A non-conjugated polymer thermally excited delayed fluorescence material, preparation method and application thereof

Abstract

The non-conjugated polymer TADF material provided by the present invention utilizes the donor-acceptor in the para position of styrene to better realize the spatial charge transfer between chains and realize thermally excited delayed fluorescence. The present invention rationally designs the molecular structure and synthesis route of the non-conjugated polymer TADF material, gives full play to the charge donor-acceptor characteristics of the substituent group, adjusts the emission wavelength of the light-emitting device, and thus realizes the controllable luminescent color. The electroluminescent device prepared by using the non-conjugated polymer TADF material prepared by the present invention as the light-emitting layer material has good comprehensive performance, and the molecular synthesis process and the preparation process of the electroluminescent device can realize controllable preparation, which is conducive to the promotion and application of the non-conjugated polymer TADF material.

Description

Technical Field

[0001] The invention belongs to the technical field of electroluminescence, and in particular relates to a non-conjugated polymer thermally excited delayed fluorescence material. Background Art

[0002] In recent years, organic light-emitting diode (OLED) displays have attracted widespread attention due to their advantages, including high power efficiency, excellent color reproduction, and the ability to achieve flexible displays. To improve the efficiency of OLEDs, thermally excited delayed fluorescence (TADF) materials have been the most widely studied. The design mechanism of this type of material is to use donors and acceptors to construct a charge transfer excited state system. When the donor and acceptor have a large torsion angle, the HOMO and LUMO orbitals are almost completely separated, resulting in a small singlet-triplet energy difference, thus achieving efficient TADF properties. In addition, polymer materials have attracted much attention due to their advantages such as low preparation cost, easy solution processing, excellent flexibility and ductility, and the ability to tune electronic properties through structural design and appropriate synthetic strategies. However, most light-emitting polymers with charge transfer (CT) characteristics are based on conjugated DA structures and emit through bond charge transfer (TBCT). Although their emission color and excited state energy levels can be tuned, they will produce a large red shift, which is not conducive to blue light emission, and there is a contradiction between ΔEST and PLQY.

[0003] Therefore, it is necessary to design polymer space charge transfer (TSCT) TADF luminescent materials with strong charge transfer, small ΔEST and high PLQY, and to make polymer materials with push-pull electron units to realize space charge transfer and adjust the luminescence color. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a non-conjugated polymer thermally excited delayed fluorescent material based on phenylacridine and phenylphosphinooxy substituents (or phenylphosphinooxy triazine substituents), which is a non-conjugated polymer with phenylacridine groups as transfer charge donors and phenylphosphinooxy groups followed by phenylphosphinooxy triazine groups as transfer charge acceptors, forming a spatial charge transfer to achieve a smaller triplet energy difference (ΔE ST ), improves the fluorescence quantum yield (PLQY), avoids red shift, and improves the luminescence quality and overall performance. The invention is obtained by polymerizing styrene with acridine substituents and phenyltriazine substituents. The preparation method is easy to carry out, thereby completing the present invention.

[0005] The first aspect of the present invention aims to provide a non-conjugated polymer thermally excited delayed fluorescence material, which is a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents or phenylacridine and phenylphosphinooxytriazine substituents, and is a polymer obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxy substituents as monomers, or is a polymer obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxytriazine substituents as monomers.

[0006] The second aspect of the present invention is to provide a method for preparing the non-conjugated polymer thermally excited delayed fluorescent material, which is obtained by polymerizing styrene with an acridinium-type substituent and styrene with a phenylphosphinooxy-type substituent as monomers, or by polymerizing styrene with an acridinium-type substituent and styrene with a phenyltriazine-type substituent as monomers. The method specifically comprises the following steps:

[0007] Step 1, preparing styrene with acridine substituents;

[0008] Step 2, preparing styrene with phenylphosphinoyl substituents;

[0009] Alternatively, step 2', preparing styrene with phenylphosphinooxytriazine substituents;

[0010] Step 3: preparing a non-conjugated copolymer thermally excited delayed fluorescent material by addition reaction.

[0011] The third aspect of the present invention aims to provide a use of the non-conjugated polymer thermally excited delayed fluorescent material in preparing an electroluminescent device, wherein the non-conjugated polymer thermally excited delayed fluorescent material is used as a light-emitting layer material.

[0012] A fourth aspect of the present invention provides an electroluminescent device prepared from the non-conjugated polymer thermally excited delayed fluorescent material. The light-emitting layer material of the electroluminescent device includes one or more of a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents and a non-conjugated copolymer based on phenylacridine and phenylphosphinooxytriazine substituents.

[0013] The non-conjugated polymer thermally excited delayed fluorescent material and the preparation method thereof provided by the present invention have the following beneficial effects:

[0014] (1) The present invention uses styrene with acridine substituents as a charge donor and introduces styrene with phenylphosphinooxy substituents and styrene with phenylphosphinooxy triazine substituents as acceptors to prepare non-conjugated polymers with different monomer ratios. The use of the acceptor and the donor in the para position of styrene can better achieve interchain spatial charge transfer. In addition, by introducing the electron-withdrawing ability of different acceptors and regulating the steric hindrance effect of different polymer ratios, thermally excited delayed fluorescence can be achieved, resulting in a high external quantum efficiency. Among them, the external quantum efficiency of the light-emitting device prepared from the copolymer including PVP-0.92DMAC-0.08PhTzDPPO units can reach 32.4%.

[0015] (2) The non-conjugated polymer TADF material of the present invention utilizes the electron induction effect of phenylacridine, phenylphosphinooxy, or phenylphosphinooxytriazine substituents in the copolymer, as well as the polymerization of different donor-acceptor ratios to regulate the interaction between the donor and acceptor. While ensuring high luminous efficiency, it maintains efficient blue and green light emission, which has a driving effect on the construction of efficient polymer organic electroluminescent devices.

[0016] (3) The present invention rationally designs the molecular structure and synthesis route of the non-conjugated polymer TADF material to obtain a styrene comonomer with a phenylacridine substituent, a phenylphosphinooxy substituent or a phenylphosphinooxytriazine substituent, giving full play to the charge donor-acceptor characteristics of the substituent group, adjusting the emission wavelength of the light-emitting device, thereby realizing controllable preparation of the luminescent color.

[0017] (4) The electroluminescent device prepared by using the non-conjugated polymer TADF material prepared by the present invention as the light-emitting layer material has a low turn-on voltage, high current efficiency and power efficiency, and effectively improved external quantum efficiency. The prepared electroluminescent device has good comprehensive performance, and the molecular synthesis process and the preparation process of the electroluminescent device can achieve controllable preparation, which is conducive to the promotion and application of the non-conjugated polymer TADF material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The UV fluorescence spectrum of the copolymer product I PVP-0.93DMAC-0.07DPPO synthesized in Example 4 is shown, wherein the ■ curve represents the UV absorption spectrum of the copolymer product I film, and the ● curve represents the fluorescence emission spectrum of the copolymer product I film;

[0019] Figure 2 The thermogravimetric analysis spectrum of the copolymer product I PVP-0.93DMAC-0.07DPPO synthesized in Example 4 is shown;

[0020] Figure 3FIG2 shows the ultraviolet fluorescence spectrum of the copolymer product II PVP-0.87DMAC-0.13DPPO synthesized in Example 5, wherein the ■ curve represents the ultraviolet absorption spectrum of the PVP-0.87DMAC-0.13DPPO film, and the ● curve represents the fluorescence emission spectrum of the PVP-0.87DMAC-0.13DPPO film;

[0021] Figure 4 The thermogravimetric analysis spectrum of the copolymer product II PVP-0.87DMAC-0.13DPPO synthesized in Example 5 is shown;

[0022] Figure 5 The UV fluorescence spectrum of the copolymer III PVP-0.82DMAC-0.18DPPO synthesized in Example 6 is shown, wherein the ■ curve represents the UV absorption spectrum of the PVP-0.82DMAC-0.18DPPO film, and the ● curve represents the fluorescence emission spectrum of the PVP-0.82DMAC-0.18DPPO film;

[0023] Figure 6 The thermogravimetric analysis spectrum of the copolymer product III PVP-0.80DMAC-0.20DPPO synthesized in Example 6 is shown;

[0024] Figure 7 The transient photoluminescence decay curves of the PVP-0.93DMAC-0.07DPPO film synthesized in Example 4 are shown. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K.

[0025] Figure 8 The transient photoluminescence decay curves of the PVP-0.87DMAC-0.13DPPO film synthesized in Example 5 are shown. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K.

[0026] Figure 9 The transient photoluminescence decay curves of the PVP-0.80DMAC-0.20DPPO film synthesized in Example 6 are shown. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K.

[0027] Figure 10The voltage-current density relationship curve of the blue TADF device prepared in Example 7 is shown, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0028] Figure 11 The voltage-brightness relationship curve of the blue light TADF device prepared in Example 7 is shown, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0029] Figure 12 The brightness-current efficiency relationship curve of the blue TADF device prepared in Example 7 is shown, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0030] Figure 13 The brightness-power efficiency relationship curve of the blue TADF device prepared in Example 7 is shown, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0031] Figure 14 The brightness-external quantum efficiency relationship curve of the blue light TADF device prepared in Example 7 is shown, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0032] Figure 15The electroluminescence curve of the blue TADF device prepared in Example 7 is shown in the figure, with the ◆ curve representing the device based on PVP-0.93DMAC-0.07DPPO and the The curve represents a device based on PVP-0.87DMAC-0.13DPPO, using The curve represents the device based on PVP-0.80DMAC-0.20DPPO;

[0033] Figure 16 The ultraviolet fluorescence spectrum of the copolymer product IV PVP-0.95DMAC-0.05PhTzDPPO synthesized in Example 8 is shown, wherein the ■ curve represents the ultraviolet absorption spectrum of PVP-0.95DMAC-0.05PhTzDPPO, and the ● curve represents the fluorescence emission spectrum of PVP-0.95DMAC-0.05PhTzDPPO;

[0034] Figure 17 The thermogravimetric analysis spectrum of the copolymer product IV PVP-0.95DMAC-0.05PhTzDPPO synthesized in Example 8 is shown;

[0035] Figure 18 The ultraviolet fluorescence spectrum of copolymer V PVP-0.92DMAC-0.08PhTzDPPO synthesized in Example 9 is shown, wherein the ■ curve represents the ultraviolet absorption spectrum of PVP-0.92DMAC-0.08PhTzDPPO, and the ● curve represents the fluorescence emission spectrum of PVP-0.92DMAC-0.08PhTzDPPO;

[0036] Figure 19 The thermogravimetric analysis spectrum of copolymer V PVP-0.92DMAC-0.08PhTzDPPO synthesized in Example 9 is shown;

[0037] Figure 20 The UV fluorescence spectrum of the copolymer VI PVP-0.83DMAC-0.17PhTzDPPO synthesized in Example 10 is shown, wherein the UV absorption spectrum of PVP-0.83DMAC-0.17PhTzDPPO is represented by the ■ curve, and the fluorescence emission spectrum of PVP-0.83DMAC-0.17PhTzDPPO is represented by the ● curve;

[0038] Figure 21 The thermogravimetric analysis spectrum of the copolymer VI PVP-0.83DMAC-0.17PhTzDPPO synthesized in Example 10 is shown;

[0039] Figure 22The transient photoluminescence decay curves of the PVP-0.95DMAC-0.05PhTzDPPO film synthesized in Example 8 are shown, with the ■ curve representing the decay curve at 77K, the ● curve representing the decay curve at 100K, the ▲ curve representing the decay curve at 200K, and the ▼ curve representing the decay curve at 300K.

[0040] Figure 23 The transient photoluminescence decay curves of the PVP-0.92DMAC-0.08PhTzDPPO film synthesized in Example 9 are shown. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K.

[0041] Figure 24 The transient photoluminescence decay curves of the PVP-0.83DMAC-0.17PhTzDPPO film synthesized in Example 10 are shown. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K.

[0042] Figure 25 The voltage-current density relationship curve of the green light TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curve represents the device based on PVP-0.83DMAC-0.17PhTzDPPO;

[0043] Figure 26 The voltage-brightness relationship curve of the green light TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curve represents the device based on PVP-0.83DMAC-0.17PhTzDPPO;

[0044] Figure 27 The brightness-current efficiency relationship curve of the green TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curve represents the device based on PVP-0.83DMAC-0.17PhTzDPPO;

[0045] Figure 28 The brightness-power efficiency relationship curve of the green TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curve represents the device based on PVP-0.83DMAC-0.17PhTzDPPO;

[0046] Figure 29 The brightness-external quantum efficiency relationship curve of the green light TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curve represents the device based on PVP-0.83DMAC-0.17PhTzDPPO;

[0047] Figure 30 The electroluminescence curve of the green TADF device prepared in Example 11 is shown, with the ◆ curve representing the device based on PVP-0.95DMAC-0.05PhTzDPPO and the The curve represents a device based on PVP-0.92DMAC-0.08PhTzDPPO, with The curves represent devices based on PVP-0.83DMAC-0.17PhTzDPPO. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below through specific embodiments, and the features and advantages of the present invention will become clearer and more distinct with these descriptions.

[0049] The present invention provides a non-conjugated polymer thermally excited delayed fluorescence material based on phenylacridine and phenylphosphinooxy or phenylacridine and phenylphosphinooxytriazine substituents. The material is obtained by polymerizing styrene with an acridine substituent and styrene with a phenylphosphinooxy substituent (or phenylphosphinooxytriazine substituent). The non-conjugated polymer, which uses phenylacridine groups as charge donors and phenylphosphinooxy groups or phenylphosphinooxytriazine substituents as charge acceptors, can better achieve interchain spatial charge transfer. By introducing the electron-withdrawing ability of different acceptors and the steric hindrance effect of the DPPO group to regulate different polymer ratios, thermally excited delayed fluorescence can be achieved, resulting in a higher external quantum efficiency and improving the luminescence quality and overall performance of the device.

[0050] The non-conjugated polymer thermally excited delayed fluorescent material provided in the first aspect of the present invention is a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents or phenylacridine and phenylphosphinooxytriazine substituents, which is a polymer obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxy substituents as monomers, or a polymer obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxy triazine substituents as monomers.

[0051] The styrene with an acridinium substituent is selected from para-acridine-substituted styrene or meta-acridine-substituted styrene, preferably para-acridine-substituted styrene. The acridinium substituent is selected from N-9,9-dialkyl-acridinyl, with a specific structure as shown in formula (1-1), R1 and R2 are each independently selected from an alkyl group containing C1-C8 carbon atoms, preferably an alkyl group containing C1-C3 carbon atoms, such as methyl, ethyl, propyl or isopropyl, and more preferably methyl.

[0052]

[0053] The styrene with phenylphosphinooxy substituents is selected from para-phenylphosphinooxy substituted styrene or meta-phenylphosphinooxy substituted styrene, preferably para-phosphinooxy substituted styrene, more preferably 4-diphenylphosphinooxy-styrene.

[0054] The styrene with phenylphosphinooxy triazine substituents is selected from para- or meta-phenylphosphinooxy triazine substituents, preferably para-phenylphosphinooxy triazine substituents, and more preferably 4-(2-phenyl-4-diphenylphosphinooxy-1,3,5-triazinyl)-styrene (as shown in formula (2)).

[0055]

[0056] In a preferred embodiment of the present invention, the polymer comprises the following structural units:

[0057]

[0058] Wherein, R1 and R2 are each independently selected from an alkyl group containing C1-C8 carbon atoms, preferably an alkyl group containing C1-C3 carbon atoms, such as methyl, ethyl, propyl or isopropyl, more preferably methyl; the ratio of a to b is (70-110):(5-30), preferably (75-100):(5-25), more preferably (80-95):(5-20).

[0059] Preferably, the polymer comprises one of the following structural units:

[0060]

[0061]

[0062] More preferably, the polymer comprises the following structural units:

[0063]

[0064] The non-conjugated polymer thermally excited delayed fluorescent material is a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents or phenylacridine and phenylphosphinooxytriazine substituents, obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxy substituents as monomers, or by polymerizing styrene with acridine substituents and styrene with phenyltriazine substituents as monomers. The method specifically comprises the following steps:

[0065] Step 1, preparing styrene with acridine substituents;

[0066] Step 2, preparing styrene with phenylphosphinoyl substituents;

[0067] Alternatively, step 2', preparing styrene with phenylphosphinooxytriazine substituents;

[0068] Step 3: preparing a non-conjugated copolymer thermally excited delayed fluorescent material by addition reaction.

[0069] The present invention uses styrene with acridine substituents as a charge donor and introduces styrene with phenylphosphinooxy substituents and phenylphosphinotriazine substituents as acceptors to prepare non-conjugated polymers with varying monomer ratios. The use of the acceptor and donor in the para position of the styrene allows for better interchain charge transfer. Furthermore, by incorporating different acceptor electron-withdrawing capabilities and steric hindrance effects to regulate the polymer ratios, thermally excited delayed fluorescence can be achieved, resulting in a high external quantum efficiency. A light-emitting device prepared from a copolymer comprising PVP-0.92DMAC-0.08PhTzDPPO units can achieve an external quantum efficiency of 32.4%.

[0070] The non-conjugated polymer TADF material of the present invention utilizes the electron induction effect of phenylacridine, phenylphosphinooxy, or phenylphosphinotriazine substituents in the copolymer, as well as the polymerization of different donor-acceptor ratios to modulate the interaction between the donor and acceptor. While ensuring high luminous efficiency, it also maintains efficient blue and green light emission, potentially advancing the construction of efficient polymer organic electroluminescent devices.

[0071] A second aspect of the present invention provides a method for preparing the non-conjugated polymer thermally excited delayed fluorescent material, which is obtained by polymerizing styrene with an acridine-type substituent and styrene with a phenylphosphinooxy-type substituent as monomers, or by polymerizing styrene with an acridine-type substituent and styrene with a phenyltriazine-type substituent as monomers. The method specifically comprises the following steps:

[0072] Step 1: Prepare styrene with acridine substituents.

[0073] The styrene with acridine substituents is specifically as described in the first aspect.

[0074] Monohalogenated styrene and 9,9-dialkylacridine are added to a solvent, and heated to react in a protective atmosphere in the presence of a catalyst to prepare the styrene with acridine substituents.

[0075] The monohalogenated styrene is selected from p-halogenated styrene or m-halogenated styrene, preferably p-halogenated styrene, and the halogenated styrene is selected from iodinated, brominated or chloro, preferably brominated or chloro, more preferably brominated.

[0076] In the 9,9-dialkylacridine, the alkyl groups are each independently selected from an alkyl group containing C1-C8 carbon atoms, preferably an alkyl group containing C1-C3 carbon atoms, such as methyl, ethyl, propyl or isopropyl, more preferably methyl.

[0077] The molar ratio of the monohalogenated styrene to the 9,9-dialkylacridine is 1:(0.6-1.6), preferably 1:(0.8-1.4), and more preferably 1:(1-1.2).

[0078] The solvent is selected from one or more of aromatic hydrocarbon solvents, such as toluene and xylene, ether solvents, such as tetrahydrofuran and ethylene glycol monomethyl ether, and amide solvents, such as N,N-dimethylformamide and N,N-dimethylacetamide, preferably one or more of toluene, xylene, N,N-dimethylformamide and N,N-dimethylacetamide, more preferably toluene.

[0079] The molar volume ratio of the monohalogenated styrene to the solvent is 1 mmol:(1-5) mL, preferably 1 mmol:(1.5-4) mL, and more preferably 1 mmol:(2-3) mL.

[0080] The catalyst is selected from palladium catalysts, such as palladium salts, palladium carbon, and palladium complexes, preferably one or more of palladium salts and / or palladium complexes, such as palladium acetate, Pd(AsPh3)4, Pd(n-Bu3P)4, Pd((MeO)3P)4, tris-(dibenzylideneacetone)dipalladium, tetrakis(triphenylphosphine)palladium, more preferably palladium acetate or tetrakis(triphenylphosphine)palladium. Preferably, the ligand compound added to the catalyst is preferably a phosphorus ligand, more preferably tri-tert-butylphosphine; the molar ratio of the ligand compound to the palladium in the catalyst is (2.5-4):1, preferably (3-3.5):1.

[0081] The molar ratio of the monohalogenated styrene to the catalyst is 1:(0.01-0.04), preferably 1:(0.015-0.035), more preferably 1:(0.02-0.03), and the molar amount of the catalyst is calculated based on the molar amount of palladium therein.

[0082] Preferably, the reaction is carried out under alkaline conditions. An alkaline substance is added to the reaction solution, wherein the alkaline substance is selected from one or more of alkali metal hydroxides, potassium alkoxides, and sodium alkoxides, preferably one or more of potassium alkoxides and sodium alkoxides, and more preferably potassium tert-butoxide and / or sodium tert-butoxide.

[0083] The molar ratio of the monohalogenated styrene to the alkaline substance is 1:(0.6-1.8), preferably 1:(0.8-1.5), and more preferably 1:(1-1.2).

[0084] The protective atmosphere is nitrogen and / or argon, such as argon. The reaction temperature is 105-145°C, preferably 115-135°C; and the reaction time is 8-16 hours, preferably 11-13 hours.

[0085] After the reaction is completed, the reaction solution is poured into deionized water for post-treatment. The reaction solution is extracted, the organic phase is separated and dried, the solvent is removed, and the product is purified to obtain styrene with acridine substituents.

[0086] The extraction comprises adding an extraction solvent to the reaction solution, wherein the extraction solvent is selected from one or more halogenated alkane solvents, such as dichloromethane; combining the organic layers and drying them with a desiccant (such as anhydrous Na2SO4), and then spin-drying; and purifying the crude product by flash column chromatography using a mixed solvent of petroleum ether and dichloromethane.

[0087] Step 2, preparing styrene with phenylphosphinoyl substituents;

[0088] Under a protective atmosphere, halogenated styrene, phenyl phosphorus halide compounds and metallic magnesium are added to a solvent and reacted at low temperature. After the reaction is completed, the reaction liquid is poured into water, extracted, washed, dried, and the solvent is removed. After oxidation, purification is performed to obtain styrene with phenylphosphinooxy substituents.

[0089] The halogenated styrene is selected from p-halogenated styrene or m-halogenated styrene, preferably p-halogenated styrene, and the halogenated styrene is selected from bromo, chloro or fluoro, preferably bromo or chloro, more preferably bromo. In a preferred embodiment of the present invention, the halogenated styrene is selected from p-bromostyrene, p-chlorostyrene, m-bromostyrene or m-chlorostyrene, preferably p-bromostyrene, p-chlorostyrene, more preferably p-bromostyrene.

[0090] The phenyl phosphorus halide compound is selected from phenyl phosphorus dihalide or diphenyl phosphorus halide, preferably diphenyl phosphorus chloride and diphenyl phosphorus bromide, more preferably diphenyl phosphorus chloride.

[0091] The molar ratio of the halogenated styrene to the phenyl phosphorus halide compound is 1:(0.8-1.8), preferably 1:(1.0-1.5), and more preferably 1:(1.1-1.3).

[0092] The molar ratio of the halogenated styrene to the magnesium metal is 1:(0.6-1.8), preferably 1:(0.8-1.5), more preferably 1:(1.0-1.2).

[0093] The solvent is selected from one or more of ether solvents, alcohol solvents or phenol solvents, preferably one or more of ether solvents, more preferably tetrahydrofuran.

[0094] The molar volume ratio of the halogenated styrene to the solvent is 1 mmol:(1-6) mL, preferably 1 mmol:(1.5-5) mL, and more preferably 1 mmol:(2-4) mL.

[0095] The reaction temperature is -70 to -95°C, preferably -75 to -85°C; the reaction time is 8 to 18 hours, preferably 10 to 15 hours.

[0096] The extraction is performed using a halogenated hydrocarbon solvent, preferably a halogenated hydrocarbon solvent having a carbon number of C1-C3, more preferably dichloromethane. After extraction, the mixture is washed with water, and after separation, the organic phase is separated.

[0097] The drying step involves drying the organic phase with a desiccant, which is a solid desiccant that is chemically inert to the solvent and the phenylphosphinooxy-substituted styrene at room temperature, such as anhydrous sodium sulfate. The solvent removal step involves rotary evaporation at normal pressure or under reduced pressure.

[0098] The oxidation is carried out by conventional methods to obtain phenylphosphinoyl groups, such as oxidation with a hydrogen peroxide solution. The purification is performed by column chromatography, preferably using a mixed solvent of petroleum ether and ethyl acetate as an eluent. The protective atmosphere is nitrogen and / or argon, such as argon.

[0099] Alternatively, step 2', preparing styrene with phenylphosphinooxytriazine substituents;

[0100] The preparation process of the styrene with phenylphosphinooxy triazine substituents comprises: adding 2-halogenated-4-phenyl-6-vinylphenyl-1,3,5-triazine and diphenylphosphine hydrogen to a reaction solvent under a protective atmosphere, and heating the reaction; after the reaction stops, pouring the reaction solution into water, extracting, washing with water, and drying the organic phase, removing the solvent, oxidizing, and purifying to obtain the styrene with phenylphosphinooxy triazine substituents.

[0101] The 2-halogenated 4-phenyl-6-vinylphenyl-1,3,5-triazine is selected from 2-halogenated 4-phenyl-6-p-vinylphenyl-1,3,5-triazine or 2-halogenated 4-phenyl-6-m-vinylphenyl-1,3,5-triazine, wherein the halogenated is selected from bromo, chloro or fluoro, preferably bromo or chloro, more preferably chloro.

[0102] The molar ratio of the 2-halogenated-4-phenyl-6-vinylphenyl-1,3,5-triazine to diphenylphosphine is 1:(1.2-2.8), preferably 1:(1.6-2.5), and more preferably 1:(2.0-2.2).

[0103] The reaction solvent is selected from one or more of ether solvents, amide solvents or phenol solvents, preferably one or more of amide solvents, more preferably N,N-dimethylformamide and / or N,N-dimethylacetamide.

[0104] The molar volume ratio of the 2-halogenated-4-phenyl-6-vinylphenyl-1,3,5-triazine to the solvent is 1 mmol:(1-5) mL, preferably 1 mmol:(1.5-4) mL, and more preferably 1 mmol:(2-3) mL.

[0105] The reaction temperature is 80-120° C., preferably 90-110° C.; the reaction time is 8-18 hours, preferably 10-15 hours.

[0106] The extraction is performed using a halogenated hydrocarbon solvent, preferably a halogenated hydrocarbon solvent having a carbon number of C1-C3, more preferably dichloromethane. After extraction, the mixture is washed with water, and after separation, the organic phase is separated.

[0107] The drying step involves drying the organic phase with a desiccant, which is a solid desiccant that is chemically inert to the solvent and the phenylphosphinooxytriazine-substituted styrene at room temperature, such as anhydrous sodium sulfate. The solvent removal step involves rotary evaporation at normal pressure or under reduced pressure.

[0108] The oxidation is carried out by conventional methods to obtain phenylphosphinoyl groups, such as oxidation with a hydrogen peroxide solution. The purification is performed by column chromatography, preferably using a mixed solvent of petroleum ether and ethyl acetate as an eluent. The protective atmosphere is nitrogen and / or argon, such as argon.

[0109] Step 3: preparing a non-conjugated copolymer thermally excited delayed fluorescent material by addition reaction.

[0110] In a protective atmosphere, the polymerization monomer is added to the polymerization solvent, and the reaction is heated. After the reaction is completed, a crystallization solvent is added, and the non-conjugated copolymer thermally excited delayed fluorescent material is obtained after purification.

[0111] The polymerization is the copolymerization of styrene with acridine substituents and styrene with phenylphosphinooxy substituents, or the copolymerization of styrene with acridine substituents and styrene with phenylphosphinooxy triazine substituents.

[0112] The molar ratio of the styrene with acridine substituents to the styrene with phenylphosphinooxy substituents is (70-110):(5-30), preferably (75-100):(6-25), more preferably (80-93):(7-20), such as 93:7, 87:13, and 82:18.

[0113] The molar ratio of the styrene with acridine substituents to the styrene with phenylphosphinooxytriazine substituents is (70-110):(5-30), preferably (75-100):(5-24), more preferably (83-95):(5-17), such as 95:5, 92:8, 83:17.

[0114] The polymerization solvent is selected from one or more of ether solvents, amide solvents or phenol solvents, preferably one or more of tetrahydrofuran, N,N-dimethylformamide and N,N-dimethylacetamide, more preferably tetrahydrofuran.

[0115] The molar volume ratio of the styrene with acridine substituents to the polymerization solvent is (70-110):(0.6-4) mL, preferably (75-100) mmol:(0.8-3) mL, and more preferably (80-95) mmol:(1-2) mL.

[0116] The reaction temperature is 65-95° C., preferably 75-85° C.; the reaction time is 35-60 h, preferably 45-50 h.

[0117] The crystallization solvent is one or more ketone solvents, preferably acetone and / or butanone, more preferably cold acetone, wherein the temperature of the cold acetone is lower than 5°C.

[0118] The purification is preferably performed by Soxhlet extraction, and the protective atmosphere is nitrogen and / or argon, such as argon.

[0119] The third aspect of the present invention provides use of the non-conjugated polymer thermally excited delayed fluorescent material in preparing an electroluminescent device, wherein the non-conjugated polymer thermally excited delayed fluorescent material is used as a light-emitting layer material.

[0120] A fourth aspect of the present invention provides an electroluminescent device prepared from the non-conjugated polymer thermally excited delayed fluorescent material. The light-emitting layer material of the electroluminescent device includes one or more of a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents and a non-conjugated copolymer based on phenylacridine and phenylphosphinooxytriazine substituents.

[0121] The electroluminescent device comprises a substrate layer, a conductive anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an exciton blocking layer, an electron transport layer, an electron injection layer and a cathode conductive layer.

[0122] The electroluminescent device prepared from the non-conjugated polymer thermally excited delayed fluorescent material is prepared by a method comprising the following steps:

[0123] 1. preparing a conductive anode layer;

[0124] The conductive anode layer is formed on the substrate layer. The conductive anode layer is selected from tin oxide conductive glass (ITO), a transparent conductive polymer such as polyaniline, and a semi-transparent metal such as Au. ITO or a semi-transparent metal is preferred, and ITO is more preferred. Preferably, the conductive anode layer is deposited using a vacuum evaporation method.

[0125] Preferably, the vacuum degree of vacuum evaporation is 1×10-5 ~5×10 -5 mbar, the evaporation rate is set to 0.1-0.3 nm / s, the evaporation material is indium tin oxide on the glass or plastic substrate, and the thickness of the anode conductive layer is 60-170 nm, preferably 80-160 nm, and more preferably 100-150 nm.

[0126] Preferably, the following hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer and cathode conductive layer are prepared by vacuum evaporation method.

[0127] 2. preparing a hole injection layer;

[0128] The hole injection layer is evaporated on the anode conductive layer, and the thickness of the evaporated layer is 40 to 80 nm, preferably 45 to 75 nm, more preferably 50 to 70 nm, such as 60 nm.

[0129] The hole injection layer material is selected from molybdenum oxide or a mixture of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS), preferably a mixture of PEDOT and PSS.

[0130] 3. preparing a light-emitting layer;

[0131] The light-emitting layer is continuously evaporated on the hole injection layer, and the evaporation thickness is 15-60 nm, preferably 20-50 nm, more preferably 25-40 nm, such as 30 nm.

[0132] The light-emitting layer material includes one or more non-conjugated polymers based on phenylacridine and phenyltriazine substituents.

[0133] 4. preparing an exciton blocking layer;

[0134] The exciton blocking layer is evaporated on the light-emitting layer, and the thickness of the evaporated layer is 2-20 nm, preferably 5-10 nm, such as 5 nm.

[0135] The hole transport layer material is selected from 9,9'-(1,3-phenyl)di-9H-carbazole (mCP) or bis[2-((oxy)diphenylphosphino)phenyl]ether (DPEPO), preferably DPEPO.

[0136] 5. preparing an electron transport layer;

[0137] The electron transport layer is one or more of TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene), TmPyPb (3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]dipyridine), Bphen (4,7-diphenyl-1,10-phenanthroline) and DBFDPO (dibenzofuran-4,6-bis(diphenylphosphine oxide), preferably TPBi.

[0138] The electron transport layer is evaporated on the exciton blocking layer, and the thickness of the evaporated layer is 25-55 nm, preferably 30-50 nm, more preferably 35-45 nm, such as 40 nm.

[0139] 7. preparing an electron injection layer;

[0140] The electron injection layer is evaporated on the electron transport layer, and the thickness of the evaporated layer is 1-15 nm, preferably 1-10 nm, more preferably 1-5 nm, such as 1 nm.

[0141] The electron injection layer material is selected from lithium tetrakis(8-hydroxyquinoline)borate (LiBq4) or LiF, preferably LiF.

[0142] 8. Prepare a cathode conductive layer, encapsulate, and obtain a thermally excited delayed fluorescence electroluminescent device.

[0143] The cathode conductive layer is evaporated on the electron injection layer, and the evaporated thickness is 70-130 nm, preferably 80-120 nm, more preferably 90-110 nm, such as 100 nm.

[0144] The cathode conductive layer material is selected from a single metal cathode or an alloy cathode, such as metal Al.

[0145] The present invention provides a non-conjugated polymer thermally excited delayed fluorescence material based on phenylacridine and phenylphosphinooxy or phenylacridine and phenylphosphinooxytriazine substituents. The non-conjugated polymer uses phenylacridine groups as charge donors and phenylphosphinooxy groups or phenylphosphinooxytriazine substituents as charge acceptors, thereby better achieving interchain spatial charge transfer. By introducing the electron-withdrawing ability of different acceptors and regulating the steric hindrance effect of DPPO groups to control different proportions of polymers, thermally excited delayed fluorescence can be achieved, and the luminescent color can be controlled, thereby obtaining a higher external quantum efficiency and improving the luminescent quality and overall performance of the device.

[0146] Example

[0147] Example 1

[0148] 1 mmol of p-bromostyrene, 1 mmol of 9,9-dimethylacridine, 0.025 mmol of palladium acetate, 1.1 mmol of potassium tert-butoxide, and 0.075 mmol of tri-tert-butylphosphine were added to 2 mL of toluene solution and mixed. The mixture was reacted at 120-130°C under argon protection for 12 hours. After the reaction, the reaction solution was poured into deionized water and extracted with dichloromethane. The organic layer was washed three times with deionized water, dried over anhydrous Na2SO4, and spin-dried. The crude product was separated and purified by column chromatography using a mixture of petroleum ether and dichloromethane (volume ratio of the two was 6:1) as the eluent to obtain 9,9-dimethyl-10-(4-vinylphenyl)-9,10-dihydroacridine (VP-DMAC), the structure of which is as follows:

[0149]

[0150] Example 2

[0151] Under argon, 1 mmol of p-bromostyrene, 1.2 mmol of diphenylphosphine chloride, and 24 mg (approximately 1 mmol) of magnesium were added to 3 mL of anhydrous tetrahydrofuran and allowed to react at -78°C for 12 hours. After the reaction ceased, the reaction solution was poured into water and extracted with dichloromethane. The organic layer was then washed three times with water, dried over anhydrous Na₂SO₄, and spin-dried. The product was then oxidized with 0.2 mL of H₂O₂ (added with an 8.8 mmol / mL aqueous hydrogen peroxide solution). The product was then purified by column chromatography using a mixture of petroleum ether and ethyl acetate (1:2 by volume) as the eluent to obtain intermediate compound I (VP-DPPO), the structure of which is shown below.

[0152]

[0153] Example 3

[0154] (1) 1 mmol of 4-vinylbenzeneboronic acid, 1 mmol of 2,4-dichloro-6-phenyl-1,3,5-triazine, 0.05 mmol of tetrakis(triphenylphosphine)palladium, 2 mmol of potassium carbonate, and 1.7 ml of water were added to 2 ml of tetrahydrofuran solution and stirred. The mixture was reacted at 80°C for 12 hours under argon protection and stirring.

[0155] After the reaction was completed, the reaction solution was poured into deionized water and extracted with dichloromethane. The organic layer was washed three times with water, dried over anhydrous Na2SO4, and spin-dried. The crude product was separated and purified by column chromatography using a mixture of petroleum ether and dichloromethane (volume ratio of 10:1) as eluent to obtain the product 2-chloro-4-phenyl-6-(4-vinylphenyl)-1,3,5-triazine, the structure of which is as follows:

[0156]

[0157] (2) Under argon protection, 1 mmol of 2-chloro-4-phenyl-6-(4-vinylphenyl)-1,3,5-triazine and 2 mmol of diphenylphosphine were added to 2 ml of N'N-dimethylformamide (DMF) and reacted at 100°C for 12 hours. After the reaction stopped, the reaction solution was poured into water and extracted with dichloromethane. The organic layer was washed three times with water, dried over anhydrous Na2SO4, and spin-dried. It was then oxidized with 1 mL of H2O2 (added with 8.8 mmol / ml of hydrogen peroxide solution) and purified by column chromatography using a mixture of petroleum ether and ethyl acetate (volume ratio of 1:1) as the eluent to obtain intermediate compound II (VP-PhTzDPPO), the specific structure of which is shown below.

[0158]

[0159] Example 4

[0160] 0.95 mmol of VP-DMAC, 0.05 mmol of VP-DPPO and 0.02 mmol of azobisisobutyronitrile (AIBN) were added to 2 ml of anhydrous tetrahydrofuran and reacted at 80°C for 48 hours under argon protection. Cold acetone was added to precipitate the product, and Soxhlet extraction was performed for 48 hours to obtain the target product, i.e., the addition copolymerization product I of VP-DMAC and VP-DPPO.

[0161] The H NMR spectrum data of the obtained copolymerization product I are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 7.740-6.902 (m, 7H), 6.790-6.537 (m, 4H), 6.272-6 .007(m,2H),2.829-2.254(m,1H),2.171-1.720(m,2H),1.699-1.341ppm(m,7H).

[0162] The product was subjected to gel permeation chromatography (GPC) test, and the molecular weight of the polymer was found to be 18539, and the molecular weight distribution index (PDI) was 1.5. 1 Calculated by H NMR. Find the characteristic peak (2H) of the donor (diphenylacridine group) monomer, then subtract the number of characteristic peaks (2H) and monomer aromatic hydrogens (10H) from the total number of aromatic hydrogens in the polymer (7+4+2=13H). The remaining hydrogen number (1H) is then divided by the aromatic hydrogens of the acceptor (diphenylphosphine oxide group) (14H). The ratio of donor to acceptor in the polymer is approximately 0.93:0.07. The calculation method is the same in subsequent examples. It can be seen that copolymer product I has the following structural units:

[0163]

[0164] The ultraviolet fluorescence spectrum of the copolymerization product I obtained in this example is as follows Figure 1 shown.

[0165] The thermogravimetric analysis spectrum of the copolymerization product I obtained in this example is as follows Figure 2 As shown in the figure, it can be seen that the cracking temperature of copolymer product Ⅰ reaches 376℃.

[0166] The copolymer product I was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0167] Figure 7 This is the transient photoluminescence decay curve of the thin film prepared from copolymer product I. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime changes slightly, which proves its TADF property. The polymer has good contrast as a control sample.

[0168] Example 5

[0169] Copolymer II was prepared according to the method of Example 4, except that 0.90 mmol of VP-DMAC and 0.10 mmol of VP-DPPO were added.

[0170] The H NMR spectrum data of the obtained copolymer product II are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 7.677-6.839 (m, 8H), 6.781-6.537 (m, 4H), 6.270-5 .979(m,2H),2.686-2.198(m,1H),2.140-1.698(m,2H),1.698-1.244ppm(m,7H).

[0171] Gel chromatography (GPC) analysis of the product revealed a molecular weight of 31138 and a molecular weight distribution index (PDI) of 1.8. Therefore, the copolymer II had the following structural units:

[0172]

[0173] The ultraviolet fluorescence spectrum of the copolymer product II obtained in this example is as follows Figure 3 shown.

[0174] The thermogravimetric analysis spectrum of the copolymer product II obtained in this example is as follows Figure 4 As shown in the figure, it can be seen that the cracking temperature of copolymer product II reaches 393℃.

[0175] The copolymer product II was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0176] Figure 8 This is the transient photoluminescence decay curve of the thin film prepared from copolymer product II. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime changes slightly, which proves its TADF property. The polymer has good contrast as a control sample.

[0177] Example 6

[0178] Copolymer III was prepared according to the method of Example 4, except that 0.80 mmol of VP-DMAC and 0.20 mmol of VP-DPPO were added.

[0179] The H NMR spectrum data of the obtained copolymer product III are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 7.751-6.841 (m, 9H), 6.793-6.541 (m, 4H), 6.338-5 .883(m,2H),2.734-2.208(m,1H),2.148-1.717(m,2H),1.717-1.274ppm(m,7H).

[0180] Gel chromatography (GPC) analysis of the product revealed a molecular weight of 17760 and a molecular weight distribution index (PDI) of 1.4. Therefore, the copolymer III has the following structural units:

[0181]

[0182] The ultraviolet fluorescence spectrum of the copolymer product III obtained in this example is as follows Figure 5 shown.

[0183] The thermogravimetric analysis spectrum of the copolymer product III obtained in this example is as follows Figure 6 As shown in the figure, it can be seen that the cracking temperature of copolymer product III reaches 391℃.

[0184] The copolymer product III was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0185] Figure 9This is the transient photoluminescence decay curve of the thin film prepared from the copolymer product III. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime changes significantly, proving its TADF properties.

[0186] Example 7

[0187] Copolymer products I, II, and III prepared in Examples 4, 5, and 6 were used to prepare blue light TADF devices, respectively, and the preparation was specifically carried out according to the following steps:

[0188] 1. Place the glass or plastic substrate cleaned with deionized water into the vacuum evaporator with a vacuum degree of 5×10 - 5 mbar, and the evaporation rate was set to 0.1–0.3 nm s -1 , on a glass or plastic substrate, an anode conductive layer with a thickness of 150nm is deposited using indium tin oxide as the material;

[0189] 2. Spin-coat a 60nm thick hole injection layer made of a mixture of PEDOT and PSS (where the mass fraction of PEDOT is 5%) on the anode conductive layer;

[0190] 3. Spin-coating the copolymer I, copolymer II or copolymer III on the hole injection layer to obtain a light-emitting layer with a thickness of 30 nm;

[0191] 4. Continue to evaporate an exciton blocking layer DPEPO with a thickness of 5 nm on the light-emitting layer;

[0192] 5. Evaporating an electron transport layer with a thickness of 40 nm and TPBi on the exciton blocking layer;

[0193] 6. Evaporate LiF on the electron transport layer to form an electron injection layer with a thickness of 1 nm;

[0194] 7. A cathode conductive layer with a thickness of 100 nm and a metal Al material is evaporated on the electron injection layer, and then encapsulated to obtain an organic electroluminescent device based on a non-conjugated polymer TADF material.

[0195] The voltage-current density relationship curve of the blue light TADF device prepared with copolymer product I, copolymer product II or copolymer product III in this embodiment is shown in FIG. Figure 10 As shown, the curve ◆ represents the device based on the copolymerization product Ⅰ (PVP-0.93DMAC-0.07DPPO), and the curve ◆ represents the device based on the copolymerization product Ⅰ (PVP-0.93DMAC-0.07DPPO). The curve represents the device based on copolymer product II (PVP-0.87DMAC-0.13DPPO), The curve represents the device based on copolymer III (PVP-0.82DMAC-0.18DPPO). The figure shows that the turn-on voltage of the device based on copolymer I is 6.8V; the turn-on voltage of the device based on copolymer II is 6.6V; and the turn-on voltage of the device based on copolymer III is 5.8V.

[0196] The voltage-brightness relationship curve of the blue light TADF device prepared with copolymer product I, copolymer product II or copolymer product III in this embodiment is shown in FIG. Figure 11 As shown, the curve ◆ represents the device based on copolymerization product Ⅰ, and the curve The curve represents the device based on copolymer II, The curve represents the device based on copolymer product III. From this figure, it can be seen that the brightness of the device based on copolymer product I, copolymer product II or copolymer product III reaches a maximum value of 41 cd·m -2 、38cd·m -2 、33cd·m -2 .

[0197] The brightness-current efficiency relationship curve of the blue light TADF device prepared with copolymer product I, copolymer product II or copolymer product III in this embodiment is shown in FIG. Figure 12 As shown, the curve ◆ represents the device based on copolymerization product Ⅰ, and the curve The curve represents the device based on copolymer II, The curve represents the device based on copolymer product III. From this figure, it can be seen that the current efficiency of the device based on copolymer product I, copolymer product II or copolymer product III reaches a maximum value of 9.48 cd·A respectively. -1 、12.46cd·A -1 、12.95cd·A -1 .

[0198] The brightness-power efficiency relationship curve of the blue light TADF device prepared by copolymerization product I, copolymerization product II or copolymerization product III in this embodiment is shown in FIG. Figure 13 As shown, the curve ◆ represents the device based on copolymerization product Ⅰ, and the curve The curve represents the device based on copolymer II, The curve represents the device based on copolymer III. From this figure, it can be seen that the power efficiency of the device based on copolymer I, copolymer II or copolymer III reaches a maximum of 4.3 lm·W respectively. -1 、6.5lm·W -1 , 5.9lm·W -1 .

[0199] The brightness-external quantum efficiency relationship curve of the blue light TADF device prepared based on copolymerization product I, copolymerization product II or copolymerization product III in this embodiment is as follows: Figure 14 As shown, the curve ◆ represents the device based on copolymerization product Ⅰ, and the curve The curve represents the device of copolymerization product II. The curve represents the device based on copolymer III. From this figure, it can be seen that the external quantum efficiency of the device based on copolymer I, copolymer II or copolymer III reaches a maximum value of 6.4%, 8.1% and 8.2% respectively.

[0200] The electroluminescence spectrum curve of the blue light TADF device prepared by copolymerization product I, copolymerization product II or copolymerization product III in this embodiment is as follows: Figure 15 As shown, the curve ◆ represents the device based on copolymerization product Ⅰ, and the curve The curve represents the device of copolymerization product II. The curve represents the device based on copolymer III. From this figure, it can be seen that the electroluminescence peaks of the device based on copolymer I, copolymer II or copolymer III are 425nm, 426nm and 430nm respectively.

[0201] Example 8

[0202] 0.95 mmol of VP-DMAC, 0.05 mmol of VP-PhTzDPPO and 0.02 mmol of azobisisobutyronitrile (AIBN) were added to 2 ml of anhydrous tetrahydrofuran and reacted at 80°C for 48 hours under argon protection. Cold acetone was added to precipitate the product, and Soxhlet extraction was performed for 48 hours to obtain the target product, i.e., the addition copolymerization product IV of VP-DMAC and VP-PhTzDPPO.

[0203] The H NMR spectrum data of the obtained copolymer product IV are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 8.528-8.181 (m, 4H), 7.958-7.759 (m, 4H), 7.412-6.917 (m, 142H), 6.817-6.4 94(m,88H),6.297-5.974(m,43H),2.727-2.306(m,20H),2.132-1.711(m,41H),1.637-1.215ppm(m,138H).

[0204] The product was subjected to gel permeation chromatography (GPC) test, and the molecular weight of the polymer was found to be 26610 and the molecular weight distribution index PDI was 1.6. 1H NMR calculations were performed. The characteristic peak (8H) of the acceptor (phenyltriazine group) monomer was found, and then the number of characteristic peaks (8H) and monomer aromatic hydrogens (11H) was subtracted from the total number of aromatic hydrogens in the polymer (4+4+142+88+43=281H). The remaining hydrogen number (262H) was then divided by the aromatic hydrogens (12H) of the donor (phenylacridine group). The ratio of donor units to acceptor units was approximately 0.95:0.05. The calculation method used in the subsequent examples was the same. It can be seen that copolymer IV has the following structural units:

[0205]

[0206] The ultraviolet fluorescence spectrum of the copolymerized product IV obtained in this example is as follows Figure 16 shown.

[0207] The thermogravimetric analysis spectrum of the copolymer product IV obtained in this example is as follows Figure 17 As shown in the figure, it can be seen that the cracking temperature of the copolymer product IV reaches 390℃.

[0208] The copolymer product IV was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0209] Figure 22 This is the transient photoluminescence decay curve of the thin film prepared from the copolymer product IV. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime becomes shorter, which proves that it has TADF properties. The ratio of transient fluorescence to delayed fluorescence can be calculated.

[0210] Example 9

[0211] Copolymer V was prepared according to the method of Example 8, except that 0.90 mmol VP-DMAC and 0.10 mmol VP-PhTzDPPO were added.

[0212] The H NMR spectrum data of the obtained copolymerization product V are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 8.546-8.174 (m, 4H), 7.957-7.723 (m, 4H), 7.380-6.885 (m, 77H), 6.825-6.4 69(m,46H),6.308-5.927(m,22H),2.699-2.229(m,11H),2.080-1.709(m,20H),1.659-1.163ppm(m,73H).

[0213] Gel chromatography (GPC) analysis of the product revealed a molecular weight of 29598 and a molecular weight distribution index (PDI) of 1.7. Therefore, the copolymerization product V has the following structural units:

[0214]

[0215] The ultraviolet fluorescence spectrum of the copolymerization product V obtained in this example is as follows Figure 18 shown.

[0216] The thermogravimetric analysis spectrum of the copolymerization product V obtained in this example is as follows Figure 19 As shown in the figure, it can be seen that the cracking temperature of the copolymer product V reaches 394℃.

[0217] The copolymer product V was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0218] Figure 23 This is the transient photoluminescence decay curve of the thin film prepared from the copolymer product V. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime becomes significantly shorter, which proves that it has good TADF properties. In addition, the ratio of transient fluorescence to delayed fluorescence can be calculated.

[0219] Example 10

[0220] Copolymer VI was prepared according to the method of Example 9, except that 0.80 mmol VP-DMAC and 0.20 mmol VP-PhTzDPPO were added.

[0221] The H NMR spectrum data of the obtained copolymerization product VI are as follows: 1 H NMR (TMS, CDCl3, 400MHz): δ = 8.553-8.160 (m, 4H), 7.971-7.693 (m, 4H), 7.448-6.903 (m, 38H), 6.794-6. 428(m,20H),6.301-5.732(m,10H),2.788-2.192(m,5H),2.144-1.746(m,9H),1.672-1.003ppm(m,33H).

[0222] Gel chromatography (GPC) analysis of the product revealed a molecular weight of 26067 and a molecular weight distribution index (PDI) of 1.4. Therefore, the copolymer VI has the following structural units:

[0223]

[0224] The ultraviolet fluorescence spectrum of the copolymerization product VI obtained in this example is as follows Figure 20 shown.

[0225] The thermogravimetric analysis spectrum of the copolymerization product VI obtained in this example is as follows Figure 21 As shown in the figure, it can be seen that the cracking temperature of the copolymer product VI reaches 395℃.

[0226] The copolymer product VI was prepared into a film, and the transient photoluminescence decay curve of the polymer film was tested.

[0227] Figure 24 This is the transient photoluminescence decay curve of the thin film prepared from the copolymer product VI. The ■ curve represents the decay curve at a temperature of 77K, the ● curve represents the decay curve at a temperature of 100K, the ▲ curve represents the decay curve at a temperature of 200K, and the ▼ curve represents the decay curve at a temperature of 300K. It can be seen from the figure that with the increase of temperature, the lifetime becomes shorter, which proves its TADF nature. The ratio of transient fluorescence to delayed fluorescence can be calculated.

[0228] Example 11

[0229] Following the method of Example 7, copolymers IV, V, and VI prepared in Examples 8, 9, and 10 were used to prepare green TADF devices, respectively. The only difference was that copolymers IV, V, and VI were spin-coated on the hole injection layer to form the light-emitting layer.

[0230] The voltage-current density relationship curves of green light TADF devices prepared with copolymers IV, V and VI are shown in Figure 2. Figure 25 As shown, the curve ◆ represents the device based on the copolymer product IV PVP-0.95DMAC-0.05PhTzDPPO, and the curve ◆ represents the device based on the copolymer product IV PVP-0.95DMAC-0.05PhTzDPPO. The curve represents the device based on the copolymer product VPVP-0.92DMAC-0.08PhTzDPPO, with The curve represents a device based on copolymer VI PVP-0.83DMAC-0.17PhTzDPPO. The figure shows that the turn-on voltages of devices based on copolymers IV, V, and VI are 4.2 V, 3.4 V, and 3.4 V, respectively. This indicates that as the acceptor ratio increases, the charge transfer between the donor and acceptor is enhanced, and the turn-on voltage decreases. The lower turn-on voltage compared to the diphenylphosphine oxide system (Example 7) also indicates a significant increase in the charge interaction between the donor and acceptor.

[0231] The voltage-brightness relationship curves of green light TADF devices prepared with copolymers IV, V and VI are shown in Figure 2. Figure 26As shown, the curve ◆ represents the device based on the copolymer product IV, and the curve The curve represents the device based on copolymer product V, The curve represents the device based on copolymer VI. From this figure, it can be seen that the brightness of the devices based on copolymer IV, copolymer V and copolymer VI reaches a maximum of 1543 cd·m -2 、2186cd·m -2 、2478cd·m -2 .

[0232] The brightness-current efficiency relationship curve of the green light TADF device prepared based on copolymer product IV, copolymer product V and copolymer product VI is shown in FIG. Figure 27 As shown, the curve ◆ represents the device based on the copolymer product IV, and the curve The curve represents the device based on copolymer product V, The curve represents the device based on copolymer VI. From this figure, it can be seen that the current efficiency of the devices based on copolymer IV, copolymer V and copolymer VI reaches a maximum value of 89.7 cd·A respectively. -1 、102.9cd·A -1 、47.3cd·A -1 .

[0233] In this example, the brightness-power efficiency relationship curve of the green light TADF device prepared based on copolymer product IV, copolymer product V and copolymer product VI is shown as follows: Figure 28 As shown, the curve ◆ represents the device based on the copolymer product IV, and the curve The curve represents the device of copolymerization product V, The curve represents the device based on copolymer VI. From this figure, it can be seen that the power efficiency of the devices based on copolymer IV, copolymer V and copolymer VI reaches a maximum of 67.9 lm·W respectively. -1 、92.3lm·W -1 、39.1lm·W -1 .

[0234] In this example, the brightness-external quantum efficiency relationship curve of the green light TADF device prepared based on copolymer product IV, copolymer product V and copolymer product VI is shown in FIG. Figure 29 As shown, the curve ◆ represents the device based on the copolymer product IV, and the curve The curve represents the device based on copolymer product V, The curve represents the device based on copolymer VI. The figure shows that the external quantum efficiencies of devices based on copolymers IV, V, and VI reach maximum values ​​of 28.8%, 32.4%, and 14.5%, respectively. Among them, the external quantum efficiency of the device based on copolymer V PVP-0.92DMAC-0.08PhTzDPPO is the highest value reported to date.

[0235] The electroluminescence spectrum curves of the green light TADF device prepared by copolymerization product IV, copolymerization product V and copolymerization product VI in this example are shown in FIG. Figure 30 As shown, the curve ◆ represents the device based on the copolymer product IV, and the curve The curve represents the device based on copolymer product V, The curve represents the device based on P copolymer VI. From this figure, it can be seen that the electroluminescence peaks of the devices based on copolymer IV, copolymer V and copolymer VI are 520nm, 525nm and 532nm respectively.

[0236] The present invention has been described in detail above with reference to specific embodiments and / or exemplary examples and the accompanying drawings. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A non-conjugated polymer thermally excited delayed fluorescent material, which is a polymer obtained by polymerizing styrene with acridine substituents and styrene with phenylphosphinooxy substituents as monomers. The styrene with acridine substituents is a para-acridine substituted styrene; the acridine substituent is selected from N-9,9-dialkyl-acridinyl, the specific structure of which is shown in formula (1-1), R1 and R2 are each independently selected from an alkyl group containing carbon atoms of C1-C8, The styrene with phenylphosphinooxy substituent is 4-diphenylphosphinooxy-styrene; The polymer comprises the following structural units: in, R1 and R2 are each independently selected from an alkyl group containing C1-C8 carbon atoms; The ratio of a and b is (70-110):(5-30).

2. The material according to claim 1, characterized in that R1 and R2 are each independently an alkyl group containing C1 to C3 carbon atoms.

3. The material according to claim 1, characterized in that R1 and R2 are each independently methyl, ethyl, propyl or isopropyl; The ratio of a and b is (75-100):(5-25).

4. The material according to claim 3, characterized in that R1 and R2 are each independently a methyl group; The ratio of a and b is (80-95):(5-20).

5. The material according to any one of claims 1 to 4, characterized in that The polymer comprises one of the following structural units:

6. A method for preparing the non-conjugated polymer thermally excited delayed fluorescent material according to any one of claims 1 to 5, wherein the non-conjugated polymer thermally excited delayed fluorescent material is obtained by polymerizing styrene with an acridine-type substituent and styrene with a phenylphosphinooxy-type substituent as monomers, the method specifically comprising the following steps: Step 1, preparing styrene with acridine substituents; Step 2, preparing styrene with phenylphosphinoyl substituents; Step 3: preparing a non-conjugated copolymer thermally excited delayed fluorescent material by addition reaction.

7. The method according to claim 6, characterized in that In step 1, a halogenated styrene and 9,9-dialkylacridine are added to a solvent, and heated to react in a protective atmosphere in the presence of a catalyst to prepare the styrene with an acridine substituent.

8. The method according to claim 6, characterized in that In step 2, under a protective atmosphere, halogenated styrene, phenyl phosphorus halide compounds and metallic magnesium are added to a solvent and reacted at low temperature. After the reaction is completed, the reaction solution is poured into water, extracted, washed, and dried, and the solvent is removed. After oxidation, purification is performed to obtain styrene with phenylphosphinooxy substituents.

9. Use of the non-conjugated polymer thermally excited delayed fluorescent material according to any one of claims 1 to 5 for preparing an electroluminescent device, characterized in that: The non-conjugated polymer thermally excited delayed fluorescent material is used as the light-emitting layer material.

10. An electroluminescent device prepared from the non-conjugated polymer thermally excited delayed fluorescent material according to any one of claims 1 to 5, characterized in that: The electroluminescent device comprises a substrate layer, a conductive anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an exciton blocking layer, an electron transport layer, an electron injection layer and a cathode conductive layer; The light-emitting layer material of the electroluminescent device comprises a non-conjugated copolymer based on phenylacridine and phenylphosphinooxy substituents.

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