Preparation method and application of phenothiazinyl organic polymer hole transport material

Abstract

The invention relates to the technical field of perovskite solar cells, in particular to a preparation method and application of a phenothiazinyl organic polymer hole transport material, which have the advantages of safe synthesis conditions, simple steps and cheap and easily available synthesis raw materials. Through cyclic voltammetry, compared with a mainstream hole transport material PTAA, the hole transport material provided by the invention has a more appropriate highest occupied molecular orbital energy level (-5.26 eV), and provides a strong driving force for hole transport. In addition, the contact angle between the PPTZ-OM and a perovskite precursor solution is smaller than that of PTAA, so that the PPTZ-OM is beneficial to film formation and crystallization on a perovskite layer, interface defects are effectively reduced, an inverted perovskite solar cell device can be prepared without other post-treatment, and the photoelectric conversion efficiency is 20.27%. Therefore, the PPTZ-OM has a good application potential in the PSC. Therefore, the problem of poor morphological stability of the film caused by weak intermolecular acting force of the existing micromolecular organic compound is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a preparation method and application of a phenothiazine-based organic polymer hole transport material. Background Art

[0002] Perovskite solar cells (PSCs) have attracted widespread attention in the photovoltaic field due to their excellent power conversion efficiency (PCE), simple fabrication process, and low cost. After more than a decade of development, the PCE of inverted devices has increased from 3.8% to 27%. Hole transport materials (HTMs) are essential functional layers, primarily transporting holes while protecting the perovskite light-absorbing layer from water and oxygen in the external environment, thereby effectively improving PSC device performance. Poly(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA) is one of the most widely used HTMs in inverted PSCs. However, its strong hydrophobicity requires dopants or surface post-treatment, resulting in complex and costly device fabrication, which has limited its commercialization. Therefore, the development of a simple, efficient, and low-cost HTM is highly urgent.

[0003] Phenothiazine (PTZ) contains N and S heteroatoms and can react with Pb 2+ It undergoes Lewis acid-base interaction to passivate defects in the perovskite layer, and possesses abundant modification sites and excellent electron-donating properties, making it a promising molecular framework. The methoxy group, as an electron-donating group, also possesses good hydrophilicity, effectively improving molecular wettability, reducing buried defects, and inhibiting non-radiative recombination.

[0004] Based on the above analysis, the present invention designed and prepared a phenothiazine-based polymer hole transport material, named PPTZ-OM. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of a phenothiazine-based organic polymer hole transport material, aiming to solve the problem of poor film morphological stability caused by weak intermolecular forces of existing small molecule organic compounds.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a phenothiazine-based organic polymer hole transport material, comprising the following steps:

[0007] Under argon protection, phenothiazine and 4-bromoanisole were added to toluene in sequence, stirred and dissolved, and potassium tert-butoxide, tri-tert-butylphosphine and palladium acetate were added respectively, and the temperature was raised to reflux. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained unchanged, and the reaction was stopped to obtain intermediate I;

[0008] Add intermediate I to THF and stir to dissolve, then add NBS dissolved in THF and slowly drip through a constant pressure funnel. Allow to react at room temperature in the dark. Monitor the reaction by thin layer chromatography until the concentration of the reactants remains constant, then stop the reaction to obtain intermediate II.

[0009] Under argon protection, intermediate II and pinacol diboron were sequentially added to 1,4-dioxane with stirring to dissolve, followed by the addition of potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride. The temperature was raised to reflux, and the reaction was monitored by thin-layer chromatography until the concentration of the reactants remained constant, at which point the reaction was stopped to obtain intermediate III.

[0010] Under argon protection, potassium carbonate was dissolved in a small amount of distilled water, and then intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium were added to toluene in sequence, stirred and dissolved, and the temperature was raised to 50°C for activation for 2 hours. Then, the temperature was raised to 80°C and refluxed for 72 hours. The reaction was tracked by thin layer chromatography until the concentration of the reactants remained unchanged, and the reaction was stopped to obtain the polymer PPTZ-OM.

[0011] Among them, in "under argon protection, phenothiazine and 4-bromoanisole are added to toluene in sequence, stirred and dissolved, and then potassium tert-butoxide, tri-tert-butylphosphine and palladium acetate are added respectively, the temperature is raised, the reaction is refluxed, and the reaction is tracked by thin layer chromatography until the concentration of the reactants remains unchanged, and the reaction is stopped to obtain intermediate I", the amount of phenothiazine is 1 molar part; the amount of 4-bromoanisole added is 0.83 molar parts; the amount of potassium tert-butoxide is 2.5 molar parts; the amount is 0.083 molar parts; the amount of palladium acetate is 0.042 molar parts; the heating temperature is 110°C, and the reaction reflux time is 12 h.

[0012] Among them, in “adding intermediate I to THF and stirring to dissolve, adding NBS dissolved in THF and slowly dripping it through a constant pressure funnel, reacting at room temperature in the dark, tracking the reaction by thin layer chromatography until the concentration of the reactants remains unchanged, and stopping the reaction to obtain intermediate II”, the amount of intermediate I is 1 mol part; the amount of NBS is 3 mol parts; and the reaction time for the reaction at room temperature in the dark is 6 h.

[0013] Among them, in the step of “under argon protection, adding intermediate II and bipyraclostrobin to 1,4-dioxane in sequence and stirring to dissolve, then adding potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride respectively, heating the reaction and reflux, tracking the reaction by thin layer chromatography until the concentration of the reactants remains unchanged, and then stopping the reaction to obtain intermediate III”, the amount of intermediate II is 1 mol part; the amount of bipyraclostrobin is 4.4 mol parts; the amount of potassium acetate is 6 mol parts; the amount of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride is 0.05 mol part; the heating temperature is 80°C, and the reaction reflux time is 12 h.

[0014] Among them, in "under argon protection, potassium carbonate is dissolved in a small amount of distilled water, and then intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium are added to toluene in turn, stirred and dissolved, and the temperature is raised to 50°C for activation for 2 hours, then the temperature is raised to 80°C, refluxed for 72 hours, and the reaction is tracked by thin layer chromatography until the concentration of the reactants remains unchanged, and the reaction is stopped to obtain the polymer PPTZ-OM", the amount of potassium carbonate is 4 molar parts; the amount of intermediate II is 1 molar part; the amount of intermediate III is 1 molar part; the amount of tetrakis(triphenyl)phosphine palladium is 0.01 molar part.

[0015] In the second aspect, a phenothiazine-based organic polymer hole transport material is used, which adopts the preparation method of the phenothiazine-based organic polymer hole transport material described in the first aspect and is applied to the field of perovskite solar cells.

[0016] The invention discloses a preparation method of a phenothiazine-based organic polymer hole transport material, comprising the following steps: under argon protection, sequentially adding phenothiazine and 4-bromoanisole into toluene, stirring and dissolving them, respectively adding potassium tert-butyl phosphine and palladium acetate, heating and reacting under reflux, tracking the reaction by thin-layer chromatography until the concentration of reactants remains unchanged, and then stopping the reaction to obtain an intermediate I; adding the intermediate I into THF, stirring and dissolving them, adding NBS dissolved in THF, and slowly dropping the mixture through a constant pressure funnel, reacting at room temperature in the dark, tracking the reaction by thin-layer chromatography until the concentration of reactants remains unchanged, and then stopping the reaction to obtain an intermediate II; under argon protection, sequentially adding the intermediate II into the mixture, stirring and dissolving them, and then slowly dropping the mixture through a constant pressure funnel, reacting them under room temperature and in the dark, and then tracking the reaction by thin-layer chromatography until the concentration of reactants remains unchanged, and then stopping the reaction to obtain an intermediate II. Add pinacol diboronate to 1,4-dioxane and stir to dissolve, then add potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride respectively, heat the reaction and reflux, track the reaction by thin layer chromatography until the reactant concentration remains unchanged, stop the reaction, and obtain intermediate III; under argon protection, dissolve potassium carbonate in a small amount of distilled water, then add intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium to toluene in sequence, stir and dissolve, heat to 50℃ for activation for 2h, heat to 80℃, reflux for 72h, track the reaction by thin layer chromatography until the reactant concentration remains unchanged, stop the reaction, and obtain polymer PPTZ-OM. The present invention has the advantages of safe synthesis conditions, simple steps, and cheap and readily available synthetic raw materials. Cyclic voltammetry measured that it has a more suitable highest occupied molecular orbital (HOMO) energy level (-5.26eV) than the mainstream hole transport material PTAA, providing a strong driving force for hole transport. In addition, by conducting contact angle tests separately, it can be clearly seen that the contact angle of PPTZ-OM with the perovskite precursor solution is smaller (38.3°) than that of PTAA (46.4°), which is conducive to its film crystallization in the perovskite layer, effectively reducing interface defects, and can prepare inverted perovskite solar cell (PSC) devices without other post-processing, with a photoelectric conversion efficiency of 20.27%. This shows that PPTZ-OM has good application potential in PSC. This solves the problem of poor film morphological stability caused by weak intermolecular forces of existing small molecule organic compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1The molecular structure of the polymer PPTZ-OM of Example 1 of the present invention (a phenothiazine-based polymer hole transport material, named PPTZ-OM) is shown.

[0019] Figure 2 This is a synthetic route for the polymer PPTZ-OM of Example 1 of the present invention. (In the diagram, i) 4-bromoanisole, toluene, potassium tert-butoxide, tri-tert-butylphosphine, palladium acetate, ii) tetrahydrofuran, N-bromosuccinimide, iii) pinacol diboron, 1,4-dioxane, potassium acetate, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride), iv) toluene, tetrakis(triphenyl)phosphine palladium, methanol, acetone, chloroform).

[0020] Figure 3 This is a normalized graph of the UV-visible absorption spectrum and photoluminescence spectrum of the polymer PPTZ-OM in Example 1 of the present invention (the horizontal axis is wavelength, and the vertical axis is absorbance).

[0021] Figure 4 This is a cyclic voltammogram of the polymer PPTZ-OM of Example 1 of the present invention (the horizontal axis is voltage, and the vertical axis is current).

[0022] Figure 5 Schematic diagram of the energy levels of an inverted PSC device based on the polymer PPTZ-OM in Example 1 of the present invention.

[0023] (The vertical axis is energy level).

[0024] Figure 6 This is the hydrogen nuclear magnetic resonance spectrum of intermediate I in Example 1 of the present invention. (The horizontal axis is the chemical shift).

[0025] Figure 7 This is the H NMR spectrum of Intermediate II of Example 1 of the present invention (the abscissa is the chemical shift).

[0026] Figure 8 This is the H NMR spectrum of Intermediate III of Example 1 of the present invention (the abscissa is the chemical shift).

[0027] Figure 9 The current-voltage (JV) curve of the inverted PSC device based on the polymer PPTZ-OM of Example 1 of the present invention is shown in FIG. (the abscissa is voltage, and the ordinate is current density).

[0028] Figure 10 This is a graph showing the external quantum efficiency (EQE) of an inverted PSC device based on the polymer PPTZ-OM of Example 1 of the present invention (the horizontal axis is wavelength, and the vertical axis is external quantum efficiency).

[0029] Figure 11These are the contact angle test graphs of the polymer PPTZ-OM in Example 1 of the present invention, which was spin-coated on an ITO glass substrate at 2 mg mL-1, with water and a perovskite precursor solution, respectively.

[0030] Figure 12 These are the contact angle test diagrams of PTAA spin-coated on an ITO glass substrate at 2 mg mL-1 with water and perovskite precursor solution respectively.

[0031] Figure 13 This is a solubility diagram of the polymer PPTZ-OM of Example 1 of the present invention in solvents of different polarities, such as dimethyl sulfoxide (DMSO), N,N'-dimethylformamide (DMF), toluene, and dichloromethane (DCM).

[0032] Figure 14 The present invention provides a flow chart of a method for preparing a phenothiazine-based organic polymer hole transport material. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0034] See also Figures 1 to 14 In a first aspect, the present invention provides a method for preparing a phenothiazine-based organic polymer hole transport material, comprising the following steps:

[0035] S1: Under argon protection, phenothiazine and 4-bromoanisole are added to toluene in sequence, stirred and dissolved, and potassium tert-butoxide, tri-tert-butylphosphine and palladium acetate are added respectively, and the temperature is raised to reflux. The reaction is monitored by thin layer chromatography until the concentration of the reactants remains unchanged, and the reaction is stopped to obtain intermediate I;

[0036] The amount of phenothiazine is 1 molar part; the amount of 4-bromoanisole added is 0.83 molar parts; the amount of potassium tert-butoxide is 2.5 molar parts; the amount of is 0.083 molar parts; the amount of palladium acetate is 0.042 molar parts; the heating temperature is 110°C, and the reaction reflux time is 12h.

[0037] Specifically, under argon protection, 1 mole of phenothiazine and 0.83 moles of 4-bromoanisole were added to toluene and stirred to dissolve, followed by the addition of 2.5 moles of potassium tert-butoxide, 0.083 moles of tri-tert-butylphosphine, and 0.042 moles of palladium acetate. The temperature was raised to 110°C, and the reaction was refluxed for 12 hours. The reaction was monitored by thin-layer chromatography until the concentration of the reactants remained essentially unchanged, at which point the reaction was stopped. Post-processing: The organic phase was extracted and collected, dried over anhydrous sodium sulfate, and separated by silica gel column chromatography. The product was collected to obtain a white powder, which was dried in a vacuum drying oven to constant weight to obtain Intermediate I.

[0038] S2: Add intermediate I to THF, stir and dissolve, then add NBS dissolved in THF and slowly drip through a constant pressure funnel. The reaction is carried out at room temperature in the dark. The reaction is monitored by thin layer chromatography until the concentration of the reactants remains constant, and then the reaction is stopped to obtain intermediate II.

[0039] The amount of the intermediate I is 1 mol part; the amount of the NBS is 3 mol parts; and the reaction time at room temperature and in the dark is 6 h.

[0040] Specifically, 1 mol of Intermediate I was added to THF and stirred to dissolve. Subsequently, 3 mol of NBS dissolved in THF was slowly added dropwise via a constant pressure funnel. The reaction was allowed to react at room temperature in the dark for 6 hours. The reaction was monitored by thin-layer chromatography until the concentration of the reactants remained essentially constant, at which point the reaction was stopped. Post-processing: The organic phase was extracted and collected, dried over anhydrous sodium sulfate, and separated by silica gel column chromatography. The product was collected to obtain a light yellow powder, which was then dried in a vacuum oven to constant weight to obtain Intermediate II.

[0041] S3: Under argon protection, intermediate II and pinacol diboron are sequentially added to 1,4-dioxane, stirred and dissolved, and potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride are added respectively. The temperature is raised to reflux, and the reaction is monitored by thin layer chromatography until the concentration of the reactants remains unchanged. The reaction is then stopped to obtain intermediate III.

[0042] The amount of the intermediate II is 1 mol part; the amount of the pinacol diboronate is 4.4 mol parts; the amount of potassium acetate is 6 mol parts; the amount of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride is 0.05 mol parts; the heating temperature is 80°C, and the reaction reflux time is 12 h.

[0043] Specifically, under argon protection, 1 mole of Intermediate II and 4.4 moles of diboronic acid pinacol ester were added to 1,4-dioxane and stirred to dissolve. Then, 6 moles of potassium acetate and 0.05 moles of [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride were added, respectively. The temperature was raised to 80°C, and the reaction was refluxed for 12 hours. The reaction was monitored by thin-layer chromatography until the concentration of the reactants remained essentially unchanged, at which point the reaction was stopped. Post-processing: The organic phase was extracted and collected, dried over anhydrous sodium sulfate, and separated by silica gel column chromatography. The product was collected to obtain a yellow powder (with blue fluorescence), which was dried in a vacuum drying oven to constant weight to obtain Intermediate III.

[0044] S4 Under argon protection, potassium carbonate was dissolved in a small amount of distilled water, and then intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium were added to toluene in sequence, stirred and dissolved, and the temperature was raised to 50°C for activation for 2 hours, then the temperature was raised to 80°C and refluxed for 72 hours. The reaction was tracked by thin layer chromatography until the concentration of the reactants remained unchanged, and the reaction was stopped to obtain the polymer PPTZ-OM.

[0045] The amount of potassium carbonate is 4 parts by mole; the amount of intermediate II is 1 part by mole; the amount of intermediate III is 1 part by mole; and the amount of tetrakis(triphenyl)phosphine palladium is 0.01 part by mole.

[0046] Specifically, under argon protection, 4 molar parts of potassium carbonate are dissolved in a small amount of distilled water, and then 1 molar part of intermediate II, 1 molar part of intermediate III and 0.01 molar parts of tetrakis(triphenyl)phosphine palladium are added to toluene and stirred to dissolve. The temperature is raised to 50°C for activation for 2 hours, then raised to 80°C, refluxed for 72 hours, and the reaction is tracked by thin layer chromatography until the concentration of the reactants remains essentially unchanged, and the reaction is stopped. Post-treatment: Cool to room temperature, precipitate with excess methanol, concentrate after Soxhlet extraction, and dry in a vacuum drying oven to constant weight to obtain the polymer PPTZ-OM.

[0047] Example 1:

[0048] (1) Synthesis of intermediate I: Under argon protection, phenothiazine (10 g, 50 mmol) and 4-bromoanisole (7.79 g, 41.67 mmol) were dissolved in toluene (130 mL) in a 250 mL two-necked flask and stirred on a magnetic stirrer to dissolve. Potassium tert-butoxide (12.013 g, 125.01 mmol), tri-tert-butylphosphine (0.8497 g, 4.167 mmol) and palladium acetate (0.468 g, 2.0835 mmol) were added respectively. The temperature was raised to 110°C and refluxed for 12 h. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained essentially unchanged, and then the reaction was stopped. Post-treatment: Extraction, collection of the organic phase, and drying over anhydrous sodium sulfate were performed. The product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane, v:v=50:1) with a gradient elution method to obtain a white powder. The product was dried in a vacuum oven to constant weight to afford Intermediate I (12.8 g, 83.55% yield). 1H NMR (500 MHz, Chloroform-d) δ 7.35–7.31 (d, J=8.3 Hz, 2H), 7.17–7.12 (d, J=8.2 Hz, 2H), 7.04–7.00 (m, 2H), 6.87–6.68 (m, 4H), 6.25–6.12 (d, J=8.2 Hz, 2H), 3.94–3.90 (s, 3H).

[0049] (2) Synthesis of Intermediate II: In a 250 mL two-necked flask, white powder intermediate 1 (2.2 g, 7.205 mmol) was dissolved in THF (30 mL), and then NBS (3.848 g, 21.62 mmol) was dissolved in THF (45 mL) and placed in a constant pressure funnel and slowly dripped into the two-necked flask. The reaction was allowed to proceed at room temperature in the dark for 6 hours. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained essentially unchanged, at which point the reaction was stopped. Post-treatment: Extraction was performed, the organic phase was collected and dried over anhydrous sodium sulfate, and the product was separated and purified by silica gel column chromatography (petroleum ether: dichloromethane, v:v = 50:1) with gradient elution. The product was collected to obtain a light yellow compound, which was dried in a vacuum drying oven to constant weight to obtain Intermediate II (2.0374 g, yield 61%).

[0050] 1HNMR(500MHz,Chloroform-d)δ7.29–7.23(m,2H),7.16–7.10(m,2H),7.10–7.06(t,J=2.5 Hz, 2H), 6.95–6.89 (dd, J=8.8, 2.4Hz, 2H), 6.08–6.03 (d, J=8.8Hz, 2H), 3.94–3.90 (s, 3H).

[0051] (3) Synthesis of intermediate III: Under argon protection, in a 250 mL two-necked flask, intermediate 2 (1.5 g, 3.24 mmol) and diboronic acid pinacol ester (3.82 g, 14.258 mmol) were dissolved in 1,4-dioxane (100 mL), followed by the addition of potassium acetate (1.516 g, 19.44 mmol) and [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (0.1185 g, 0.162 mmol). The temperature was raised to 80 °C and the mixture was refluxed for 12 h. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained essentially unchanged, at which point the reaction was stopped. Post-treatment: Extraction, collection of the organic phase, and drying over anhydrous sodium sulfate were performed. The product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane, v:v=50:1) using a gradient elution method to obtain a yellow powder (with blue fluorescence). The product was dried in a vacuum oven to constant weight to afford Intermediate III (1.1418 g, 63% yield). 1H NMR (500 MHz, Chloroform-d) δ 7.41–7.37 (d, J=1.5 Hz, 2H), 7.30–7.27 (d, J=2.3 Hz, 2H), 7.25–7.21 (m, 2H), 7.16–7.10 (d, J=8.6 Hz, 2H), 6.11–6.06 (d, J=8.3 Hz, 2H), 3.94–3.91 (s, 3H), 1.34–1.29 (s, 24H).

[0052] (4) Synthesis of polymer PPTZ-OM: Under argon protection, in a 250 mL two-necked flask, intermediate II (0.5 g, 1.0801 mmol) and intermediate III (0.602 g, 1.0801 mmol) were dissolved in toluene (60 mL), followed by the addition of potassium carbonate (0.5971 g, 4.32 mmol) dissolved in distilled water (5 mL), and then tetrakis(triphenyl)phosphine palladium (0.01248 g, 0.011 mmol). The temperature was raised to 50 °C for activation for 2 h, then raised to 80 °C, and refluxed for 72 h. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained essentially unchanged, at which point the reaction was stopped. Post-treatment: Cool to room temperature, pour the mixture into a 500 mL beaker, add excess methanol, and filter to obtain a solid. Repeat the operation until no solid precipitates. After drying the obtained solid, extract it with a methanol:acetone (v:v=1:1) mixed solution Soxhlet for 48 h, then with chloroform Soxhlet for 72 h. Collect the liquid phase and concentrate it. Dry it in a vacuum drying oven to constant weight to obtain the polymer PPTZ-OM.

[0053] Example 2:

[0054] The contact angle test of the synthesized PPTZ-OM and the purchased PTAA in Example 1 was completed on a contact angle meter of model Powereach, and the specific steps were as follows:

[0055] For spin coating of hole transport material: the hole transport material was spin coated on the unetched glass substrate at a concentration of 2 mg mL-1, and the spin coating program was set to 3000 rpm for 25 s-1.

[0056] Heat treatment: The spin-coated substrate was heated at 100 °C for 10 min and cooled to room temperature.

[0057] Measuring the water droplet contact angle: Use a water droplet contact angle meter to adjust the substrate to a horizontal position, add water and perovskite solution separately, and record the data and take photos.

[0058] Example 3:

[0059] The electrochemical test method of Example 1 is mainly cyclic voltammetry. The test is performed using a CHI660C electrochemical workstation using a three-electrode system: a glassy carbon electrode as the working electrode, a platinum wire Ag / AgCl as the reference electrode, and ferrocene as the reference electrode. The workstation parameters are set as follows: InitE (V) = 1.2; HighE (V) = 1.2; LowE (V) = 0; InitP / N = N; ScanRate (V / s) = 0.05; Segment = 6; SampleInterval (V) = 0.001; QuietTime (sec) = 2; Sensitivity (A / V) = 1e-5.

[0060] Example 4:

[0061] The organic hole transport material PPTZ-OM prepared in Example 1 was used to prepare perovskite solar cells according to the literature: Zhang, S.; Wu, R.; Mu, C.; Wang, Y.; Han, L.; Wu, Y.; Zhu, W.-H., Conjugated Self-Assembled Monolayer as Stable Hole-Selective Contact for Inverted Perovskite Solar Cells. ACS Materials Letters 2022, 4(10), 1976-1983. The test results are shown in Figure 5 The open circuit voltage of the perovskite solar cell is 1.104V, the short circuit current density is 22.42mAcm-2, the fill factor is 81.88%, and the photoelectric conversion efficiency is 20.27%.

[0062] Example 5:

[0063] The X-ray diffraction (XRD) test used in this invention is a Rigaku DUltima IV X-ray diffractometer. The parameters are: copper-excited alpha radiation, a 1mm divergence slit (DS), and a 0.2mm receiving slit (RS). The sampling interval is 0.2 seconds (step); and the measurement range (2θ) is 5-90°. XRD analysis can be used to evaluate the condition and crystalline strength of perovskite films deposited on the surface of hole transport materials. The test samples were obtained by spin-coating the HTM onto ITO, annealing it, and then spin-coating the perovskite active layer.

[0064] The above embodiments are only preferred implementation modes of the present invention and are only used to explain the present invention rather than to limit the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of protection of the present invention.

[0065] like Figure 4 、 5 As shown in the figure, the HOMO energy level of PPTZ-OM measured by cyclic voltammetry is -5.26 eV, which can better match the perovskite valence band compared with PTAA, which is conducive to hole transport.

[0066] like Figure 6 、 7 As shown in Figure 8, through the H NMR spectrum test and analysis, it can be seen that the intermediate of the synthesis of PPTZ-OM is consistent with the corresponding H NMR spectrum data, confirming the accuracy of the synthesized structure.

[0067] like Figure 9 、 10 As shown in Table 1, the photovoltaic performance of PPTZ-OM and its corresponding parameters can be fully understood by conducting JV curve and EQE curve tests under AM 1.5G light. The open circuit voltage (VOC) is 1.104V, the short circuit voltage (JSC) is 22.42mAcm-2 and the fill factor (FF) is 81.88%, which fully meet the requirements for the hole transport layer in the inverted perovskite solar cell device.

[0068]

[0069] Table 1

[0070] like Figure 11 、 12 As shown, by conducting contact angle tests and solubility tests respectively, it can be clearly seen that compared with PTAA, PPTZ-OM has a smaller contact angle with the perovskite precursor solution, which is conducive to the crystallization of the perovskite layer thereon. At the same time, it has better solubility in solutions of different polarities, which is conducive to solution processing. No other post-processing is required to prepare inverted perovskite solar cell devices.

[0071] like Figure 13As shown in Figure 2, the solubility of PTAA-OM was tested in solvents of different polarities, including dimethyl sulfoxide (DMSO), N,N'-dimethylformamide (DMF), toluene, and dichloromethane (DCM).

[0072] In the second aspect, a phenothiazine-based organic polymer hole transport material is used, which adopts the preparation method of the phenothiazine-based organic polymer hole transport material described in the first aspect and is applied to the field of perovskite solar cells.

[0073] Beneficial effects:

[0074] (1) The phenothiazine-based polymer hole transport material prepared in the present invention has good solubility in solvents of different polarities, such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane;

[0075] (2) The raw materials of the phenothiazine-based polymer hole transport material prepared by the present invention (phenothiazine, p-bromoanisole, etc.) are low in cost, which effectively reduces the preparation cost of HTM and is suitable for commercial application production;

[0076] (3) The phenothiazine-based polymer hole transport material prepared by the present invention has a deeper HOMO energy level, which is more compatible with the valence band of the perovskite light absorption layer;

[0077] (4) The planar spatial configuration of the phenothiazine-based polymer hole transport material prepared by the present invention can effectively enhance the "π-π" stacking between molecules, while increasing the film flatness, promoting the ideal growth of perovskite crystals thereon, and giving the device excellent efficiency and long-term stability;

[0078] (5) The phenothiazine-based polymer hole transport material prepared in the present invention has good wettability in perovskite precursor solution, and the contact angle data can be put on it (compared with PTAA) without any dopant and surface post-treatment. It can be used in inverted perovskite solar cells, which is better than the common polymer HTM on the market (taking PTAA as an example), indicating that the polymer described in the present invention has broad application prospects.

[0079] The above disclosure is only a preferred embodiment of the preparation method and application of a phenothiazine-based organic polymer hole transport material of the present invention. Of course, this cannot be used to limit the scope of the rights of the present invention. Ordinary technicians in this field can understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing a phenothiazine-based organic polymer hole transport material, characterized in that: The following steps are involved: Under argon protection, phenothiazine and 4-bromoanisole were added to toluene in sequence, stirred and dissolved, and potassium tert-butoxide, tri-tert-butylphosphine and palladium acetate were added respectively, and the temperature was raised to reflux. The reaction was monitored by thin layer chromatography until the concentration of the reactants remained unchanged, and the reaction was stopped to obtain intermediate I; Add intermediate I to THF and stir to dissolve, then add NBS dissolved in THF and slowly drip through a constant pressure funnel. Allow to react at room temperature in the dark. Monitor the reaction by thin layer chromatography until the concentration of the reactants remains constant, then stop the reaction to obtain intermediate II. Under argon protection, intermediate II and pinacol diboron were sequentially added to 1,4-dioxane with stirring to dissolve, followed by the addition of potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride. The temperature was raised to reflux, and the reaction was monitored by thin-layer chromatography until the concentration of the reactants remained constant, at which point the reaction was stopped to obtain intermediate III. Under argon protection, potassium carbonate was dissolved in a small amount of distilled water, and then intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium were added to toluene in sequence, stirred and dissolved, and the temperature was raised to 50°C for activation for 2 hours. Then, the temperature was raised to 80°C and refluxed for 72 hours. The reaction was tracked by thin layer chromatography until the concentration of the reactants remained unchanged, and the reaction was stopped to obtain the polymer PPTZ-OM.

2. The method for preparing a phenothiazine-based organic polymer hole transport material according to claim 1, wherein: In the process of "Under argon protection, phenothiazine and 4-bromoanisole are sequentially added to toluene, stirred and dissolved, potassium tert-butylphosphine, tri-tert-butylphosphine and palladium acetate are respectively added, the temperature is raised, the reaction is refluxed, and the reaction is monitored by thin-layer chromatography until the concentration of the reactants remains unchanged, thereby stopping the reaction to obtain intermediate I", the amount of phenothiazine is 1 mol part; the amount of 4-bromoanisole added is 0.83 mol parts; the amount of potassium tert-butoxide is 2.5 mol parts; the amount of palladium acetate is 0.083 mol parts; the amount of palladium acetate is 0.042 mol parts; the heating temperature is 110°C, and the reaction reflux time is 12 h.

3. The method for preparing a phenothiazine-based organic polymer hole transport material according to claim 1, wherein: In the step "Intermediate I is added to THF and stirred to dissolve, and then NBS dissolved in THF is added dropwise through a constant pressure funnel. The reaction is allowed to proceed at room temperature in the dark. The reaction is monitored by thin layer chromatography until the concentration of the reactants remains constant, and the reaction is stopped to obtain Intermediate II", the amount of Intermediate I is 1 mol part; the amount of NBS is 3 mol parts; and the reaction time is 6 h at room temperature in the dark.

4. The method for preparing a phenothiazine-based organic polymer hole transport material according to claim 1, wherein: In the process of "Under argon protection, intermediate II and pinacol diboron are sequentially added to 1,4-dioxane with stirring to dissolve, potassium acetate and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride are added respectively, the temperature is raised, the reaction is refluxed, and the reaction is tracked by thin layer chromatography until the concentration of the reactants remains unchanged, and the reaction is stopped to obtain intermediate III", the amount of intermediate II is 1 mol part; the amount of pinacol diboron is 4.4 mol parts; the amount of potassium acetate is 6 mol parts; the amount of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride is 0.05 mol part; the heating temperature is 80°C, and the reaction reflux time is 12 h.

5. The method for preparing a phenothiazine-based organic polymer hole transport material according to claim 1, wherein: In the process of "Under argon protection, potassium carbonate is dissolved in a small amount of distilled water, and intermediate II, intermediate III and tetrakis(triphenyl)phosphine palladium are sequentially added to toluene, stirred and dissolved, and the mixture is heated to 50°C for activation for 2 hours, then heated to 80°C and refluxed for 72 hours. The reaction is monitored by thin-layer chromatography until the concentration of the reactants remains constant, and then the reaction is stopped to obtain the polymer PPTZ-OM", the potassium carbonate is present in an amount of 4 molar parts; the intermediate II is present in an amount of 1 molar part; the intermediate III is present in an amount of 1 molar part; and the tetrakis(triphenyl)phosphine palladium is present in an amount of 0.01 molar part.

6. An application of a phenothiazine-based organic polymer hole transport material, using the preparation method of the phenothiazine-based organic polymer hole transport material according to any one of claims 1 to 5, characterized in that: Applied in the field of perovskite solar cells.

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