Preparation method and application of AIEgen type self-assembled hole transport materials

Abstract

The present invention discloses a preparation method and application of an AIEgen-type self-assembled hole transport material, having a structure represented by general formula (I) or general formula (II): wherein L1 and L2 are independently selected from a linear alkyl group of C2, C3, C4, C5, or C6; and R1, R2, R3, and R4 are independently selected from -H, -Br, -CF3, methyl, methoxy, hydroxyl, amino, phenyl, or carboxylic acid. This self-assembled hole transport material is used in perovskite solar devices to improve device efficiency and enhance stability; a dense and uniform hole transport layer is obtained, which effectively passivates defects, reduces non-radiative convergence, and improves device performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar device materials, and in particular relates to a preparation method and application of an AIEgen type self-assembled hole transport material. Background Art

[0002] Perovskite solar cells have become the most competitive technology in the next generation of photovoltaic technology due to their breakthroughs in efficiency, stability and cost-effectiveness. The structure of a formal perovskite solar device is, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer, and an electrode. In an inverse perovskite solar device, the positions of the electron transport layer and the hole transport layer are interchanged, while the rest of the structure remains unchanged. Inverse perovskite solar devices have become the focus of research by scientific researchers due to their simple preparation process, high stability, low-temperature preparation, and suitability for the preparation of stacked cells. Currently, commonly used hole transport materials include polymers such as PTAA, inorganic semiconductor materials such as NiOX, and organic small molecule materials such as self-assembled molecules (SAMs). Among them, SAMs are expected to become the hope for promoting the further development of perovskite solar devices due to their low cost, simple structure, adjustable energy levels, and easy modification.

[0003] Self-assembling molecules (SAMs) act as selective contact points in solar cells, determining the performance and stability of these photovoltaic devices. Current research on SAMs focuses primarily on improving efficiency and stability. However, devices fabricated using SAMs experience accelerated decomposition under UV light, hindering the long-term stability required for solar devices. They also suffer from shortcomings such as insufficient film uniformity and poor perovskite crystal growth. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of an AIEgen type self-assembled hole transport material, which is used in perovskite solar devices to improve device efficiency and enhance stability; a dense and uniform hole transport layer is obtained, which effectively passivates defects, reduces non-radiative convergence, improves device performance, and optimizes stability.

[0005] The present invention adopts the following technical solution: AIEgen type self-assembled hole transport material has a structure shown in general formula (I) or general formula (II):

[0006]

[0007] wherein L1 and L2 are independently selected from a C2, C3, C4, C5 or C6 straight chain alkyl group;

[0008] R1, R2, R3, and R4 are independently selected from -H, -Br, -CF3, methyl, methoxy, hydroxy, amino, phenyl, or carboxylic acid.

[0009] Furthermore, L1 and L2 independently select one of the following:

[0010]

[0011] The present invention also discloses a method for preparing the above-mentioned AIEgen type self-assembled hole transport material. The preparation process of the self-assembled hole transport material having the structure shown in general formula (I) is as follows:

[0012]

[0013] The preparation process of the self-assembled hole transport material having the structure shown in general formula (II) is as follows:

[0014]

[0015] The present invention also discloses the use of the above-mentioned AIEgen type self-assembled hole transport material, which is used to prepare an inverse perovskite solar device.

[0016] The present invention also discloses an inverse perovskite solar device based on the above-mentioned AIEgen type self-assembled hole transport material, which is used for the hole transport layer, which comprises, from bottom to top, a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer and an electrode.

[0017] The present invention has the following beneficial effects: 1. The preparation method is simple, achieving the reaction between borate and bromine without the need for water addition and subsequent complex post-processing. None of the synthesis steps require strict anhydrous and oxygen-free conditions to obtain the target molecule in high yield, resulting in high feasibility and potential for large-scale application. 2. By absorbing ultraviolet light, the damage to perovskite solar devices is reduced, further improving the stability and efficiency of perovskite solar devices and promoting the development of photovoltaic technology. 3. A dense hole transport layer is obtained during the device preparation process, which is conducive to achieving a uniform perovskite layer and high-quality film formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the H NMR spectrum of the compound of formula 9;

[0019] Figure 2 is the C NMR spectrum of the compound of formula 9;

[0020] Figure 3 is the H NMR spectrum of the compound of formula 25;

[0021] Figure 4 is the C NMR spectrum of the compound of formula 25;

[0022] Figure 5 The UV-visible diffuse reflectance spectra of the compounds of formula 9, 25, and 4PACz dissolved in ethanol;

[0023] Figure 6 is the JV curve of the perovskite solar device using the compound of formula 9;

[0024] Figure 7 is the JV curve of the perovskite solar device using the compound of formula 25;

[0025] Figure 8 25 under different volume fractions of THF / H2O. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The present invention provides an AIEgen type self-assembled hole transport material having a structure shown in general formula (I) or general formula (II):

[0028]

[0029]

[0030] wherein L1 and L2 are selected from C2, C3, C4, C5 or C6 linear alkyl groups;

[0031] R1, R2, R3, R4 are independently selected from -H, -Br, -CF3, methyl, methoxy, hydroxy, amino, phenyl or carboxylic acid;

[0032] The structure of phosphate is as follows:

[0033]

[0034] Wherein, “*” represents the connection position between the acid radical structure and the alkyl chain of general formula (I) or (II).

[0035] L1 and L2 independently select one of the following:

[0036]

[0037] The specific molecular structure of the self-assembled hole transport material is as follows:

[0038]

[0039]

[0040]

[0041] The invention also discloses the use of the self-assembled hole transport material in preparing an inverse perovskite solar device.

[0042] An inverse perovskite solar device, wherein the self-assembled hole transport material is used for the hole transport layer, and from bottom to top, it comprises a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer and an electrode.

[0043] Example 1

[0044] The synthesis process of self-assembly molecules of formula (1):

[0045]

[0046] Synthesis of compound of formula (1-2):

[0047] Under a nitrogen atmosphere, a dry round-bottom flask equipped with a magnetic stirrer was charged with the compound of formula (1-1) (1.00 g, 3.41 mmol, 1 eq), triphenylethylene bromide (1.14 g, 3.41 mmol, 1 eq.), Pd-P(t-Bu)3-G4 (111.2 mg, 0.17 mmol, 5.0 mol%), potassium trimethylsilanol (481.1 mg, 3.75 mmol, 1.1 eq.), and toluene (20 mL). The reaction mixture was then stirred at 45°C for 15 hours. The crude product was purified by column chromatography (PE:DCM 2:1 v:v) to give 1.21 g of white crystals in an 86% yield.

[0048] Synthesis of compound of formula (1-3):

[0049] The compound of formula (1-2) (1.00 g, 2.37 mmol, 1 eq) was dissolved in 1,4-dibromoethane (5 mL, 47.4 mmol, 20 eq), and tetrabutylammonium bromide (118.7 mg, 0.36 mmol, 0.15 eq) and 50% KOH aqueous solution (664.9 mg, 1.4 ml, 11.85 mmol, 5 eq) were added under a nitrogen atmosphere. The mixture was heated to 65 ° C and stirred overnight. After the reaction was completed, the reactant was extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (PE:DCM4:1 v:v) to give 890.1 mg of a white solid with a yield of 69.0%.

[0050] Synthesis of compound of formula (1-4):

[0051] Under a nitrogen atmosphere, 1-3 (800 mg, 1.51 mmol, 1 eq) was dissolved in triethyl phosphite (5.0 mL, 28.8 mmol, 20 eq) and stirred at 145° C. for 15 hours. After the reaction was complete, the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (DCM) to give 750.4 mg of an off-white solid with a yield of 89%.

[0052] Synthesis of compound of formula (1):

[0053] Under a nitrogen atmosphere, the compound of formula (1-4) (292.8 mg, 0.5 mmol, 1 eq) was dissolved in anhydrous 1,4-dioxane (6 mL), and bromotrimethylsilane (10 eq, 0.66 mL, 5 mmol) was added dropwise. The reaction was stirred at room temperature for 12 hours. The solvent was then partially distilled off under reduced pressure, and the liquid residue was dissolved in methanol (3 ml). Next, the liquid was poured into distilled water (30 ml). The product was then filtered and washed with water to obtain 150.6 mg of off-white solid with a yield of 56.9%.

[0054] Example 2

[0055] The synthesis process of self-assembly molecules of formula (17):

[0056]

[0057] Synthesis of compound of formula (17-2):

[0058] Under a nitrogen atmosphere, a dry round-bottom flask equipped with a stirring magnet was charged with formula (17-1) (1.00 g, 3.41 mmol, 1 eq), 1-(4-bromophenyl)-1,2,2-triphenylethylene (1.40 g, 3.41 mmol, 1 eq), Pd-P(t-Bu)3-G4 (111.2 mg, 0.17 mmol, 5.0 mol%), potassium trimethylsilanol (481.1 mg, 3.75 mmol, 1.1 eq.), and toluene (20 mL). The reaction mixture was then stirred at 45°C for 15 hours. The crude product was purified by column chromatography (PE:DCM 2:1 v:v) to give 1.53 g of white crystals with a yield of 84%.

[0059] Synthesis of compound of formula (17-3):

[0060] The compound of formula (17-2) (1.00 g, 2.01 mmol, 1 eq) was dissolved in 1,4-dibromoethane (5 mL, 47.4 mmol, 20 eq), and tetrabutylammonium bromide (97.2 mg, 0.30 mmol, 0.15 eq) and 50% KOH aqueous solution (563.9 mg, 1.13 ml, 10.05 mmol, 5 eq) were added under a nitrogen atmosphere. The mixture was heated to 65 ° C and stirred overnight. After the reaction was completed, the reactant was extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (PE:DCM 4:1 v:v) to give 896.3 mg of a white solid with a yield of 73.8%.

[0061] Synthesis of compound of formula (17-4):

[0062] Under a nitrogen atmosphere, compound (17-3) (800 mg, 1.32 mmol, 1 eq) was dissolved in triethyl phosphite (4.5 mL, 26.4 mmol, 20 eq) and stirred at 145° C. for 15 hours. After completion of the reaction, the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (DCM) to give 760.6 mg (87%) of an off-white solid.

[0063] Synthesis of compound of formula (17):

[0064] Under a nitrogen atmosphere, the compound of formula (17-4) (330.89 mg, 0.5 mmol, 1 eq) was dissolved in anhydrous 1,4-dioxane (6 mL), and bromotrimethylsilane (10 eq, 0.66 mL, 5 mmol) was added dropwise. The reaction was stirred at room temperature for 12 hours. The solvent was then partially distilled off under reduced pressure, and the liquid residue was dissolved in methanol (3 ml). Next, the liquid was poured into distilled water (30 ml). The product was then filtered and washed with water to obtain 162.1 mg of off-white solid with a yield of 53.5%.

[0065] Example 3

[0066] The synthesis process of self-assembly molecules in formula (9):

[0067]

[0068] Synthesis of compound of formula (9-2):

[0069] Under a nitrogen atmosphere, to a dry round-bottom flask equipped with a stirring magnet was added formula (9-1) (1.00 g, 3.41 mmol, 1 eq), triphenylethylene bromide (1.14 g, 3.41 mmol, 1 eq.), Pd-P(t-Bu)3-G4 (111.2 mg, 0.17 mmol, 5.0 mol%), potassium trimethylsilanol (481.1 mg, 3.75 mmol, 1.1 eq.) and toluene (20 mL), and the reaction mixture was stirred at 45°C for 15 hours. The crude product was purified by column chromatography (PE:DCM 2:1 v:v) to give 1.25 g of white crystals with a yield of 87%.

[0070] Synthesis of compound of formula (9-3):

[0071] The compound of formula (9-2) (1.00 g, 2.37 mmol, 1 eq) was dissolved in 1,4-dibromobutane (5.7 mL, 47.4 mmol, 20 eq), and tetrabutylammonium bromide (118.7 mg, 0.36 mmol, 0.15 eq) and 50% KOH aqueous solution (664.9 mg, 1.4 ml, 11.85 mmol, 5 eq) were added under a nitrogen atmosphere. The mixture was heated to 65 ° C and stirred overnight. After the reaction was completed, the reactant was extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (PE: DCM 4: 1 v: v) to give 976.1 mg of a white solid with a yield of 74.0%.

[0072] Synthesis of compound of formula (9-4):

[0073] Under nitrogen atmosphere, 9-3 (800 mg, 1.44 mmol, 1 eq) was dissolved in triethyl phosphite (5.0 mL, 28.8 mmol, 20 eq) and stirred at 145° C. for 15 hours. After the reaction was complete, the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (DCM) to give 795.8 mg (92%) of an off-white solid.

[0074] Synthesis of self-assembling molecules of formula (9):

[0075] Under a nitrogen atmosphere, compound 9-4 (306.9 mg, 0.5 mmol, 1 eq) was dissolved in anhydrous 1,4-dioxane (6 mL), and bromotrimethylsilane (10 eq, 0.66 mL, 5 mmol) was added dropwise. The reaction was stirred at room temperature for 12 hours. The solvent was then partially distilled off under reduced pressure, and the liquid residue was dissolved in methanol (3 ml). Next, the liquid was poured into distilled water (30 ml). The product was then filtered and washed with water to obtain 164.5 mg of off-white solid with a yield of 59%. Figure 1As shown, the measured self-assembly molecules of formula 9 1 The H NMR spectrum was integrated and analyzed to obtain 1H NMR (600 MHz, DMSO) δ7.85 (d, J = 7.3 Hz, 1H), 7.71 (s, 1H), 7.56 (d, J = 7.8 Hz, 1H), 7.40-7.37 (m, 1H), 7.13-7.00 (m, 9H), 4.30 (s, 2H), 1.79 (s, 1H), 1.53 (s, 3H). 13C NMR (151MHz, DMSO) δ 131.27 (d, J = 9.7 Hz, 1H), 128.25 (d, J = 3.9 Hz, 1H), 40.41 (s, 6H), 40. 27(s,22H),40.13(s,22H),39.99(s,32H),39.85(s,25H),39.71(s,19H),39.57(s,5H). Figure 2 The 13C NMR spectrum of the self-assembled molecule of formula 9 was measured and integrated, and the obtained 13C NMR (151 MHz, DMSO) δ was 131.27 (d, J = 9.7 Hz, 1H), 128.25 (d, J = 3.9 Hz, 1H), 40.41 (s, 6H), 40.27 (s, 22H), 40.13 (s, 22H), 39.99 (s, 32H), 39.85 (s, 25H), 39.71 (s, 19H), 39.57 (s, 5H). In summary, the self-assembled molecule of formula (9) was prepared by the above method.

[0076] Example 4

[0077] The synthesis process of self-assembly molecules of formula (25):

[0078]

[0079] Synthesis of compound of formula (25-2):

[0080] Under a nitrogen atmosphere, a dry round-bottom flask equipped with a stirring magnet was charged with formula (25-1) (1.00 g, 3.41 mmol, 1 eq), 1-(4-bromophenyl)-1,2,2-triphenylethylene (1.40 g, 3.41 mmol, 1 eq), Pd-P(t-Bu)3-G4 (111.2 mg, 0.17 mmol, 5.0 mol%), potassium trimethylsilanol (481.1 mg, 3.75 mmol, 1.1 eq.), and toluene (20 mL). The reaction mixture was then stirred at 45°C for 15 hours. The crude product was purified by column chromatography (PE:DCM 2:1 v:v) to give 1.41 g of white crystals with a yield of 83%.

[0081] Synthesis of compound of formula (25-3):

[0082] The compound of formula (25-2) (1.00 g, 2.01 mmol, 1 eq) was dissolved in 1,4-dibromobutane (4.8 mL, 40.2 mmol, 20 eq), and tetrabutylammonium bromide (97.2 mg, 0.30 mmol, 0.15 eq) and 50% KOH aqueous solution (563.9 mg, 1.13 ml, 10.05 mmol, 5 eq) were added under a nitrogen atmosphere. The mixture was heated to 65 ° C and stirred overnight. After the reaction was completed, the reactant was extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (PE:DCM 4:1 v:v) to give 919.4 mg of a white solid with a yield of 72.3%.

[0083] Synthesis of compound of formula (25-4):

[0084] Under nitrogen atmosphere, 25-3 (800 mg, 1.26 mmol, 1 eq) was dissolved in triethyl phosphite (4.34 mL, 25.3 mmol, 20 eq) and stirred at 145° C. for 15 hours. After the reaction was complete, the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (DCM) to give 782.3 mg of an off-white solid with a yield of 90%.

[0085] Synthesis of self-assembling molecules of formula (25):

[0086] Under a nitrogen atmosphere, compound 25-4 (344.9 mg, 0.5 mmol, 1 eq) was dissolved in anhydrous 1,4-dioxane (6 mL), and bromotrimethylsilane (10 eq, 0.66 mL, 5 mmol) was added dropwise. The reaction was stirred at room temperature for 12 hours. The solvent was then partially distilled off under reduced pressure, and the liquid residue was dissolved in methanol (3 ml). Next, the liquid was poured into distilled water (30 ml). The product was then filtered and washed with water to obtain 177.4 mg (56%) of off-white solid.

[0087] The self-assembled molecules of formula 25 prepared in Example 4 were measured using a Bruker AVANCE III HD600 MHz spectrometer using DMSO-d6 as solvent. 1 H NMR spectra and 13 C NMR spectrum.

[0088] Figure 3 is the measured self-assembly molecule of formula 25 1H NMR spectrum, which was analyzed, obtained 1H NMR (600 MHz, DMSO) δ8.44 (d, J = 1.5 Hz, 1H), 8.22 (d, J = 7.7 Hz, 1H), 7.71 (dd, J = 8.6, 1.7 Hz, 1H), 7.66–7.56 (m, 5H), 7.45 (t, J = 7.6 Hz, 1H), 7.21–7.16 (m, 5H), 7.16–7.12 (m, 5H), 7.07–7.03 (m, 5H), 7.00–6.98 (m, 2H), 4.40 (t, J = 7.0 Hz, 2H), 3.57 (s, 2H), 1.88–1.83 (m, 2H), 1.55–1.51 (m, 4H); Figure 4 is the measured self-assembly molecule of formula 25 13 The C NMR spectrum was integrated and analyzed to obtain 13C NMR (151 MHz, DMSO) δ131.19 (d, J = 11.0 Hz, 1H), 128.70–128.21 (m, 1H), 40.41 (s, 6H), 40.20 (d, J = 21.0 Hz, 29H), 40.01 (s, 18H), 39.99 (s, 37H), 39.85 (s, 19H), 39.71 (s, 14H), 39.57 (s, 4H). The self-assembling molecule of formula 25 was synthesized using the above method.

[0089] Optical performance test:

[0090] The UV-visible absorption spectra of the self-assembling molecules of formula 9 and 25 prepared in Example 3 and Example 4 and the commonly used self-assembling molecule 4PACz in solution were measured using a UV-visible spectrophotometer, and the optical band gap was calculated using the empirical formula Eg = 1240 / λ absorption margin. 10-5 mol / L solutions of the self-assembling molecules of formula 9, 25 and 4PACz dissolved in ethanol were prepared and analyzed using a UV-visible spectrophotometer. The results were as follows: Figure 5 The UV-visible absorption spectra are shown in Table 1, and the optical performance parameters of the self-assembled molecules of Formulas 9 and 25 are obtained. Figure 5 As shown in Table 1, the self-assembled molecule of Formula 25 has the largest peak, followed by the self-assembled molecule of Formula 9 and 4PACz. The conventional self-assembled molecule 4PACz has the weakest UV absorption. Therefore, it can be seen that the introduction of molecules with AIE properties enhances the UV absorption of the hole transport layer. It can be inferred that the self-assembled molecule of Formula 25 can effectively prevent UV damage to perovskite solar cells, and the UV absorption of AIEgen-type self-assembled molecules is stronger than that of the conventional self-assembled molecule 4PACz.

[0091] Table 1 Optical performance parameter test results

[0092] Self-assembling molecules band gap Formula 9 3.84eV Formula 25 3.86eV

[0093] Device performance test:

[0094] The self-assembled hole transport materials of formula 9 and formula 25 were used to prepare perovskite solar devices and tested, such as Figure 6 and Figure 7 As shown in the figure, during the preparation of perovskite solar devices, a dense hole transport layer and a uniform perovskite layer with high film quality were observed. Figure 6 and Figure 7 The JV curves of Equations 9 and 25, respectively, when used as hole transport layers in perovskite solar devices, show that both achieve high open-circuit voltages (1.81 V for Equation 9 and 1.83 for Equation 25). Therefore, the prepared self-assembled molecules with AIE properties can serve as efficient hole transport layers for use in perovskite solar devices.

[0095] AIE performance test:

[0096] The photoluminescence (PL) behavior of the self-assembled molecules of formula 25 prepared in Example 4 in tetrahydrofuran / water with different volume fractions was studied by steady-state fluorescence measurement. Figure 8 It can be seen that when tetrahydrofuran is not added, the self-assembled molecules of Formula 25 exhibit almost no fluorescence in aqueous solution. However, as the content of the poor solvent tetrahydrofuran increases from 0% to 90%, aggregates form, and the luminescence of the entire system increases. The results show that the self-assembled molecules of Formula 25, as well as AIEgen-type self-assembled hole transport materials with structures represented by general formula (I) or general formula (II), exhibit AIE properties. Self-assembled molecules with AIE properties have stronger absorption of ultraviolet light, which is beneficial for the long-term stability of perovskite solar devices. They can also convert absorbed ultraviolet light into visible light, improving the utilization rate of sunlight.

Claims

1. AIEgen type self-assembled hole transport material, characterized in that Having the structure shown by general formula (I) or general formula (II): wherein L1 and L2 are independently selected from a C2, C3, C4, C5 or C6 straight chain alkyl group; R1, R2, R3, and R4 are independently selected from -H, -Br, -CF3, methyl, methoxy, hydroxy, amino, phenyl, or carboxylic acid.

2. The AIEgen type self-assembled hole transport material according to claim 1, characterized in that L1 and L2 independently select one of the following:

3. The method for preparing the AIEgen type self-assembled hole transport material according to claim 1 or 2, wherein: The preparation process of the self-assembled hole transport material having the structure shown in the general formula (I) is as follows: The preparation process of the self-assembled hole transport material having the structure shown in the general formula (II) is as follows: Among them: n = 2, 3, 4, 5, 6.

4. Use of the AIEgen type self-assembled hole transport material according to claim 1 or 2, characterized in that: It is used to prepare inverse perovskite solar devices.

5. An inverse perovskite solar device based on the AIEgen self-assembled hole transport material according to claim 1 or 2, characterized in that: It is used for the hole transport layer, which consists of a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer and an electrode from bottom to top.

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