygen and dust from the outside. The specific operation steps are as follows:

[0278] The ITO glass substrate with a film thickness of 100 nm was first ultrasonically treated in Decon 90 alkaline cleaning solution, then rinsed in deionized water, and cleaned three times in acetone and ethanol. Then, it was baked in a clean environment until the moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to obtain a clean ITO glass substrate. The treated ITO glass substrate was placed in a vacuum chamber and evacuated to 4×10 -4 – 2×10 -5 Pa. Then, on the glass substrate with ITO electrode, The compound 4,4',4'-((1E, 1'E, 1'E)-cyclopropane-1,2,3-triylidene(cyanomethaneylidene))tris(2,3,5,6-tetrafluorobenzonitrile) (HIL1) and N-([1,1'-biphenyl]-2-yl)-2',7'-di-tert-butyl-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[fluorene]-2-amine (HTL1) were mixed by evaporation at a evaporation rate of 100 to form a hole injection layer with a film thickness of 10 nm. On the hole injection layer, HTL1 was evaporated at a rate of 100 nm to form a hole transport layer with a thickness of 30 nm. 9,9',9'-triphenyl-9H,9'H,9"H-3,3':6',3'-tricarbazole (Tris-PCz) was evaporated at a deposition rate of 1.5 to form an electron blocking layer with a thickness of 20 nm. On the electron blocking layer, the main material 3,3'-di(9H-carbazole-9-yl)-1,1'-biphenyl (mCBP) was evaporated at a deposition rate of The evaporation rate of compound 1-1 as a doping material is A 20 nm thick light-emitting layer was formed by dual-source co-evaporation, wherein the doping weight ratio of compound 1-1 was 15 wt %. 6,6'-((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(2,4-diphenyl-1,3,5-triazine) (CF3-TRZ) was evaporated at a deposition rate of 100 nm to form a hole blocking layer with a film thickness of 10 nm. A mixture of 70 wt% 1,3-bis(9-phenylbenzo[h]quinolin-2-yl)benzene (BPPB) and 30 wt% 8-hydroxyquinoline lithium (Liq) was deposited at a deposition rate of 1.5 wt% to form an electron transport layer with a film thickness of 40 nm. Liq was evaporated at a rate of 100 to form an electron injection layer with a film thickness of 2 nm. Aluminum was evaporated at the above evaporation rate to form a cathode with a film thickness of 100 nm, and finally the device was packaged.

[0279] Examples 96 to 166 and Comparative Examples 1 to 3: Preparation of Organic EL Devices 2 to 72 and Comparative Examples 1 to 3

[0280] Organic EL devices 2 to 72 were prepared under the same conditions as organic EL device 1, except that the compounds with TADF properties in the following Table 4 were used to replace the final light-emitting material in the light-emitting layer of Example 95, and 9-(3'-(9H-carbazole-9-yl)-5-cyano-[1,1'-biphenyl]-3-yl)-9H-carbazole-3-carbonitrile (mCBP-2CN) and 9,9'-(4-(triphenylsilyl)dibenzo[b,d]furan-2,8-diyl)bis(9H-carbazole) (BH2) were used to replace the main material in Example 95; comparative devices 1 to 3 were prepared using the reported DM-B, Ref.1 and Ref.2 materials instead of the final light-emitting material in Example 95, as shown in Table 4 for details.

[0281] Examples 167 to 175 and Comparative Examples 4 to 6: Preparation of Organic EL Devices 73 to 81 and Comparative Examples 4 to 6 (as Host Materials)

[0282] Except that the compounds in Table 5 are used instead of the main material in Example 95, and BL01, BL05, BDCz or v-DABNA is used instead of the light-emitting material in Example 95, organic EL devices 73 to 81 are prepared under the same conditions as organic EL device 1; mCBP or mCBP-2CN is used as the main material and BDCz or v-DABNA is used as the final light-emitting material to prepare comparative examples 4 to 6, and the details are shown in Table 5.

[0283] Example 176: Preparation of Organic EL Device 82 (Preparation of Sensitized Device)

[0284] The preparation method of the light-emitting layer is as follows: on the electron blocking layer, the evaporation rate of mCBP as the main material is The evaporation rates of the compounds BDCz and 1-1 as doping materials are The doping weight ratio of the compound BDCz is 1wt%, the doping weight ratio of the compound 1-1 is 20wt%, and a 20nm light-emitting layer is formed by three-source co-evaporation. The rest is the same as the preparation method of the organic EL device 1 in Example 95, see Table 6 for details.

[0285] Examples 177-178: Preparation of organic EL devices 83-84 (Preparation of sensitized devices)

[0286] In the light-emitting layer, mCBP-2CN and BH2 were used as the main materials respectively, and the rest were the same as the preparation method of the organic EL device 82 in Example 176. Details are shown in Table 6.

[0287] Example 179: Preparation of Organic EL Device 85 (Preparation of Sensitized Device)

[0288] The preparation method of the light-emitting layer is as follows: on the electron blocking layer, the evaporation rate of mCBP is Evaporation rates of compounds v-DABNA and 2-36 as doping materials The evaporation rate was 1000 to form a layer with a thickness of 20 nm as the light-emitting layer, the doping weight ratio of the compound v-DABNA was 1 wt %, and the doping weight ratio of the compound 2-36 was 20 wt %. The rest was the same as the preparation method of the organic EL device 1 in Example 95, and the details are shown in Table 6.

[0289] Example 180: Preparation of Organic EL Device 86 (Preparation of Sensitized Device)

[0290] The preparation method of the light-emitting layer is as follows: on the electron blocking layer, the evaporation rate of mCBP is Evaporation rates of compounds v-DABNA and 2-45 as doping materials The evaporation rate was 10000 and the evaporation was carried out to form a luminescent layer with a thickness of 20 nm. The doping weight ratio of the compound v-DABNA was 1 wt %, and the doping weight ratio of the compound 2-45 was 20 wt %. The rest was the same as the preparation method of the organic EL device 1 in Example 95. The details are shown in Table 6.

[0291] Examples 181-182 and Comparative Examples 7-8: Preparation of Organic EL Devices 87-88 and Comparative Examples 7-8 (Preparation of Sensitized Devices)

[0292] Except for using BL01 and BL05 to replace the final light-emitting materials in Example 180, the rest of the preparation methods are the same as those in Example 180 for the organic EL device 86; DM-B, Ref.1 and Ref.2 are used to replace the sensitizer in the light-emitting layer of the above-mentioned device, and the other conditions are the same as those in Example 180 to prepare comparative examples 7 to 8, as shown in Table 6 for details.

[0293] Examples 183-206: Preparation of organic EL devices 89-112

[0294] Except for using mCBP or BH2 ​​as the main material, some compounds with TADF properties in the following Table 5 as sensitizers (doping ratio is 20%), and the luminescent compounds without TADF properties in Table 7 (doping ratio is 2wt%) to replace the materials in the light-emitting layer of Example 95, organic EL devices 89 to 112 are manufactured under the same conditions as organic EL device 1. Details are shown in Table 7.

[0295] Table 4

[0296]

[0297]

[0298] Table 5

[0299]

[0300] Table 6

[0301]

[0302] Table 7

[0303]

[0304] The structures of some compounds involved in the embodiments and comparative examples are as follows:

[0305]

[0306] At room temperature in the atmosphere, the luminescence characteristics of OLEDs devices 1-72 and comparative devices 1-3 prepared based on the materials with TADF characteristics in the embodiments of the present invention were measured, and the measurement results are summarized in Table 8. Among them, the current-brightness-voltage characteristics of the devices were completed by a Keithley source measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode, and the electroluminescence spectrum was measured by a PR655 spectrometer from Photo research. The external quantum efficiency of the device was calculated by the method of the literature Adv. Mater., 2003, 15, 1043-1048. EQE max is the maximum external quantum efficiency of the device, EQE 1000 For devices at 1000cd / m 2 External quantum efficiency at brightness. Device life is when the initial brightness is 1000cd / m 2 Under this condition, the device brightness decays to 900cd / m 2 The time elapsed.

[0307] Table 8

[0308]

[0309]

[0310] Figure 7 The spectra of compounds 1-1 and 2-36 in toluene at 77K are shown in Table 1. Figure 7 It can be seen that the energy level difference between the singlet and triplet states of the compounds in the present invention is very small and exhibits different excited state electron cloud configurations (enhancing the spin-orbit coupling between the singlet and triplet states), which is conducive to the rapid conversion of triplet excitons into singlet excitons, thereby improving the utilization rate of triplet excitons and reducing the concentration of triplet excitons, thereby reducing the efficiency roll-off in the device and improving the device stability.

[0311] As shown in Table 8, compared with DM-B (Comparative Example 1), the compound 1-1 (device 1) of the present invention has a greatly improved EQE compared with the single-donor spirocyclic compound DM-B by connecting another acceptor to the spirofluorene compound, which is specifically manifested as EQE max Increased from 26.8% to 36.2%, and the brightness is 1000cd / m 2 When the light emitting device is prepared based on the compound 1-1 of the present invention, the efficiency roll-off of the device is significantly smaller than that of the light emitting device based on DM-B.

[0312] The introduction of the Z group reduces the π-π stacking between molecules and also has a significant effect on improving the thermal stability and chemical stability of the luminescent molecules. By comparing device 1 with comparative example 2 and device 17 with comparative example 3, it can be seen that the introduction of the Z group significantly improves the external quantum efficiency of the device, significantly reduces the efficiency roll-off, and significantly extends the device life. Therefore, the performance of the device prepared based on the compound of the present invention is significantly better than that of Ref.1 and Ref.2 materials.

[0313] The peak values ​​and peak shapes of the devices prepared based on compounds 1-3, 1-4, 1-5, and 1-6 are basically consistent with those of Comparative Example 2, indicating that different linkers have little effect on the electroluminescent peak of the space charge transfer molecule. The peak value of the device prepared from compound 1-3 is slightly blue-shifted compared to the peak value of compound 1-1, because the presence of oxygen atoms interrupts the direct connection between the two benzene rings at the base, the degree of conjugation is weakened, and the peak value of the molecule will be slightly blue-shifted.

[0314] In addition, the present invention changes the luminescence characteristics of the material by adjusting the electron donating and electron withdrawing capabilities of the donor and acceptor groups to achieve luminescence from deep blue to green. For example, the luminescence peak of device 1 prepared by compound 1-1 is 487nm, and the light color is blue light; the luminescence peak of device 3 prepared by compound 2-1 is 508nm, and the light color is green light (see Figure 6 ).

[0315] The initial purpose of introducing the Z group was to increase the yield of the reaction and reduce production costs. Then, it was used as a steric group to increase the spatial distance between molecules, thereby reducing the aggregation-induced fluorescence quenching phenomenon. Surprisingly, the introduction of the Z group not only increases the spatial distance between molecules, but also changes the stacking mode of the molecules in the solid state. Take the single crystal structure of compound 2-45 as an example (see Figure 5 ), the results show that in the aggregated state, the intermolecular π-π stacking only exists in the benzene rings in the receptor group directly connected to the linker. The minimum overlap distance between these benzene rings is In addition, from Figure 5 From the side view in the figure, it can be seen that the π-π overlap of the benzene ring is also very small. According to the reported literature (Angew.Chem.Int.Ed.2022,61,e202206861), the receptor part of the spirocyclic molecule is prone to intermolecular π-π stacking due to its relatively flat structure, and this stacking mode is an important reason affecting the performance of the device. By comparing the stacking mode of the reported single crystals of similar molecules in the aggregated state, this small intermolecular π-π interaction of compound 2-45 originates from the introduction of the Z group.

[0316] The performance data of OLEDs devices prepared based on the materials of the present invention as the main materials are summarized in Table 9 below:

[0317] Table 9

[0318]

[0319] From the data shown in Table 9, it can be seen that the device performance of devices 73 to 81 is significantly better than that of comparative devices 4 to 6. This is because the spirocyclic main material involved in the present invention has suitable singlet, triplet and molecular orbital energy levels, and its unique non-planar spiro conjugation effect, vertical orthogonal conformation and steric hindrance effect can effectively improve the carrier transport balance in the device and broaden the exciton recombination area, thereby further improving the photoelectric performance and stability of the electroluminescent device.

[0320] The luminescent material in the present invention can be used as a sensitizing material in the luminescent layer to improve the luminescent efficiency of the device and reduce the efficiency roll-off of the device due to its excellent luminescent performance and low efficiency roll-off at high brightness. The specific device effects are shown in Table 10:

[0321] Table 10

[0322]

[0323] The advantages of thermally activated delayed fluorescent molecules as sensitizing materials for the light-emitting layer of the device are mainly manifested as follows: compared with traditional host materials, thermally activated delayed fluorescent materials can fully utilize triplet excitons through the antisystem crossing process, greatly improving the utilization rate of excitons. At the same time, the lifetime of triplet excitons is reduced, thereby reducing singlet-polaron annihilation and triplet-triplet annihilation, which is beneficial to improving the external quantum efficiency of the device and reducing the efficiency roll-off of the device, thereby extending the service life of the device. Since the doping concentration of the sensitizer is generally greater than 20%, in order to reduce the unfavorable energy transfer process, the π-π stacking between molecules should be reduced through molecular design. At the same time, the electroluminescence peak of the sensitizing material should overlap as much as possible with the ultraviolet-visible absorption peak of the guest material, which is beneficial to promote the fluorescence resonance energy transfer process (FRET), thereby improving the energy conversion efficiency between the sensitizing material and the guest material.

[0324] In short, the compounds of the present invention introduce Z groups on the linking groups, which changes the stacking mode of the molecules in the solid state, significantly reduces the π-π interaction between molecules, and can still maintain good luminescence performance at high doping concentrations. In addition, the compounds of the present invention have a high RISC rate and can reduce the lifetime of triplet excitons. The half-peak width of the luminescence peak of the compounds of the present invention in the device is greater than 60nm (see the electroluminescence spectra of some compounds Figure 6), the luminous range is mainly deep blue to green light, and can achieve large spectral overlap with the sensitized guest material, thereby improving energy utilization. At the same time, since the compound of the present invention is not directly connected to the donor and the acceptor, it is relatively easy to prepare deep blue or blue sensitizing materials, which can significantly improve the current problems of short life and large device efficiency roll-off of deep blue / blue OLED devices. From the data in Table 10 above, it can be seen that devices 82 to 88 prepared based on compounds 1-1, 2-36 and 2-45 as sensitizers show higher external quantum efficiency, lower efficiency roll-off and longer device service life compared to Comparative Examples 7 and 8. These results fully demonstrate that the compounds of the present invention are very excellent sensitizing materials.

[0325] The performance data of OLEDs prepared based on the TADF material of the present invention as a sensitizer and the luminescent material as the final emission material are summarized in Table 11 below:

[0326] Table 11

[0327]

[0328] Since the compounds with TADF properties in the present invention exhibit high luminous efficiency, OLEDs prepared based on the luminescent materials of the present invention have good stability. Therefore, the EQE of OLEDs devices prepared based on the materials with TADF properties in the present invention as sensitizers and the luminescent materials as the final emitters are generally high (generally greater than 30%), and can maintain a relatively high EQE under high brightness, indicating that the materials in the present invention can significantly improve the efficiency of the device and reduce the efficiency roll-off of the device.

[0329] In summary, the material synthesis and purification methods of the present invention are simple and easy, and have excellent luminescent properties, and can be used as functional materials in OLED devices, especially materials for the core luminescent layer. OLED devices prepared with the materials of the present invention can achieve higher external quantum efficiency, lower efficiency roll-off, and longer device service life.

[0330] In order to further demonstrate the effect of the introduction of the Z group on the thermal stability of the molecule and the EQE of the device in the present invention, we measured the thermal decomposition temperature of the compounds in the examples and DM-B, Ref.1 and Ref.2, as well as the PLQY in the solution. The specific data are shown in Table 12:

[0331] Table 12

[0332]

[0333]

[0334] From the data in Table 12, it can be seen that the PLQY of the compounds of the present invention in the solution is basically greater than 90%. From the comparison of the PLQY and thermal decomposition temperature of compounds 1-1, 1-98 with compounds Ref.1, Ref.2, it can be seen that the introduction of the Z group can further improve the thermal stability and chemical stability of the luminescent molecule, thereby ensuring the operational stability of the light-emitting device.

[0335] In summary, the material synthesis and purification methods of the present invention are simple and easy, and have excellent luminescent properties, and can be used as light-emitting layer materials of organic light-emitting devices, such as guest materials, sensitizing materials or host materials. OLEDs devices prepared based on the compounds of the present invention have the advantages of high external quantum efficiency, low efficiency roll-off and long life, and since most of the materials in the present invention are dark blue or blue thermally activated delayed fluorescent materials, they can effectively sensitize dark blue and blue luminescent materials, thereby improving the device efficiency and stability of dark blue / blue light materials.

[0336] The effects of the various devices described above indicate that the organic electroluminescent devices in the embodiments of the present invention have extremely high luminous efficiency and a small efficiency roll-off. The compounds of the present invention have the potential to replace precious metal phosphorescent materials and can be used to prepare organic electroluminescent devices with excellent performance.

[0337] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0338] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A compound having a structure represented by formula (I): in, X1, X2, and X3 each independently represent -P(R 15 )3-、-C(R 15 )(R 16 )-、-N(R 15 )-、-Bi(R 15 )-、-B(R 15 )-、-Si(R 15 )(R 16 )-、-Ge(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -C(=O)-, -P(R 15 )-、-P(=O)(R 15 )- or a single bond or does not exist; when at least one of X1, X2, and X3 does not exist, the carbon atom connected thereto is terminated with hydrogen; R1-R 14 And each R 15 , R 16 Each independently represents hydrogen, deuterium, a halogen atom, optionally replaced by one or more R 20 Substituted C1-C 15 Alkyl or optionally with one or more R 20 Substituted C6-C 20 Aryl; Z represents a halogen atom, optionally replaced by one or more R 20 Substituted C1-C 15 Alkyl, optionally with one or more R 20 Substituted C1-C 15 haloalkyl, optionally substituted with one or more R 20 Substituted C1-C 15 Alkoxy, optionally with one or more R 20 Substituted-N(R 17 )(R 18 ), optionally with one or more R 20 Substituted -Si(R 17 )(R 18 )(R 19 ), optionally with one or more R 20 Substituted -P(=O)(R 17 )(R 18 ), optionally with one or more R 20 Substituted C6-C 40 Aryl or optionally one or more R 20 substituted 5-40 membered heteroaryl; Every R 17 , R 18 , R 19 Each independently represents hydrogen, C1-C 15 Alkyl, C6-C 40 Aryl or 5-40 membered heteroaryl; L1 and L2 each independently represent a single bond, optionally replaced by one or more R 20 Substituted C6-C 40 Aryl or optionally one or more R 20 substituted 5-40 membered heteroaryl; A1 and A2 each independently represent optionally one or more R 20 Substituted with the following groups: C6-C 40 Aryl, 5-40 membered heteroaryl, -S(=O)2(R 21 )、-C(=O)(R 21 )、-N(R 21 )(R 22 )、-B(R 21 )(R 22 )、-P(=O)(R 21 )(R 22 ) or -Si(R 21 )(R 22 )(R 23 ); Every R 20 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, optionally with one or more R 24 Substituted C6-C 40 Aryl, optionally substituted with one or more R 24 substituted 5-40 membered heteroaryl, optionally substituted with one or more R 24 Substituted-N(R 21 )(R 22 ), optionally with one or more R 24 Substituted -Si(R 21 )(R 22 )(R 23 ) or optionally one or more R 24 Substituted-P(=O)(R 21 )(R 22 ); Every R 21 , R 22 , R 23 Each independently represents C6-C 40 Aryl or 5-40 membered heteroaryl; Every R 24 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, C6-C 40 Aryl or 5-40 membered heteroaryl.

2. The compound according to claim 1, characterized in that X1, X2, and X3 each independently represent -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -P(R 15 )- or a single bond or does not exist; when at least one of X1, X2, and X3 does not exist, the carbon atom connected thereto is terminated with hydrogen; Every R 15 , R 16 Each independently represents hydrogen, C1-C 15 Alkyl or C6-C 20 Aryl; preferably, each R 15 , R 16 Each independently represents a C1-C5 alkyl group or a C6-C 10 Aryl; More preferably, each R 15 , R 16 Each independently represents a methyl group or a phenyl group.

3. The compound according to claim 1 or 2, characterized in that It has the structure shown in formula (I-1): in, X3 means -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -P(R 15 )- or single bond; R 15 , R 16 Having the definition as set forth in claim 2; R1-R 14 , Z, L1, L2, A1, A2 have the definitions as described in claim 1.

4. The compound according to claim 1 or 2, characterized in that It has the structure shown in formula (I-2): in, X2 and X3 each independently represent -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -P(R 15 )- or single bond; R 15 , R 16 Having the definition as set forth in claim 2; R1-R 14 , Z, L1, L2, A1, A2 have the definitions as described in claim 1.

5. The compound according to claim 1 or 2, characterized in that It has the structure shown in formula (I-3): in, X1, X2, and X3 each independently represent -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -P(R 15 )- or single bond; R 15 , R 16 Having the definition as set forth in claim 2; R1-R 14 , Z, L1, L2, A1, A2 have the definitions as described in claim 1.

6. The compound according to any one of claims 1 to 5, characterized in that Z represents a halogen atom, C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, optionally with one or more R 20 Substituted-N(R 17 )(R 18 ), optionally with one or more R 20 Substituted -Si(R 17 )(R 18 )(R 19 ), optionally with one or more R 20 Substituted -P(=O)(R 17 )(R 18 ), optionally with one or more R 20 Substituted C6-C 20 Aryl or optionally one or more R 20 substituted 5-20 membered heteroaryl; Every R 17 , R 18 , R 19 Each independently represents C1-C 15 Alkyl, C6-C 20 Aryl or 5-20 membered heteroaryl; Every R 20 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, optionally with one or more R 24 Substituted C6-C 20 Aryl, optionally substituted with one or more R 24 substituted 5-20 membered heteroaryl, optionally substituted with one or more R 24 Substituted-N(R 21 )(R 22 ), optionally with one or more R 24 Substituted -Si(R 21 )(R 22 )(R 23 ) or optionally one or more R 24 Substituted -P(=O)(R 21 )(R 22 ); Every R 21 , R 22 , R 23 Each independently represents C6-C 20 Aryl or 5-20 membered heteroaryl; Every R 24 Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, C6-C 20 Aryl or 5-20 membered heteroaryl; Preferably, Z represents a halogen atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a trifluoromethyl group, a cyano group, a methoxy group, -N(CH3)2, -Si(CH3)3 or any one of the following groups: More preferably, Z represents F, methyl, ethyl, isopropyl, tert-butyl, methoxy, -N(CH3)2, -Si(CH3)3 or any one of the following groups: in, Dashed lines indicate binding bonds; Every R a -R r Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, C6-C 20 Aryl or 5-20 membered heteroaryl, preferably hydrogen, cyano, C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C6-C 20 Aryl or 5-20 membered heteroaryl, more preferably hydrogen, cyano, C1-C5 alkyl, C1-C5 haloalkyl, C6-C 10 The aryl group or the 5-20-membered heteroaryl group is more preferably hydrogen, cyano, trifluoromethyl, methyl, tert-butyl, phenyl or carbazolyl.

7. The compound according to any one of claims 1 to 6, characterized in that -L1-A1, -L2-A2 each independently represent the following groups: Preferably, -L1-A1 and -L2-A2 each independently represent the following groups: in, Dashed lines indicate binding bonds; Every R a -R v Each independently represents hydrogen, deuterium, a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C1-C 15 Alkoxy, C6-C 20 Aryl or 5-20 membered heteroaryl, preferably hydrogen, cyano, C1-C 15 Alkyl, C1-C 15 Halogenated alkyl, C6-C 20 Aryl or 5-20 membered heteroaryl, more preferably hydrogen, cyano, C1-C5 alkyl, C1-C5 haloalkyl, C6-C 10 The aryl group or the 5-20-membered heteroaryl group is more preferably hydrogen, cyano, trifluoromethyl, methyl, tert-butyl, phenyl or carbazolyl.

8. The compound according to any one of claims 1 to 7, characterized in that L1 and L2 each independently represent a single bond or a C6-C 20 Aryl, preferably single bond or C6-C 10 Aryl, more preferably a single bond or phenyl.

9. The compound according to any one of claims 1 to 8, characterized in that R1-R 14 Each independently represents hydrogen, C1-C 15 Alkyl or C6-C 20 Aryl; Preferably, R1-R6, R8-R9, R 11 -R 12 , R 14 Represents hydrogen, R7, R 10 , R 13 Each independently represents hydrogen, C1-C 15 Alkyl or C6-C 20 Aryl; More preferably, R7, R 10 , R 13 Each independently represents hydrogen, C1-C5 alkyl or C6-C 10 Aryl; Most preferably, R7, R 10 , R 13 Each independently represents hydrogen, methyl or phenyl.

10. The following compounds:

11. A method for preparing the compound according to any one of claims 1 to 10, comprising the following steps: Step S1: reacting a compound having a structure of formula (A) with a compound having a structure of formula (B) to generate a compound having a structure of formula (C); Step S2: reacting a compound having a structure of formula (C) to generate a compound having a structure of formula (D); Step S3: reacting a compound having a structure of formula (D) to generate a compound having a structure of formula (E); Step S4: reacting a compound having a structure of formula (E) with a compound having a structure of formula (F) to generate a compound having a structure of formula (I); in, M1, M2, M3 and M4 each independently represent F, Cl, Br or I; R 25 Represents C1-C 10 alkyl; Y represents hydrogen, deuterium, a halogen atom or -B(OR 26 )(OR 27 ); R 26 and R 27 Each independently represents hydrogen, deuterium or C1-C 10 Alkyl; or, R 26 and R 27 They are connected to each other and together with B and O atoms form a ring structure; X3 means -C(R 15 )(R 16 )-、-N(R 15 )-、-Si(R 15 )(R 16 )-, -O-, -S-, -Se-, -Te-, -S(=O)2-, -P(R 15 )- or single bond; R1~R 16 , Z, X1, X2, A1, A2, L1 and L2 have the definitions as described in any one of claims 1 to 9, or the compound having the structure of formula (I) is the compound described in claim 10.

12. An organic electroluminescent device, comprising, from bottom to top, a substrate, a first electrode, an organic functional material layer and a second electrode, wherein: The organic functional material layer comprises a light-emitting layer; the light-emitting layer comprises the compound according to any one of claims 1 to 10; Preferably, the organic functional material layer further comprises at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer; Preferably, the light-emitting layer comprises a host material and a dopant material, wherein the host material and / or the dopant material comprises the compound according to any one of claims 1 to 10; and / or Preferably, the organic electroluminescent device is a thermally activated sensitized fluorescent organic electroluminescent device.

13. A display device comprising the organic electroluminescent device according to claim 12.

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