Multi-resonance thermal activation delayed fluorescence high-molecular compound based on polynorbornene main chain and space heavy atom effect, preparation method and organic electroluminescent device

Abstract

The invention discloses a multi-resonance thermal activation delayed fluorescence high-molecular compound based on a polynorbornene main chain and a space heavy atom effect, a preparation method and an organic electroluminescent device, and belongs to the field of organic luminescent materials. The high-molecular compound comprises a heavy atom-containing structural unit, a multiple resonance thermal activation delayed fluorescence unit and a non-conjugated norbornene side chain, so that the anti-intersystem crossing process of an MR-TADF unit can be improved, the spectrum width and peak position of a luminescent spectrum are not influenced, and a new support is provided for developing a high-performance MR-TADF organic light-emitting device.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to an organic electroluminescent material, specifically a multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect. Background Art

[0002] Organic light-emitting diodes (OLEDs) have the advantages of bright colors, fast response speed, large viewing angle, low driving voltage, energy saving, light weight and flexible display. The fluorescent materials of traditional OLEDs are expensive, highly toxic, and have low exciton utilization. The emergence of thermally activated delayed fluorescence (TADF) materials has promoted the development of OLED technology.

[0003] The frontier molecular orbitals in thermally activated delayed fluorescence (TADF) materials have a small overlap, where the frontier molecular orbitals refer to the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), i.e., the HOMO-LUMO energy level orbital, with a small singlet-triplet energy level difference (ΔE ST <0.3eV), can convert triplet excitons (T1) into singlet states (S1) through the reverse intersystem crossing process (RISC), produce delayed fluorescence, and achieve 100% exciton utilization, which is an important material system for the development of high-efficiency OLED devices.

[0004] Multiresonance Thermally Activated Delayed Fluorescence (MR-TADF) materials are based on an intramolecular push-pull electron system formed by electron-rich and electron-deficient atoms embedded in a fused aromatic ring skeleton in a molecular framework. They have the characteristics of thermally activated delayed fluorescence effect and narrow spectrum emission, with an exciton utilization rate of up to 100% and high luminescent color purity. They have broad application prospects in the preparation of high-efficiency, wide-color gamut organic light-emitting devices. However, unlike traditional TADF materials with donor-acceptor structures, MR-TADF uses the resonance effect of electron-rich atoms and electron-deficient atoms in the fused molecular framework to regulate the distribution of frontier molecular orbitals, making it difficult to achieve effective HOMO and LNMO separation. Therefore, MR-TADF usually exhibits a large singlet energy level difference (ΔE ST), low Reverse Intersystem Crossing (RISC) rate (k RISC ≈10 4 -10 5 s -1 ) and a longer fluorescence lifetime, which in turn leads to a serious device efficiency roll-off.

[0005] Recent studies have shown that embedding heavy atoms in the MR-TADF skeleton or introducing structural units containing heavy atoms on its periphery to enhance spin-orbit coupling (SOC) using its heavy atom effect is an effective means to promote the RISC process of MR-TADF units. However, the above means will inevitably lead to changes in molecular configuration and excited state characteristics, bringing about problems of luminescence spectrum broadening and spectrum shift. How to improve the RISC process of MR-TADF without affecting the luminescence peak position and spectrum width is a question that needs to be answered at present. At present, research on MR-TADF materials is mostly concentrated in the field of small molecules, such as the multi-resonance thermally activated delayed fluorescence material with a spatial stereoscopic structure disclosed in CN 113651841B. There are few reports on efficient MR-TADF polymer compounds. Compared with small molecule MR-TADF materials, polymer materials are more suitable for solution processing technology to prepare large-area, low-cost light-emitting devices. Summary of the invention

[0006] In order to solve the shortcomings of the prior art, the present invention proposes a multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, a preparation method and an organic electroluminescent device. The polymer compound contains a heavy atom structural unit (Heavy Atom Unit, HAU) and a MR-TADF unit followed by a non-conjugated norbornene side chain. The molecular orbitals between the two can produce spatial interactions, which can effectively reduce the delayed fluorescence lifetime and improve the device performance.

[0007] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0008] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the molecular formula of which is shown in formula (I):

[0009]

[0010] Wherein, 0<x≤1, n is an integer from 2 to 9999;

[0011] is a structural unit containing a heavy atom, wherein the atomic number of the heavy atom is greater than 13,

[0012] is a multiple resonance thermally activated delayed fluorescence unit,

[0013] is a main unit, selected from any one of the following groups formed by lacking a hydrogen atom in formulas H-1 to H19:

[0014]

[0015]

[0016] Among them, the dotted line indicates bonding or non-bonding.

[0017] K is selected from B, N, R 3 -P=one of O,

[0018] Q 1 , Q 2 and Q 3 Each independently selected from R 4 -CR 5 , R 6 -Si-R 7 , R 8 -Ge-R 9 , R 10 -B, R 11 -P=O、R 3 - one of P, O, S, Se, Te, C=O, O=S=O,

[0019] R 1 ~R 11 Each independently selected from H, halogen, -CN, -NO 2 , substituted or unsubstituted C1-C22 straight-chain alkyl, substituted or unsubstituted C1-C22 branched alkyl, substituted or unsubstituted C1-C22 cycloalkyl, substituted or unsubstituted C1-C22 alkoxy chain, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a fusion of the above groups; or R 1 ~R 11 They can be connected by chemical bonds to form a bridge structure.

[0020] Preferably, the main unit is selected from any one of the groups formed by lacking a hydrogen atom in the following formulas H-1-1 to H-19-1:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] In the present invention, the unit containing a heavy atom is selected from any one of the following formulas HAU-1 to HAU-8:

[0028]

[0029]

[0030] Among them, the dotted line indicates bonding or non-bonding;

[0031] K is selected from B, N, R 3 -P=one of O;

[0032] Q 4 , Q 5 and Q 6 Each independently selected from R 4 -Si-R 5 , R 6 -Ge-R 7 , S, Se, Te;

[0033] R in formula HAU-1 to HAU-8 1 ~R 7 Each is independently selected from H, halogen, -CN, -NO 2 , substituted or unsubstituted C1-C22 straight-chain alkyl, substituted or unsubstituted C1-C22 branched alkyl, substituted or unsubstituted C1-C22 cycloalkyl, substituted or unsubstituted C1-C22 alkoxy chain, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a fusion of the above groups; or R 1 ~R 7 They can be connected by chemical bonds to form a bridge structure.

[0034] Preferably, the above-mentioned unit containing a heavy atom is selected from any one of the groups formed by lacking a hydrogen atom in the following formulas HAU-1-1 to HAU-8-1:

[0035]

[0036]

[0037]

[0038] In the present invention, the multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1 to MR-4:

[0039]

[0040] Wherein, G1 to G2 are each independently selected from non-bonded, single-bonded, BR 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 , R 1 -P=O, C=O, S=O, O=S=O, O, S, Se or Te;

[0041] M1~M4 are selected from BR 1 NR 1 , PR 1 , R 1 -P=O, C=O, S=O, O=S=O, O, S, Se or Te;

[0042] K1-K2 are each independently selected from B, N, P, P=O;

[0043] BR in G1~G2 and M1~M4 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 are each independently selected from substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl; or said BR 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 Through a linker or single bond to the adjacent A 1 ~A 5 One or two bonds in the 1 , R 1 -CR2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 A is connected to one or two adjacent M1 to M4 via a linker or a single bond; 1 ~A 5 Each is independently selected from a C6-C60 aromatic ring or a C3-C60 aromatic heterocyclic ring.

[0044] Among them, A in the above-mentioned multiple resonance thermally activated delayed fluorescence unit 1 ~A 5 Each is independently selected from any one of the following formulas 1 to 53:

[0045]

[0046]

[0047] Wherein, L1, L2 and L3 are each independently selected from: (i) H, halogen, -CN, -NO 2 , OH; (ii) a straight chain, branched or cycloalkyl or alkoxy chain containing 1 to 30 carbon atoms, wherein one or more non-adjacent carbon atoms may be substituted by O, S, Si, -CO-O-, and one or more hydrogen atoms may be substituted by halogen; (iii) a substituted or unsubstituted C6-C60 aryl or C5-C60 heteroaryl; L1, L2 and L3 may be connected by chemical bonds to form a bridge structure.

[0048] Preferably, the above-mentioned multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1-1 to MR-4-6:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] Among them, R 1 ~R 12 Each is independently selected from H, halogen, -CN, -NO 2, substituted or unsubstituted C1-C22 straight-chain alkyl, substituted or unsubstituted C1-C22 branched alkyl, substituted or unsubstituted C1-C22 cycloalkyl, substituted or unsubstituted C1-C22 alkoxy chain, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a fusion of the above groups; or R 1 ~R 12 They are connected by chemical bonds to form a bridge structure.

[0055] Furthermore, the above-mentioned multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1-1-1 to MR-4-5-1:

[0056]

[0057]

[0058]

[0059] Furthermore, the multi-resonance thermally activated delayed fluorescence polymer compound based on the polynorbornene main chain and the spatial heavy atom effect is one of the following formulas P1-P82:

[0060]

[0061]

[0062]

[0063]

[0064] In the present invention, the method for preparing the above-mentioned multi-resonance thermally activated delayed fluorescence polymer compound based on the polynorbornene main chain and the spatial heavy atom effect specifically comprises:

[0065]

[0066] In a protective gas atmosphere, a monomer represented by formula (II), a monomer represented by formula (III) and a catalyst are added to a solvent to carry out a polymerization reaction to complete the preparation of a polymer, wherein the molar ratio of the monomer represented by formula (II) to the monomer represented by formula (III) is (1-x):x, 0<x≤1.

[0067] The polymerization reaction includes firstly adding the monomer mixture and the catalyst into a first solvent, heating to 20-60° C., reacting for 0.1-2 hours, and then settling the reaction solution into a second solvent and filtering to obtain a product.

[0068] The first solvent is one of toluene, xylene, trimethylbenzene, tert-butylbenzene, tetrahydrofuran, 1,4-dioxane, and N,N-dimethylformamide; the second solvent is one of n-hexane, acetone, methanol, and ether; the catalyst is a Grubbs catalyst, preferably a second-generation or third-generation Grubbs catalyst, and further preferred are dichloro[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinyl](benzylidene)bis(3-bromopyridine)ruthenium and 1,3-bis(2,4,6-trimethylphenyl)-2-(imidazolidinyl)(dichlorobenzylidene)(tricyclohexylphosphine)ruthenium.

[0069] In the present invention, an organic electroluminescent device includes the above-mentioned multi-resonance thermally activated delayed fluorescence polymer compound based on the polynorbornene main chain and the spatial heavy atom effect, and uses it as the luminescent material of the organic electroluminescent device.

[0070] Furthermore, the organic electroluminescent device includes a substrate, an anode arranged on the substrate, an organic layer arranged on the anode, and a cathode arranged on the organic layer, wherein there is at least one organic layer, and at least one organic electroluminescent layer in the organic layer, and the organic electroluminescent layer includes one or more of the above-mentioned multiple resonance thermally activated delayed fluorescence polymer compounds based on the polynorbornene main chain and spatial heavy atom effect.

[0071] Furthermore, the substrate is made of glass or plastic with a thickness of 0.3 to 0.7 mm; the anode is a material based on hole injection, a conductive metal or a conductive metal oxide, preferably indium tin oxide; the cathode is a metal, one of calcium, magnesium, barium, aluminum, and silver, preferably aluminum.

[0072] Furthermore, the organic layer between the anode and the organic electroluminescent layer includes a hole injection layer, a hole transport layer and an electron blocking layer, and the organic layer between the organic electroluminescent layer and the cathode includes a hole blocking layer and an electron injection / transport layer.

[0073] In the present invention, the method for preparing the above-mentioned organic electroluminescent device comprises the following steps:

[0074] forming an anode on the substrate;

[0075] forming one or more organic layers on the anode, including an organic electroluminescent layer;

[0076] A cathode is formed on the organic layer.

[0077] Among them, the organic electroluminescent layer and the organic layers below it can be formed on the anode by solution spin coating, inkjet printing, offset printing or stereo printing. After the organic electroluminescent layer is formed, a hole blocking layer and an electron injection / transport layer can be formed on its surface by vacuum evaporation or spin coating; the formation method of the cathode includes but is not limited to vacuum deposition.

[0078] Compared with the prior art, the present invention adopts a multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect as a luminescent material for an organic electroluminescent device. In the polymer compound, the structural units HAU and MR-TADF containing heavy atoms are connected to non-conjugated norbornene side chains. On the one hand, the cis, exo-configuration of the norbornene skeleton can limit HAU and MR-TADF to Within this range, the molecular orbitals between the two can produce spatial interactions, and the heavy atom effect of HAU can be transmitted to the MR-TADF unit through this spatial interaction, promoting the RISC process of MR-TADF. On the other hand, the non-conjugated molecular skeleton of norbornene can avoid strong electronic coupling between the two and retain the luminescence characteristics of MR-TADF itself. It can not only enhance the RISC process of the MR-TADF unit, but also does not affect the spectral width and peak position of its luminescence spectrum, providing new support for the development of high-performance MR-TADF organic electronic light-emitting devices. At the same time, polymer materials are also more suitable for the preparation of large-area, low-cost light-emitting devices by solution processing technology. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0080] Example 1

[0081] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P1 and the monomers used are as follows:

[0082]

[0083] Under nitrogen atmosphere, 0.95mmol Mon-H-1-1, 0.02mmol Mon-MR-1-1-1 (including monomers of formula HAU-3-6 units and formula MR-1-1-1 units) and 4mL anhydrous tetrahydrofuran (THF) were added to a 10ml Schlenk bottle, 0.004mmol Gruubs second-generation catalyst (1,3-bis(2,4,6-trimethylphenyl)-2-(imidazolidinyl) (dichlorobenzylidene) (tricyclohexylphosphine) ruthenium) was dissolved in 2mL THF, added to the above reaction system through a syringe, and reacted at 25°C for 1 hour. Subsequently, 0.2mL of end-capping agent (vinyl vinyl ether) was added to the reaction system to terminate the polymerization. The above reaction solution was precipitated in 200mL acetone, filtered to obtain a polymer, and then dissolved in 100mL dichloromethane. 75mL hydrogen peroxide (10wt% aqueous solution) was added to the above solution, and the ruthenium oxide catalyst was stirred at room temperature. The organic phase was washed with anhydrous Na 2 SO 4 After drying and concentration, the catalyst was removed by separation and purification through a silica gel column (eluent: dichloromethane), and the eluate was concentrated and then precipitated in 200 mL of methanol, filtered and vacuum dried to complete the polymer purification process and obtain the target polymer. The number average molecular weight of the polymer is 253 kDa, and the dispersion index (PDI) is 1.56.

[0084] Example 2

[0085] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P2 and the monomers used are as follows:

[0086]

[0087] The preparation conditions and feed ratios of polymer P2 are consistent with those of P1. The reactant Mon-MR-1-1-1 (including monomers of formula HAU-3-6 units and formula MR-1-1-1 units) is replaced by Mon-MR-1-1-2 (including monomers of formula HAU-3-6 units and formula MR-1-1-2 units). The number average molecular weight of the obtained polymer is 362 kDa, and the PDI is 1.69.

[0088] Example 3

[0089] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P3 and the monomers used are as follows:

[0090]

[0091] The preparation conditions and feed ratio of polymer P3 were consistent with those of P1, and the reactant Mon-H-1-1 was replaced by Mon-H-1-2. The number average molecular weight of the obtained polymer was 289 kDa and the PDI was 1.53.

[0092] Example 4

[0093] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P4 and the monomers used are as follows:

[0094]

[0095] The preparation conditions and feed ratios of polymer P4 are consistent with those of P3. The reactant Mon-MR-1-1-1 (including monomers of formula HAU-3-6 units and formula MR-1-1-1 units) is replaced by Mon-MR-1-1-2 (including monomers of formula HAU-3-6 units and formula MR-1-1-2 units). The number average molecular weight of the obtained polymer is 365 kDa and PDI is 1.77.

[0096] Example 5

[0097] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P5 and the monomers used are as follows:

[0098]

[0099] The preparation conditions and feed ratio of polymer P5 were consistent with those of P1, and the reactant Mon-H-1-1 was replaced by Mon-H-4-1. The number average molecular weight of the obtained polymer was 278 kDa and the PDI was 1.81.

[0100] Example 6

[0101] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P6 and the monomers used are as follows:

[0102]

[0103] The preparation conditions and feed ratios of polymer P6 are consistent with those of P5. The reactant Mon-MR-1-1-1 (including monomers of formula HAU-3-6 units and formula MR-1-1-1 units) is replaced by Mon-MR-1-1-2 (including monomers of formula HAU-3-6 units and formula MR-1-1-2 units). The number average molecular weight of the obtained polymer is 325 kDa, and the PDI is 1.91.

[0104] Example 7

[0105] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P9 and the monomers used are as follows:

[0106]

[0107] The preparation conditions and feed ratios of polymer P9 are consistent with those of P5. The reactant Mon-MR-1-1-1 (including monomers of formula HAU-3-6 units and formula MR-1-1-1 units) is replaced by Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 342 kDa, and the PDI is 1.68.

[0108] Example 8

[0109] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P10 and the monomers used are as follows:

[0110]

[0111] The preparation conditions and feed ratios of polymer P10 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-3-6 (including monomers of formula HAU-4-8 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 326 kDa and the PDI is 1.43.

[0112] Example 9

[0113] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P11 and the monomers used are as follows:

[0114]

[0115] The preparation conditions and feed ratios of polymer P11 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-5-8 (including monomers of formula HAU-5-8 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 269 kDa and the PDI is 1.52.

[0116] Example 10

[0117] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P20 and the monomers used are as follows:

[0118]

[0119] The preparation conditions and feed ratio of polymer P20 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-5-1. The number average molecular weight of the obtained polymer was 253 kDa and the PDI was 1.47.

[0120] Embodiment 11

[0121] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P21 and the monomers used are as follows:

[0122]

[0123] The preparation conditions and feed ratio of polymer P21 were consistent with those of P9, and the reactant Mon-H-5-1 was replaced by Mon-H-6-1. The number average molecular weight of the obtained polymer was 272 kDa and the PDI was 1.68.

[0124] Example 12

[0125] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P21 and the monomers used are as follows:

[0126]

[0127] The preparation conditions and feed ratio of polymer P24 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-5-13. The number average molecular weight of the obtained polymer was 283 kDa and the PDI was 1.52.

[0128] Embodiment 13

[0129] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P28 and the monomers used are as follows:

[0130]

[0131] The preparation conditions and feed ratio of polymer P28 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-4-12. The number average molecular weight of the obtained polymer was 276 kDa and the PDI was 1.62.

[0132] Embodiment 14

[0133] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P30 and the monomers used are as follows:

[0134]

[0135] The preparation conditions and feed ratio of polymer P30 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-4-3. The number average molecular weight of the obtained polymer was 275 kDa and the PDI was 1.68.

[0136] Embodiment 15

[0137] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P31 and the monomers used are as follows:

[0138]

[0139] The preparation conditions and feed ratio of polymer P31 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-4-2. The number average molecular weight of the obtained polymer was 326 kDa and the PDI was 1.76.

[0140] Example 16

[0141] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P33 and the monomers used are as follows:

[0142]

[0143] The preparation conditions and feed ratio of polymer P33 were consistent with those of P9, and the reactant Mon-H-4-1 was replaced by Mon-H-4-16. The number average molecular weight of the obtained polymer was 429 kDa and the PDI was 1.96.

[0144] Embodiment 17

[0145] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P55 and the monomers used are as follows:

[0146]

[0147] The preparation conditions and feed ratios of polymer P55 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-24-1 (including monomers of formula HAU-3-6 units and formula MR-1-24-1 units). The number average molecular weight of the obtained polymer is 231 kDa and the PDI is 1.43.

[0148] Embodiment 18

[0149] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula of which is P64 and the monomers used are as follows:

[0150]

[0151] The preparation conditions and feed ratios of polymer P64 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-48-2 (including monomers of formula HAU-3-6 units and formula MR-1-48-2 units). The number average molecular weight of the obtained polymer is 251 kDa and the PDI is 1.76.

[0152] Embodiment 19

[0153] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P71 and the monomers used are as follows:

[0154]

[0155] The preparation conditions and feed ratios of polymer P71 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-8 (including monomers of formula HAU-3-6 units and formula MR-1-1-8 units). The number average molecular weight of the obtained polymer is 302 kDa and PDI is 1.58.

[0156] Embodiment 20

[0157] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula of which is P74 and the monomers used are as follows:

[0158]

[0159] The preparation conditions and feed ratios of polymer P74 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-51-1 (including monomers of formula HAU-3-6 units and formula MR-1-51-1 units). The number average molecular weight of the obtained polymer is 263 kDa and PDI is 1.52.

[0160] Embodiment 21

[0161] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula of which is P78 and the monomers used are as follows:

[0162]

[0163] The preparation conditions and feed ratios of polymer P78 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-8-1 (including monomers of formula HAU-8-1 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 321 kDa and the PDI is 1.65.

[0164] Embodiment 22

[0165] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula of which is P47 and the monomers used are as follows:

[0166]

[0167] The preparation conditions and feed ratios of polymer P47 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-6-4 (including monomers of formula HAU-6-4 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 336 kDa, and the PDI is 1.83.

[0168] Embodiment 23

[0169] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P43 and the monomers used are as follows:

[0170]

[0171] The preparation conditions and feed ratios of polymer P73 are consistent with those of P9. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-7-2 (including monomers of formula HAU-7-2 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 298 kDA and PDI is 1.65.

[0172] Embodiment 24

[0173] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula of which is P79 and the monomers used are as follows:

[0174]

[0175] Under nitrogen atmosphere, 1.00mmol Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) and 4mL anhydrous tetrahydrofuran (THF) were added to a 10ml Schlenk bottle. 0.004mmol Gruubs second-generation catalyst (1,3-bis(2,4,6-trimethylphenyl)-2-(imidazolidinyl) (dichlorobenzylidene) (tricyclohexylphosphine) ruthenium) was dissolved in 2mL THF and added to the above reaction system via a syringe, and reacted at 25°C for 1 hour. Subsequently, 0.2mL of end-capping agent (vinyl vinyl ether) was added to the reaction system to terminate the polymerization. The above reaction solution was precipitated in 200mL acetone, filtered to obtain a polymer, and then dissolved in 100mL dichloromethane. 75mL hydrogen peroxide (10wt% aqueous solution) was added to the above solution, and the ruthenium oxide catalyst was stirred at room temperature. The organic phase was filtered through anhydrous Na 2 SO 4 After drying and concentration, the catalyst was removed by separation and purification through a silica gel column (eluent: dichloromethane), and the eluate was concentrated and then precipitated in 200 mL of methanol, filtered and vacuum dried to complete the polymer purification process and obtain the target polymer. The number average molecular weight of the polymer is 275 kDa, and the dispersion index (PDI) is 1.66.

[0176] Embodiment 25

[0177] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula P81 and the monomers used are as follows:

[0178]

[0179] The preparation conditions and feed ratios of polymer P81 are consistent with those of P79. The reactant Mon-MR-1-1-4 (including monomers of formula HAU-3-6 units and formula MR-1-1-4 units) is replaced by Mon-MR-1-1-4-7-2 (including monomers of formula HAU-7-2 units and formula MR-1-1-4 units). The number average molecular weight of the obtained polymer is 343 kDa and the PDI is 1.71.

[0180] Comparative Example 1

[0181] A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, the structural formula and the monomers used are as follows:

[0182]

[0183] The preparation conditions and feed ratios of polymer Ctrl-P1 are consistent with those of P9. The reactant Mon-MR-1-1-4 (a monomer comprising HAU-3-6 units and MR-1-1-4 units) is replaced by Ctrl-MR-1-1-4 (a monomer comprising only MR-1-1-4 multiple resonance thermally activated delayed fluorescence units). The number average molecular weight of the obtained polymer is 325 kDa and the PDI is 1.72.

[0184] Embodiment 26

[0185] The specific device structure used is ITO / PEDOT:PSS / EML (~50nm) / TSPO1 / TmPyPB / LiF / Al, where ITO, PEDOT:PSS, TSPO1, TmPyPB, LiF, and Al are anode, hole injection layer, hole blocking layer, electron transport layer, electron injection layer, and cathode, respectively.

[0186]

[0187] The device preparation process includes: spin coating poly (3,4-ethylenedioxythiophene) - poly (styrene sulfonic acid) (PEDOT:PSS) on indium tin oxide supported on a glass substrate, annealing at 120 ° C for 30 minutes, then spin coating a toluene solution (8 mg / ml) containing the polymer compound of the present invention at 1500 rpm for 60 seconds, and annealing at 100 ° C for 30 minutes to form a 40 nm light-emitting layer on the PEDOT:PSS, and then at 4×10 -4 TSPO1, TmPyPB and LiF / Al cathode were deposited in sequence under a vacuum degree of Pa to obtain an organic electroluminescent device. Its performance parameters are shown in Table 1.

[0188] Table 1 Performance parameters of organic electroluminescent devices obtained from device examples

[0189]

[0190] Note: Half-peak width is the peak width at half the peak height of the electroluminescence spectrum at room temperature; Turn-on voltage is the value at which the brightness is 1 cd m -2 The maximum external quantum efficiency is obtained according to the current-voltage curve and electroluminescence spectrum of the device according to the calculation method described in the literature (Jpn. J. Appl. Phys. 2001, 40, L783).

[0191] It can be seen from the data shown in Table 1 that based on the same multiple resonance thermally activated delayed fluorescence unit, compared with the polymer compound (Ctrl-P1) not containing a heavy atom structural unit, the multiple resonance thermally activated delayed fluorescence polymer electroluminescence peak position and spectral width based on the polynorbornene main chain and spatial heavy atom effect provided by the present invention do not change significantly, and are in the range of 481-485nm and 21-23nm, respectively, indicating that the non-conjugated norbornene skeleton can avoid the strong electronic coupling between the heavy atom structural unit and the MR-TADF unit at its side.

[0192] More noteworthy is that the multi-resonance thermally activated delayed fluorescence polymer compound based on the polynorbornene main chain and the spatial heavy atom effect provided by the present invention has a high brightness (1000 cd / m 2 The above phenomenon can be attributed to the fact that the structural unit containing heavy atoms in the polymer compound provided by the present invention can promote the reverse intersystem crossing process of the multiple resonance thermally activated delayed fluorescence unit on the polymer through spatial interaction, reduce the delayed fluorescence lifetime, slow down the device efficiency roll-off, and achieve further improvement of device performance.

[0193] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect, characterized in that: Its molecular formula is shown in formula (I): Wherein, 0<x≤1, n is an integer from 2 to 9999; is a structural unit containing a heavy atom, wherein the atomic number of the heavy atom is greater than 13, is a multiple resonance thermally activated delayed fluorescence unit, is a main unit, selected from any one of the following groups formed by lacking a hydrogen atom in formulas H-1 to H19: Among them, the dotted line indicates bonding or non-bonding. K is selected from one of B, N, and R3-P=O, Q1, Q2 and Q3 are each independently selected from R4-C-R5, R6-Si-R7, R8-Ge-R9, R 10 -B, R 11 - one of P=O, R3-P, O, S, Se, Te, C=O, O=S=O, R1~R 11 Each is independently selected from H, halogen, -CN, -NO2, substituted or unsubstituted C1-C22 straight-chain alkyl, substituted or unsubstituted C1-C22 branched alkyl, substituted or unsubstituted C1-C22 cycloalkyl, substituted or unsubstituted C1-C22 alkoxy chain, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a fusion of the above groups; or R1-R 11 They can be connected by chemical bonds to form a bridge structure.

2. The polymer compound according to claim 1, characterized in that: The main unit is selected from any one of the following groups formed by lacking a hydrogen atom in formulas H-1-1 to H-19-1:

3. The polymer compound according to claim 1, characterized in that: The unit containing heavy atoms is selected from any one of the following formulas HAU-1 to HAU-8: Among them, the dotted line indicates bonding or non-bonding; K is selected from one of B, N, and R3-P=O; Q4, Q5 and Q6 are each independently selected from one of R4-Si-R5, R6-Ge-R7, S, Se, Te; R1 to R7 in formulas HAU-1 to HAU-8 are each independently selected from H, halogen, -CN, -NO2, substituted or unsubstituted C1 to C22 straight chain alkyl, substituted or unsubstituted C1 to C22 branched alkyl, substituted or unsubstituted C1 to C22 cycloalkyl, substituted or unsubstituted C1 to C22 alkoxy chain, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C3 to C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a condensation of the above groups; or R1 to R7 can be connected by chemical bonds to form a bridge structure.

4. The polymer compound according to claim 3, characterized in that: The unit containing a heavy atom is selected from any one of the groups formed by lacking a hydrogen atom in the following formulas HAU-1-1 to HAU-8-1:

5. The polymer compound according to claim 1, characterized in that: The multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1 to MR-4: Wherein, G1 to G2 are each independently selected from non-bonded, single-bonded, BR 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 , R 1 -P=O, C=O, S=O, O=S=O, O, S, Se or Te; M1~M4 are selected from BR 1 NR 1 , PR 1 , R 1 -P=O, C=O, S=O, O=S=O, O, S, Se or Te; K1-K2 are each independently selected from B, N, P, P=O; BR in G1~G2 and M1~M4 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 are each independently selected from substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl; or said BR 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 is connected to one or two of the adjacent A1 to A5 via a linker or a single bond; or the BR 1 , R 1 -CR 2 , R 1 -Si-R 2 NR 1 , PR 1 With R 1 -P=R in O 1 and R 2 It is bonded to one or two adjacent M1-M4 via a linking group or a single bond; A1-A5 are each independently selected from a C6-C60 aromatic ring or a C3-C60 aromatic heterocyclic ring.

6. The polymer compound according to claim 5, characterized in that: A1 to A5 in the multiple resonance thermally activated delayed fluorescence unit are each independently selected from any one of the following formulas 1 to 53: Wherein, L1, L2 and L3 are each independently selected from: (i) H, halogen, -CN, -NO2, OH; (ii) a straight chain, branched chain or cycloalkyl or alkoxy chain containing 1 to 30 carbon atoms, wherein one or more non-adjacent carbon atoms may be substituted by O, S, Si, -CO-O-, and one or more hydrogen atoms may be substituted by halogen; (iii) a substituted or unsubstituted C6~C60 aryl group or C5~C60 heteroaryl group; L1, L2 and L3 may be connected by chemical bonds to form a bridge structure.

7. The polymer compound according to claim 6, characterized in that: The multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1-1 to MR-4-6: Among them, R1~R 12 Each is independently selected from H, halogen, -CN, -NO2, substituted or unsubstituted C1-C22 straight-chain alkyl, substituted or unsubstituted C1-C22 branched alkyl, substituted or unsubstituted C1-C22 cycloalkyl, substituted or unsubstituted C1-C22 alkoxy chain, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, a group formed by a combination of the above groups, or a group formed by a fusion of the above groups; or R1-R 12 They are connected by chemical bonds to form a bridge structure.

8. The polymer compound according to claim 7, characterized in that: The multiple resonance thermally activated delayed fluorescence unit is selected from any one of the following formulas MR-1-1-1 to MR-4-5-1:

9. The multi-resonance thermally activated delayed fluorescence polymer compound based on the polynorbornene main chain and the spatial heavy atom effect according to any one of claims 1 to 8, characterized in that: The preparation method comprises: In a protective gas atmosphere, a monomer represented by formula (II), a monomer represented by formula (III) and a catalyst are added to a solvent to carry out a polymerization reaction to complete the preparation of a polymer, wherein the molar ratio of the monomer represented by formula (II) to the monomer represented by formula (III) is (1-x):x, 0<x≤1.

10. An organic electroluminescent device, comprising the multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect as claimed in any one of claims 1 to 8, or the multi-resonance thermally activated delayed fluorescence polymer compound based on a polynorbornene main chain and a spatial heavy atom effect obtained by the preparation method of claim 9, characterized in that: The polymer compound is used as the luminescent material of an organic electroluminescent device.

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