Spiro structure-based organic boron fused ring compound and organic electroluminescent device thereof

Abstract

The invention provides an organoboron fused ring compound based on a spiro structure and an organic electroluminescent device thereof, the organoboron fused ring compound based on the spiro structure has a structure as shown in a formula (I), and each group in the compound as shown in the specification. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of organic photoelectric materials, and in particular relates to an organic boron condensed ring compound based on a spiro ring structure and an organic electroluminescent device thereof. Background Art

[0002] Organic electroluminescent devices have a series of advantages such as autonomous luminescence, fast response, high contrast, low energy consumption, wide field of view, and easy to achieve ultra-thin and light. Compared with liquid crystal displays, organic electroluminescent devices do not require backlight sources, use thinner organic material coatings and glass substrates, and can emit light when current passes through. Therefore, organic electroluminescent devices have broad application prospects. Organic electroluminescent devices are generally composed of an anode, a metal cathode, and an organic layer between them. Among them, the core of the organic layer is the organic electroluminescent material.

[0003] At present, a large number of organic electroluminescent materials with excellent performance have been developed one after another. Among them, the third-generation organic electroluminescent materials generally have a small singlet-triplet energy level difference (ΔE ST ), triplet excitons can be transformed into singlet excitons through reverse intersystem crossing (RISC) to emit light. Under electrical excitation, 100% exciton utilization can be achieved, and the internal quantum efficiency of the device can reach 100%. Therefore, it is regarded as one of the organic light-emitting materials with broad application prospects in the future.

[0004] In recent years, based on the condensed aromatic hydrocarbon skeleton, multi-resonance thermally activated delayed fluorescence (MR-TADF) materials have been synthesized by introducing electron-deficient centers (such as boron atoms) and electron-rich centers (such as nitrogen atoms) with opposite resonance effects. Due to the opposite resonance effects of nitrogen atoms and boron atoms, the electron clouds of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are significantly separated, thereby obtaining a smaller ΔE ST It also achieves narrowband emission, significantly improving color purity.

[0005] However, MR-TADF molecules with high planarity are prone to aggregation and face challenges related to aggregation-induced fluorescence quenching (ACQ) at high doping concentrations, resulting in problems such as low photoluminescence quantum yield (PLQY), spectral red shift and broadening, which seriously affect the efficiency and life of organic electroluminescent devices. Therefore, there is an urgent need to develop a new organic electroluminescent material to overcome the defects of the existing technology. Summary of the invention

[0006] In response to the above technical problems, the present invention provides an organic boron fused ring compound based on a spirocyclic structure and an organic electroluminescent device thereof, aiming to develop an organic electroluminescent material that can be used at a higher doping concentration. By incorporating a large steric hindrance group of spirofluorene into the MR-TADF skeleton, the intermolecular interaction is effectively inhibited, and the effect of anti-aggregation-induced fluorescence quenching is achieved. Secondly, the rigid structure of spirofluorene is conducive to reducing the relaxation of the excited state structure, thereby achieving a narrower half-peak width. Furthermore, the incorporation of the spirofluorene skeleton further reduces the ΔE ST , which is conducive to achieving an efficient reverse intersystem crossing process. In addition, spirofluorene and its derivatives have good thermal stability, solubility and electron and hole transport capabilities, so that the organic electroluminescent device prepared therefrom has a low driving voltage and high luminous efficiency. Therefore, the technical solution provided by the present invention is as follows.

[0007] As a first aspect of the present invention, there is provided an organic boron fused ring compound based on a spiro ring structure, wherein the organic boron fused ring compound has a structure as shown in formula (I):

[0008]

[0009] Wherein, R is selected from H, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino;

[0010] Z1-Z8 each independently represents CR1 or N, Z1-Z8 are the same or different, wherein in Z1-Z4, Z5-Z8, N is at most 3;

[0011] In Z1-Z8, each R1 is independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, cyano, nitro, hydroxyl, amino, trifluoromethyl, mercapto, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino;

[0012] Ar1 and Ar2 are the same or different and are independently selected from one or more C6-C 18 Aromatic ring or 5-18 membered heteroaromatic ring;

[0013] Y1 and Y2 each independently represent C(R2)2, C(R2)2C(R2)2, NR2, O, S, Se, SO2, a direct bond or do not exist;

[0014] X1 and X2 are each independently selected from N, O or S; when X1 is O or S, E1 and Y1 are absent; when X2 is O or S, E2 and Y2 are absent;

[0015] In the case where E1 and E2 exist, E1 and E2 are each independently selected from one or more C6-C 18 Aromatic ring or 5-18 membered heteroaromatic ring or C4-C 18 fat ring;

[0016] Each R2 is independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, cyano, N(=O)2, N(R3)2, OR3, SR3, C(=O)R3, P(=O)R3, Si(R3)3 or one or more R3-substituted C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C6-C 40 Any one of aryl and 5-40 membered heteroaryl, wherein R3 is selected from H, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino;

[0017] Any two adjacent substituents among E1 and Y1, E2 and Y2 can be connected to form a ring;

[0018] X3 is independently selected from a direct bond, N, O or S; in the case where X3 is a direct bond, O or S, Y3, Y4 and E3 are absent;

[0019] In the case where X3 is N, E3 is independently selected from C6-C 40 Aryl, 5-40 membered heteroaryl or not present, only one of Y3 and Y4 is present and Y3 or Y4 is independently selected from CO, C(R2)2, C(R2)2C(R2)2, O, S, Se, SO2, a direct bond or not present; or Y3 and Y4 are present at the same time, Y3 and Y4 are the same and are selected from CO or O;

[0020] Wherein the substituent is selected from C1-C 15 Any one of branched or straight chain alkyl groups, the heteroatom in the heteroaromatic ring is selected from any one of N, O, S, and Se, and the heteroatom in the heteroaryl group is selected from any one of N, O, S, and Se.

[0021] According to an embodiment of the present invention, the organic boron fused ring compound of the present invention has a general structure as shown in any one of formulas (I-1) to (I-4):

[0022]

[0023] Wherein, X2 in formula (I-2) and X1 in formula (I-3) are each independently selected from O or S, and X1 and X2 are the same or different; X1 and X2 in formula (I-4) are each independently selected from O or S, and X1 and X2 are the same or different;

[0024] Wherein, in formula (I-1) to formula (1-4), when X3 is selected from O or S, Y3 and E3 are absent;

[0025] In the case where X3 is N, E3 is independently selected from C6-C 40 Aryl, 5-40 membered heteroaryl or not present, only one of Y3 and Y4 is present and Y3 or Y4 is independently selected from CO, C(R2)2, C(R2)2C(R2)2, O, S, Se, SO2, a direct bond or not present; or Y3 and Y4 are present at the same time, Y3 and Y4 are the same and are selected from CO or O;

[0026] R, R2, Z1-Z8, Ar1, Ar2, Y1, Y2, Y3, E1, E2, and E3 have the same definitions as in the above embodiments.

[0027] According to an embodiment of the present invention, Ar1 and Ar2 are each independently selected from any one of the following groups:

[0028]

[0029] Furthermore, Ar1 and Ar2 are each independently selected from any one of the following groups:

[0030]

[0031] Furthermore, Ar1 and Ar2 are each independently selected from

[0032] According to an embodiment of the present invention, E1 and E2 are each independently selected from any one of the following groups:

[0033]

[0034] Furthermore, E1 and E2 are each independently selected from

[0035] According to an embodiment of the present invention, R2 is selected from hydrogen, methyl, tert-butyl, phenyl, The dotted lines represent the binding positions.

[0036] Furthermore, R2 is preferably hydrogen or tert-butyl.

[0037] According to an embodiment of the present invention, the heteroaryl group can be selected from Any one of .

[0038] According to an embodiment of the present invention, an organic boron fused ring compound based on a spiro ring structure provided by the present invention is selected from any one of the following specific structures:

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] As a second aspect of the present invention, an organic electroluminescent device is provided. The organic electroluminescent device comprises a light-emitting layer. The light-emitting layer comprises the above-mentioned organic boron condensed ring compound. The doping concentration of the organic boron condensed ring compound is 3wt%-20wt%.

[0046] According to an embodiment of the present invention, the organic electroluminescent device further comprises: a substrate, a first electrode, an organic functional material layer, and a second electrode in sequence; wherein the organic functional material layer comprises: a hole transport layer, a light emitting layer, and an electron transport layer. The hole transport layer is located on the first electrode, the light emitting layer is located on the hole transport layer, and the electron transport layer is located on the light emitting layer. The light emitting layer comprises a main material and a doping material, and the doping material is selected from any one of the organic boron condensed ring compounds based on a spiro ring structure in the above embodiments.

[0047] More specifically, the organic functional material layer is sequentially deposited with a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer in a direction from the first electrode to the second electrode.

[0048] Based on the above technical solution, the present invention provides an organic boron fused ring compound based on a spiro ring structure and an organic electroluminescent device thereof, which has at least one of the following beneficial effects:

[0049] (1) In the embodiments of the present invention, the resonance effect between the boron atom and the heteroatom is used to separate the HOMO and LUMO, thereby achieving a smaller ΔE ST and TADF effect, thereby achieving higher luminescence efficiency.

[0050] (2) In the embodiments of the present invention, the spirofluorene fragment is introduced to modify the rigid structure of the MR skeleton core to form a new skeleton, thereby enhancing the rigidity and conjugation degree of the entire molecule, further adjusting the photoelectric properties of the compound, and meeting the different performance requirements of organic light-emitting devices for materials. Specifically, the large steric hindrance group of spirofluorene can effectively inhibit the aggregation-induced fluorescence quenching problem caused by intermolecular interactions, thereby improving the device efficiency; secondly, the rigid structure of spirofluorene is conducive to reducing the excited state structural relaxation, thereby achieving a narrower half-peak width; furthermore, the incorporation of the spirofluorene skeleton further reduces ΔE ST , which is conducive to the realization of efficient reverse intersystem crossing process; finally, spirofluorene has good solubility, thermal stability and electron and hole transport capabilities, which can effectively regulate the carrier transport balance and improve device performance.

[0051] (3) In the embodiments of the present invention, different donor groups are introduced into the new MR skeleton formed after modifying the spirofluorene structure, which can change the light color of the organic boron condensed ring compound while maintaining a high luminous efficiency.

[0052] (4) In the embodiments of the present invention, the organic boron fused ring compound based on the spiro ring structure in the embodiments of the present invention is applied to the electroluminescent device, which can effectively improve the luminous efficiency and color purity of the electroluminescent device and achieve the effect of anti-aggregation-induced fluorescence quenching. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is the compound 1-1 of Example 1 of the present invention 1 H NMR spectrum;

[0054] Figure 2 It is a schematic structural diagram of an organic electroluminescent device of the present invention;

[0055] Figure 3 is a fluorescence spectrum (PL) diagram of compound 1-1 in an embodiment of the present invention in a thin film with different doping concentrations (using mCPCz as the main material);

[0056] Figure 4 It is the fluorescence spectrum (PL) diagram of BD3 in the thin film with different doping concentrations (using mCPCz as the main material) in the present invention;

[0057] Figure 5 is a fluorescence spectrum (PL) diagram of compounds 1-1, 2-1, 4-1, BD2, BD3 and BD4 in toluene solution in the examples of the present invention;

[0058] Figure 6 It is a transient photoluminescence decay spectrum diagram of compound 1-1 and BD3 in the examples of the present invention. DETAILED DESCRIPTION

[0059] The following is a detailed description of the compound represented by the above general formula I and the preparation method of the organic electroluminescent device containing the compound represented by the above general formula I and the organic electroluminescent device containing the compound represented by the above general formula I. However, the following examples are only used to illustrate the present invention, and the scope of the present invention is not limited thereto.

[0060] Example

[0061] Example 1: Synthesis of Compound 1-1

[0062] (Synthesis of Compound M1)

[0063] The synthetic route of compound M1 is as follows:

[0064]

[0065] Under nitrogen, add 1.54g (63.48mmol) magnesium strip, one grain of iodine and 40mL THF to a clean 100mL three-necked flask, slowly drop 12.71g (55.87mmol) 3,5-difluoro-4-chlorobromobenzene to the system, reflux for 2 hours after addition, then cool, add the newly prepared Grignard reagent to the reaction solution of 3g (25.39mmol) 2-aminobenzonitrile and 50mL THF at 0℃, move the system to room temperature and react for 24 hours after addition. After the reaction is completed, pour the reaction solution into about 200mL 1MHCl and reflux for 3 hours, then extract the reaction solution with ethyl acetate. After the organic phase is dried over anhydrous sodium sulfate, it is concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent is petroleum ether: ethyl acetate = 5:1 (V / V)) to obtain 4.08g of solid, with a yield of 60%. MS (EI): m / z 267.03 [M + ] Elemental analysis calculated value C 13 H8ClF2NO(%),: C, 58.34; H, 3.01; Cl, ​​13.24; F, 14.20; N, 5.23; O, 5.98, found value: C, 58.36; H, 2.99; Cl, ​​13.20; F, 14.24; N, 5.23; O, 5.98.

[0066] (Synthesis of Compound M2)

[0067] The synthetic route of compound M2 is as follows:

[0068]

[0069] Add 1g M1 (3.74mmol) and 50mL 80% sulfuric acid to a clean 100mL two-necked bottle, stir at 60℃ for 30 minutes, then cool to 5℃, add sodium nitrite solution (0.31g, 4.48mmol) dropwise, react at this temperature for 2 hours, move the reaction solution to 70℃ and stir overnight after the reaction is completed, stop heating after the reaction is completed, and let the reaction system cool to room temperature by itself. Pour the reaction solution into about 100mL water and filter. The solid is recrystallized from ethanol and toluene to obtain 0.77g of yellow solid, with a yield of 80%. MS (EI): m / z 250.00 [M + ] Elemental analysis calculated value C 13 H5ClF2O(%),: C, 62.30; H, 2.01; Cl, ​​14.14; F, 15.16; O, 6.38, found value: C, 62.28; H, 2.03; Cl, ​​14.15; F, 15.16; O, 6.37.

[0070] (Synthesis of Compound L1)

[0071] The synthetic route of compound L1 is as follows:

[0072]

[0073] Under nitrogen, 1.55g (4.79mmol) 2-bromotriphenylamine and 15mL THF solvent were added to a clean 50mL two-necked bottle. After dissolution, 1.99mL (4.79mmol) n-butyl lithium (2.4M n-hexane solution) was added dropwise at -78°C. After the addition was completed, the temperature was controlled to react for 1 hour. Then 1g M2 (3.99mmol, dissolved in 15mL THF) was added. After the addition was completed, the reaction was moved to room temperature. After 2 hours, 12% hydrochloric acid aqueous solution was added dropwise to the system to adjust the pH to 2. The reaction was refluxed for 4 hours. After the reaction was completed, the reaction solution was poured into about 50mL 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, and then 1.2g of solid was obtained, with a yield of 69%. MS (EI): m / z 477.11 [M+]. Elemental analysis calculated value C 31 H 18 ClF2N(%),: C, 77.91; H, 3.80; Cl, ​​7.42; F, 7.95; N, 2.93, found: C, 77.90; H, 3.80; Cl, ​​7.43; F, 7.93; N, 2.95.

[0074] (Synthesis of Compound R1)

[0075] The synthetic route of compound R1 is as follows:

[0076]

[0077] Under nitrogen conditions, 1g (2.09mmol) L1, 1.29g (4.60mmol) 3,6-di-tert-butylcarbazole, 2.73g (8.37mmol) cesium carbonate, and 20mL solvent DMF were added to a clean 50mL three-necked flask in sequence, and the system was heated to 150°C for 12 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 200mL of water and filtered. The solid was recrystallized from ethanol and toluene to obtain 1.8g of white solid with a yield of 92%. MS (EI): m / z 995.49 [M + ] Elemental analysis calculated value C 71 H 66 ClN3(%),: C, 85.55; H, 6.67; Cl, ​​3.56; N, 4.22, found: C, 85.54; H, 6.67; Cl, ​​3.56; N, 4.23.

[0078] (Synthesis of Compound 1-1)

[0079] The synthetic route of compound 1-1 is as follows:

[0080]

[0081] Under nitrogen, add 1g (1.00mmol) R1 and 30mL anhydrous tert-butylbenzene to a clean 50mL three-necked flask, stir and dissolve, then add 1.70mL (1.3M, 2.21mmol) tert-butyl lithium at -40℃, react for 1 hour, then add 0.63g (2.51mmol) BBr3 at -40℃, react for 2 hours, then add 0.52g (4.01mmol) diisopropylethylamine in an ice-water bath, heat the system to 160℃ half an hour later and react overnight. After the reaction is complete, pour the reaction solution into about 100mL saturated sodium acetate aqueous solution and extract it with dichloromethane. After the organic phase is dried over anhydrous sodium sulfate, it is concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent is petroleum ether: dichloromethane = 5:1 (volume ratio)) to obtain 0.18g, with a yield of 22%. MS (EI): m / z 969.52 [M + ] Elemental analysis calculated value C 71 H 64 BN3(%),: C, 87.90; H, 6.65; B, 111; N, 4.33, found: C, 87.87; H, 6.65; B, 1.14; N, 4.33.

[0082] Example 2: Synthesis of Compound 1-23

[0083] (Synthesis of Compound M3)

[0084] The synthetic route of compound M3 is as follows:

[0085]

[0086] Under nitrogen conditions, 1g (2.09mmol) L1, 0.64g (2.3mmol) 3,6-di-tert-butylcarbazole, 1.36g (4.18mmol) cesium carbonate, and 30mL solvent DMF were added to a clean 50mL three-necked flask in sequence, and the system was heated to 120℃ 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 100mL of water and filtered. The solid was further purified by column chromatography (350 mesh silica gel, eluent was petroleum ether: dichloromethane = 8:1 (volume ratio)) to obtain 1.41g of white solid, with a yield of 85%. MS (EI): m / z 736.30 [M + ] Elemental analysis calculated value C 51 H 42 ClFN2(%),: C, 83.07; H, 5.74; Cl, ​​4.81; F, 2.58; N, 3.80, found: C, 83.07; H, 5.74; Cl, ​​4.81; F, 2.58; N, 3.80.

[0087] (Synthesis of Compound R15)

[0088] The synthetic route of compound M3 is as follows:

[0089]

[0090] Under nitrogen conditions, 1g (1.36mmol) M3, 0.42g (1.49mmol) phenoxazine, 0.88g (2.71mmol) cesium carbonate, and 30mL solvent DMF were added to a clean 50mL three-necked flask in sequence, and the system was heated to 120℃ 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 100mL of water and filtered. The solid was further purified by column chromatography (350 mesh silica gel, eluent was petroleum ether: dichloromethane = 8:1 (volume ratio)) to obtain 1.00g of white solid, with a yield of 85%. MS (EI): m / z 899.36 [M + ] Elemental analysis calculated value C 63 H 50 ClN3O(%),: C, 84.02; H, 5.60; Cl, ​​3.94; N, 4.67; O, 1.78, found value: C, 84.02; H, 5.60; Cl, ​​3.94; N, 4.70; O, 1.75.

[0091] (Synthesis of Compound 1-23)

[0092] The synthetic route of compound 1-23 is as follows:

[0093]

[0094] Under nitrogen, add 2g (2.59mmol) R15 and 50mL anhydrous xylene to a clean 100mL three-necked flask, stir and dissolve, then add 2.39mL (1.3M, 3.11mmol) tert-butyl lithium at -40℃, react for 1 hour, then add 1.3g (5.19mmol) BBr3 at -40℃, react for 2 hours, then add 0.84g (6.48mmol) diisopropylethylamine in an ice-water bath, heat the system to 135℃ half an hour later and react overnight. After the reaction is complete, pour the reaction solution into about 100mL saturated sodium acetate aqueous solution and extract it with dichloromethane. After the organic phase is dried over anhydrous sodium sulfate, it is concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent is petroleum ether: dichloromethane = 5:1 (volume ratio)) to obtain 0.35g, with a yield of 18%. MS(EI):m / z 873.39[M + ] Elemental analysis calculated value C 63 H 48 BN3O(%),: C, 86.59; H, 5.54; B, 1.24; N, 4.81; O, 1.83, found value: C, 86.59; H, 5.54; B, 1.25; N, 4.80; O, 1.83.

[0095] The synthesis method of intermediates L2-L5 is similar to that of L1, the synthesis method of M4-M7 is similar to that of M3, the synthesis method of R2-R14, R27-R42 is similar to that of R1, and the synthesis method of R16-R26, R43-R54 is similar to that of R15, as shown in Table 1 below; the synthesis method of Examples 3-54 is similar to that of the final product in Example 1, as shown in Table 2 below.

[0096] Figure 1 is the compound 1-1 in Example 1 of the present invention 1 H NMR spectrum.

[0097] Table 1

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] Table 2

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112] Synthesis of Comparative Example BD4

[0113] (Synthesis of Compound M8)

[0114] The synthetic route of compound M8 is as follows:

[0115]

[0116] Under nitrogen conditions, add 2.03g (7.89mmol) of iodine, 1.32g (19.95mmol) and 20mL of solvent acetic acid to a clean 50mL three-necked flask, heat to 100℃, break the vacuum, add 1g (3.99mmol) of M2, and then heat to 120℃ for 5 hours. After the reaction is completed, pour the reaction solution into about 50mL of water, and then extract the reaction solution with dichloromethane. After the organic phase is dried over anhydrous sodium sulfate, it is concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent is petroleum ether: ethyl acetate = 5:1 (V / V)) to obtain 0.85g of solid, with a yield of 90%. MS (EI): m / z 236.02 [M + ] Elemental analysis calculated value C 13 H7ClF2(%),: C, 65.98; H, 2.98; Cl, ​​14.98; F, 16.06, found value: C, 65.98; H, 2.99; Cl, ​​14.98; F, 16.05.

[0117] (Synthesis of Compound M9)

[0118] The synthetic route of compound M9 is as follows:

[0119]

[0120] Under nitrogen, add 1g (4.23mmol) M8, 1.19g (10.56mmol) and 20mL THF solvent to a clean 50mL three-necked flask, add 2.40g (16.90mmol) iodomethane at 0℃, and then move to room temperature to react for 5 hours. After the reaction is completed, pour the reaction solution into about 50mL water and extract it with dichloromethane. After the organic phase is dried over anhydrous sodium sulfate, it is concentrated under reduced pressure and further purified by column chromatography (350 mesh silica gel, eluent is petroleum ether) to obtain 0.9g of solid, with a yield of 80%. MS (EI): m / z 264.05 [M + ] Elemental analysis calculated value C 15 H 11 ClF2(%),: C, 68.06; H, 4.19; Cl, ​​13.39; F, 14.35, found: C, 68.07; H, 4.18; Cl, ​​13.40; F 14.34.

[0121] (Synthesis of Compound M10)

[0122] The synthetic route of compound M10 is as follows:

[0123]

[0124] M10 was prepared by a method similar to that of compound R1 in Example 1, except that 1 g (3.78 mmol) of M9 was used for the reaction to obtain 2.67 g of solid with a yield of 90%. MS (EI): m / z 782.44 [M + ] Elemental analysis calculated value C 55 H 59 ClN2(%),: C, 84.31; H, 7.59; Cl, ​​4.52; N, 3.58, found: C, 84.33; H, 7.59; Cl, ​​4.52; N, 3.56.

[0125] (Synthesis of Compound BD4)

[0126] The synthetic route of compound BD4 is as follows:

[0127]

[0128] Compound BD4 was prepared by a method similar to that of compound 1-1 in Example 1, except that 1 g (1.28 mmol) of M10 was used for the reaction, and 0.19 g of compound BD4 was obtained after purification, with a yield of 20%. MS (EI): m / z 756.46 [M+]. Elemental analysis calculated values ​​C55H57BN2 (%): C, 87.28; H, 7.59; B, 1.43; N, 3.70, measured values: C, 87.25; H, 7.60; B, 1.46; N, 3.71.

[0129] Example 55: Preparation of organic electroluminescent device 1 (abbreviated as organic EL device 1).

[0130] 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 formed on a transparent anode 2 preformed on a glass substrate 1 to prepare a Figure 2 The organic electroluminescent device shown.

[0131] Specifically, a glass substrate 1 with an ITO film having a thickness of 100 nm was ultrasonically treated in a Decon 90 alkaline cleaning solution, rinsed in deionized water, cleaned three times in acetone and ethanol respectively, baked in a clean environment until moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The glass substrate 1 with an ITO electrode was placed in a vacuum chamber and evacuated to 4×10 -4 -2×10 -5Pa. Then, on the glass substrate 1 with the ITO electrode 2, 5% HIL1 / 95% HTL1 was evaporated at a evaporation rate of 0.2nm / s to form a layer with a thickness of 10nm as the hole injection layer 3. On the hole injection layer 3, HTL1 was evaporated at a evaporation rate of 2.0nm / s to form a layer with a thickness of 30nm as the hole transport layer 4. On the hole transport layer 4, BH1 was evaporated at a evaporation rate of 0.2nm / s to form a layer with a thickness of 20nm as the electron blocking layer 5. On the electron blocking layer 5, dual-source co-evaporation was performed at a evaporation rate of 2.0nm / s for BH1 as the main material and a evaporation rate of 0.16nm / s for compound 1-1 as the doping material to form a layer with a thickness of 20nm as the light-emitting layer 6, and the doping weight ratio of compound 1-1 was 10wt%. On the light-emitting layer 6, SF3-TRZ was evaporated at a evaporation rate of 2.0 nm / s to form a layer with a thickness of 10 nm as a hole blocking layer 7. On the hole blocking layer 7, 50% ETL1 / 50% Liq was evaporated at a evaporation rate of 2.0 nm / s to form a layer with a thickness of 40 nm as an electron transport layer 8. On the electron transport layer 8, 8-hydroxyquinoline-lithium (Liq) was evaporated at a evaporation rate of 0.2 nm / s to form a layer with a thickness of 2 nm as an electron injection layer 9. Finally, aluminum was evaporated at a evaporation rate of more than 3.0 nm / s to form a cathode 10 with a thickness of 100 nm.

[0132] Examples 56 to 108: Preparation of organic EL devices 2 to 54.

[0133] Organic EL devices 2 to 54 were prepared under the same conditions as those of the organic EL device 1, except that the compounds shown in the following Table 3 were used instead of the compounds in the layers of Example 55, respectively.

[0134] Examples 109-147: Preparation of organic EL devices 55-93.

[0135] Organic EL devices 55 to 93 were prepared under the same conditions as those of the organic EL device 1 except that the light-emitting layer compounds shown in the following Table 5 were used instead of the light-emitting layer compounds of Example 55.

[0136] Examples 148-160: Preparation of organic EL devices 94-106.

[0137] Organic EL devices 94 to 106 were prepared under the same conditions as those of the organic EL device 1 except that the light-emitting layer compounds shown in the following Table 6 were used instead of the light-emitting layer compounds of Example 55.

[0138] Comparative Examples 1 to 3: Preparation of Organic EL Devices Comparative Examples 1 to 3.

[0139] Organic EL device Comparative Examples 1 to 3 were prepared under the same conditions as those of the organic EL device 1, except that the compounds shown in the following Table 3 were used instead of the compounds in the layers of Example 55, respectively.

[0140] Figure 2 This is a schematic diagram of the structure of the organic electroluminescent device of Examples 55-160 of the present invention and Comparative Examples 1-3, wherein 1 is a substrate, 2 is an anode (i.e., a first electrode), 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode (i.e., a second electrode).

[0141] Table 3

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149] The structures of the compounds involved in the embodiments are as follows:

[0150]

[0151] When a DC voltage was applied in the atmosphere at room temperature, the organic EL devices prepared in Examples 55 to 160 were measured. The luminescence characteristics of the organic EL devices 1 to 106 and the organic EL devices prepared in Comparative Examples 1 to 3 are shown in Table 4. The luminescence characteristics of the organic EL devices prepared with different doping ratios of the luminescent materials are shown in Table 5. The luminescence characteristics of the organic EL devices before and after sensitization are shown in Table 6.

[0152] The current-brightness-voltage characteristics of the device were measured 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 using the method of Adv. Mater., 2003, 15, 1043-1048.

[0153] Table 4

[0154]

[0155]

[0156] Table 5

[0157]

[0158]

[0159] Table 6

[0160]

[0161]

[0162]

[0163] Figure 3 is a fluorescence spectrum (PL) diagram of compound 1-1 in an embodiment of the present invention in a thin film with different doping concentrations (using mCPCz as the main material); Figure 4 It is the fluorescence spectrum (PL) diagram of BD3 in the thin film with different doping concentrations (using mCPCz as the main material) in the present invention; Figure 5 It is a fluorescence spectrum (PL) diagram of compounds 1-1, 2-1, 4-1, BD2, BD3 and BD4 in toluene solution in the examples of the present invention.

[0164] From Table 5, Figure 3-Figure 5 It can be seen that, whether in the doped film or the prepared organic EL device, the spirocyclic organic boron condensed ring compound of the present invention does not produce obvious red shift and broadening of the luminescence peak as the doping ratio increases; and in the organic EL device, as the doping ratio increases, its external quantum efficiency is also maintained within a certain range, and no obvious decrease is found. In contrast, BD2 and BD3, as the doping ratio increases, the luminescence peak undergoes obvious red shift and broadening, and the efficiency decreases significantly. In addition, due to the introduction of the spirofluorene structure, the HOMO energy level and carrier transport capacity of the molecule are adjusted, and ultimately the turn-on voltage of the device is significantly reduced in the device, and the performance of the device is improved.

[0165] Further, by Figure 5 As can be seen from Table 4, the optical properties of the molecule can be further adjusted by modifying the donor part of the MR skeleton, thereby meeting the different performance requirements of the organic light-emitting device for the material.

[0166] Figure 6 It is a transient photoluminescence decay spectrum diagram of compound 1-1 and BD3 in the examples of the present invention.

[0167] Depend on Figure 6 It can be seen that compared with the comparative molecule BD3, the delayed component of compound 1-1 incorporating the spirofluorene skeleton is significantly increased, and the TADF property is more obvious, that is, the utilization of triplet excitons is more sufficient.

[0168] As can be seen from Table 6, the life of the devices made by adding sensitizers such as 5Cz-TRZ, 3Cz-TRZ and 5Cz-BO is greatly increased compared with the unsensitized devices, and the stability is improved; and the stability of the device using the organic boron condensed ring compound based on the spiro structure of the present invention as the light-emitting layer material is higher than the stability of the comparative example device.

[0169] In summary, this type of material has excellent photoelectric properties and can be used as the light-emitting material of the organic emission layer of an organic electroluminescent device. It can simplify the production process of the organic electroluminescent device, reduce the loss of host-guest energy transfer, balance carrier transport, and ultimately realize an organic light-emitting diode device with both high external quantum efficiency and narrow-band emission.

[0170] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An organic boron fused ring compound based on a spiro ring structure, characterized in that: The organic boron fused ring compound has a structure as shown in formula (I): Wherein, R is selected from H, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino; Z1-Z8 each independently represents CR1 or N, Z1-Z8 are the same or different, wherein in Z1-Z4, Z5-Z8, N is at most 3; In Z1-Z8, each R1 is independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, cyano, nitro, hydroxyl, amino, trifluoromethyl, mercapto, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino; Ar1 and Ar2 are the same or different and are independently selected from one or more C6-C 18 Aromatic ring or 5-18 membered heteroaromatic ring; Y1 and Y2 each independently represent C(R2)2, C(R2)2C(R2)2, NR2, O, S, Se, S O2, a direct bond or do not exist; X1 and X2 are each independently selected from N, O or S; when X1 is O or S, E1 and Y1 are absent; when X2 is O or S, E2 and Y2 are absent; In the case where E1 and E2 exist, E1 and E2 are each independently selected from one or more C6-C 18 Aromatic ring or 5-18 membered heteroaromatic ring or C4-C 18 fat ring; Each R2 is independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, cyano, N(=O)2, N(R3)2, OR3, SR3, C(=O)R3, P(=O)R3, Si(R3)3 or one or more R3-substituted C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C6-C 40 Any one of aryl and 5-40 membered heteroaryl, wherein R3 is selected from H, substituted or unsubstituted C1-C 15 Alkyl, alkoxy, silyl, and substituted or unsubstituted C6-C 18 Any one of aryl, arylamino, heteroaryl, and heteroarylamino; Any two adjacent substituents among E1 and Y1, E2 and Y2 can be connected to form a ring; X3 is independently selected from a direct bond, N, O or S; in the case where X3 is a direct bond, O or S, Y3, Y4 and E3 are absent; In the case where X3 is N, E3 is independently selected from C6-C 40 Aryl, 5-40 membered heteroaryl or not present, only one of Y3 and Y4 is present and Y3 or Y4 is independently selected from CO, C(R2)2, C(R2)2C(R2)2, O, S, Se, SO2, a direct bond or not present; or Y3 and Y4 are present at the same time, Y3 and Y4 are the same and are selected from CO or O; Wherein the substituent is selected from C1-C 15 Any one of branched or straight chain alkyl groups, the heteroatom in the heteroaromatic ring is selected from any one of N, O, S, and Se, and the heteroatom in the heteroaryl group is selected from any one of N, O, S, and Se.

2. The organic boron fused ring compound according to claim 1, characterized in that: The organic boron fused ring compound has a general structure as shown in any one of formulas (I-1) to (I-4): Wherein, X2 in formula (I-2) and X1 in formula (I-3) are each independently selected from O or S, and X1 and X2 are the same or different; X1 and X2 in formula (I-4) are each independently selected from O or S, and X1 and X2 are the same or different; Wherein, in formula (I-1) to formula (1-4), when X3 is selected from O or S, Y3 and E3 are absent; In the case where X3 is N, E3 is independently selected from C6-C 40 Aryl, 5-40 membered heteroaryl or not present, only one of Y3 and Y4 is present and Y3 or Y4 is independently selected from CO, C(R2)2, C(R2)2C(R2)2, O, S, Se, SO2, a direct bond or not present; or Y3 and Y4 are present at the same time, Y3 and Y4 are the same and are selected from CO or O; R, R2, Z1-Z8, Ar1, Ar2, Y1, Y2, Y3, Y4, E1, E2, and E3 are as defined in claim 1.

3. The organic boron fused ring compound according to any one of claims 1 to 2, characterized in that: Ar1 and Ar2 are each independently selected from any one of the following groups:

4. The organic boron fused ring compound according to claim 1, characterized in that: E1 and E2 are each independently selected from any one of the following groups:

5. The organic boron fused ring compound according to claim 1, characterized in that: The heteroaryl group is selected from Any one of .

6. The organic boron fused ring compound according to claim 1, characterized in that: R2 is selected from hydrogen, methyl, tert-butyl, phenyl, Any one of the above, wherein the dotted line represents the binding bond position.

7. The organic boron fused ring compound according to claim 1, characterized in that: The organic boron fused ring compound is selected from any one of the following compounds:

8. An organic electroluminescent device, characterized in that: The light-emitting layer of the organic electroluminescent device comprises the organic boron condensed-ring compound according to any one of claims 1 to 7, and the doping concentration of the organic boron condensed-ring compound is 3 wt % to 20 wt %.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic electroluminescent device comprises in sequence: a substrate, a first electrode, an organic functional material layer and a second electrode; The organic functional material layer includes, in sequence from the first electrode to the second electrode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer.

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