A pyridinium salt self-assembly material, inverse perovskite solar cell and its application

Abstract

The present application relates to the technical field of perovskite solar cells, and discloses a pyridinium salt self-assembly material, an inverse perovskite solar cell and its application. The chemical structure of the pyridinium salt self-assembly material is shown in formula (1): wherein R1, R2 and R3 are each independently hydrogen or an aromatic amine group. The inverse perovskite solar cell of the present application comprises ITO, a hole transport layer, a perovskite active layer, an electron transport layer, and a metal electrode, and the hole transport layer is prepared from the above-mentioned pyridinium salt self-assembly material. The pyridinium salt self-assembly material of the present application is low in price and has good wettability. As a hole transport layer, it is conducive to the spreading of the perovskite layer, and the perovskite film can be prepared without interface rinsing or spin coating of the interface material, which simplifies the preparation process of the perovskite cell and reduces its production cost. The perovskite solar cell containing the hole transport layer (3PA‑TPPyA) can achieve 25.06mA / cm 2 The short-circuit current, open-circuit voltage of 1.85V and photoelectric conversion efficiency can reach 23.54%.

Description

Technical Field

[0001] The present application relates to the technical field of perovskite solar cells, and in particular to a pyridinium salt self-assembly material, an inverse perovskite solar cell and applications thereof. Background Art

[0002] Inverse perovskite solar cells (PSCs) have long been favored by researchers due to their low-temperature processability, low material consumption, and compatibility with a variety of substrates. However, they suffer from high energy losses, resulting in low device efficiency. To reduce recombination losses at the interface between the perovskite and the hole-selective layer, self-assembled organic materials (SAMs) have been introduced as hole-selective layers in inverse PSCs. These materials effectively reduce interfacial recombination losses and improve the efficiency of inverse PSCs, consistently breaking efficiency records for inverse PSCs in recent years.

[0003] Currently, SAMs are mainly carbazole derivatives, which are expensive, resulting in excessively high device preparation costs and, in turn, high commercialization costs. In addition, carbazole SAMs have poor wettability, and during the preparation process, interface rinsing or spin coating of interface materials are required to improve their wettability for perovskite spreading, which increases the complexity of the process and is not conducive to large-scale production.

[0004] To further optimize the wettability of self-assembled monolayers, additives are often added to the self-assembling materials to form co-self-assembled layers. These additives typically contain long alkyl chains with an anchoring group at one end and an ammonium salt at the other. This strategy not only improves the wettability of the self-assembled monolayer but also allows the additives to interact with the perovskite, resulting in the production of better perovskite films. However, the addition of additives to the self-assembling materials increases the complexity of the process and the cost of production.

[0005] Based on this, new self-assembly materials need to be developed. Summary of the Invention

[0006] The present application provides a pyridinium salt self-assembly material, an inverse perovskite solar cell and its application, aiming to solve the problem that the existing self-assembly materials used for hole transport layers are expensive and have poor wettability, resulting in a complex perovskite cell preparation process and high production cost.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions.

[0008] In a first aspect of the present application, a pyridinium salt self-assembly material is provided, the chemical structure of which is shown in formula (1):

[0009]

[0010] Wherein, R1, R2 and R3 are each independently hydrogen or an aromatic amine group.

[0011] In some embodiments:

[0012] The aromatic amine group is a carbazole group or Wherein, R4 and R5 are each independently selected from a C1-C10 alkoxy group.

[0013] In some embodiments:

[0014] The aromatic amine group is

[0015] In some embodiments, R1, R2, and R3 are all hydrogen, and their structure is shown in Formula (1-1):

[0016]

[0017] In some embodiments, at least one of R1, R2 and R3 is

[0018] In some embodiments, R1 and R3 are hydrogen, R2 is

[0019] Its structure is shown in formula (1-2):

[0020]

[0021] In some embodiments, R2 is hydrogen, R1 and R3 are

[0022] Its structure is shown in formula (1-3):

[0023]

[0024] The second aspect of the present application provides the application of the above-mentioned pyridinium salt self-assembly material in perovskite solar cells.

[0025] The third aspect of the present application provides an inverted perovskite solar cell, comprising ITO, a hole transport layer, a perovskite active layer, an electron transport layer, and a metal electrode, wherein the hole transport layer is prepared from the above-mentioned pyridinium salt self-assembly material.

[0026] In a fourth aspect of the present application, a method for preparing the above-mentioned inverse perovskite solar cell is provided, comprising:

[0027] A layer of self-assembled material is spin-coated on indium tin oxide conductive glass as a hole transport layer;

[0028] Spin coating a layer of perovskite precursor solution on the hole transport layer as a perovskite layer;

[0029] C is evaporated on the perovskite layer 60and BCP as electron transport layer;

[0030] The electron transport layer is evaporated onto metallic silver as an electrode.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] The pyridinium salt self-assembly material of the present application can be used to prepare a hole transport layer. It has a pyridinium salt as the core and phosphate as the anchoring group. The phosphate group interacts with ITO to fill oxygen vacancies, and the dipole moment is used to adjust the work function of ITO and improve the open-circuit voltage of the device. The positively charged nitrogen atoms in the zwitterions interact with the Pb-I antisite defects to passivate the defects, and the bromide ions can fill the anion vacancies in the perovskite. The pyridinium salt acts as an electron-withdrawing group, which can enhance the anchoring ability of phosphate on ITO.

[0033] The pyridinium salt self-assembly material of the present application is low in price and has good wettability. It is conducive to the spreading of the perovskite layer as a hole transport layer. The perovskite film can be prepared without interface rinsing or spin coating of interface materials, which simplifies the preparation process of perovskite cells and reduces their production costs. The inverse perovskite solar cell containing this hole transport layer (3PA-TPPyA) can achieve 25.06mA / cm 2 The short-circuit current, open-circuit voltage of 1.185V and photoelectric conversion efficiency can reach 23.54%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some of the embodiments described in this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0035] Figure 1 The UV-visible absorption spectrum (UV) of the self-assembled hole transport material prepared in this application;

[0036] Figure 2 Cyclic voltammetry (CV) diagram of the self-assembled hole transport material prepared in this application;

[0037] Figure 3 Thermogravimetric (TGA) test results of the self-assembled hole transport material prepared in this application;

[0038] Figure 4 The water contact angle test graph of the self-assembled hole transport material prepared in this application, i.e., the existing commercial self-assembled hole transport material;

[0039] Figure 5The current-voltage (JV) curves of the inverse perovskite solar cells prepared in the examples and comparative examples of this application are shown. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0041] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are open-ended terms, meaning including but not limited to.

[0042] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0043] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0044] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0045] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0046] It will be understood by those skilled in the art that the numerical ranges in the examples of the present application are to be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also included in the present application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0047] Unless otherwise indicated, the technical / scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. Although this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

[0048] In a first aspect, the present application provides a pyridinium salt self-assembly material, the chemical structure of which is shown in formula (1):

[0049]

[0050] Wherein, R1, R2 and R3 are each independently hydrogen or aromatic amine.

[0051] In the present application, it is preferred that the aromatic amine group is a carbazole group or Wherein, R4 and R5 are each independently selected from a C1-C10 alkoxy group; more preferably, R4 and R5 are both methoxy groups, and the aromatic amine group is:

[0052]

[0053] In the present application, in the structural formula of the pyridinium salt self-assembly material, preferably R1, R2 and R3 are all hydrogen, and its structure is shown in formula (1-1). The pyridinium salt self-assembly material is recorded as 3PAPy.

[0054]

[0055] Its synthetic reaction formula is:

[0056]

[0057] In the present application, in the structural formula of the pyridinium salt self-assembly material, at least one of R1, R2 and R3 is preferably For example, R1 and R3 are hydrogen, R2 is Its structure is shown in formula (1-2), and the pyridinium salt self-assembly material is recorded as 3PA-DPPyA.

[0058]

[0059] Its synthetic reaction formula is:

[0060]

[0061] Alternatively, R2 is hydrogen, R1 and R3 are Its structure is shown in formula (1-3), and the pyridinium salt self-assembly material is recorded as 3PA-TPPyA.

[0062]

[0063] Its synthetic reaction formula is:

[0064]

[0065] The preparation method of 3PA-TPPyA comprises:

[0066] S1, dissolving 3,5-dibromopyridine and 4,4'-dimethoxydiphenylamine in anhydrous toluene, and reflux in the presence of sodium tert-butoxide, 1,1'-bis(diphenylphosphino)ferrocene, and tris(dibenzylideneacetone)dipalladium to obtain compound I;

[0067] S2, compound I is mixed with 3-bromopropyl diethyl phosphate and ultra-dry acetonitrile and refluxed to obtain compound II;

[0068] S3, compound II is mixed with trimethylsilyl bromide and chloroform at room temperature to obtain the product.

[0069] Secondly, the pyridinium salt self-assembly material of the present application is low-priced, has a simple preparation process, and has good wettability, which is conducive to the spreading of the perovskite layer. It can be used as a hole transport layer material in inverse perovskite solar cells.

[0070] In a third aspect, the present application provides an inverted perovskite solar cell comprising ITO, a hole transport layer, a perovskite active layer, an electron transport layer, and a metal electrode, wherein the hole transport layer is prepared from the above-mentioned pyridinium salt self-assembled material. The pyridinium salt self-assembled material of the present application has a pyridinium salt as a core and phosphate as an anchoring group. The phosphate group interacts with the ITO to fill oxygen vacancies, while the dipole moment is used to adjust the work function of the ITO and improve the open-circuit voltage of the perovskite solar cell. The positively charged nitrogen atoms in the zwitterions interact with the Pb-I antisite defects, passivating the defects, and the bromide ions can fill the anion vacancies in the perovskite. The pyridinium salt acts as an electron-withdrawing group, which can enhance the anchoring ability of the phosphate on the ITO.

[0071] In a fourth aspect, the present application provides a method for preparing the above-mentioned inverse perovskite solar cell, comprising:

[0072] A layer of self-assembled material is spin-coated on indium tin oxide conductive glass as a hole transport layer;

[0073] Spin coating a layer of perovskite precursor solution on the hole transport layer as a perovskite layer;

[0074] C is evaporated on the perovskite layer 60 and BCP as electron transport layer; among them, C 60 The thickness of is preferably 20 nm, and the thickness of BCP is preferably 7 nm.

[0075] The electron transport layer is evaporated onto metallic silver as an electrode.

[0076] The present application is further described below through examples.

[0077] Example 1

[0078] This embodiment provides a method for preparing a pyridinium salt self-assembly material 3PA-TPPyA, comprising:

[0079] Step 1: 2 mmol of 3,5-dibromopyridine, 4 mmol of 4,4'-dimethoxydiphenylamine, 15 mmol of sodium tert-butoxide, and 0.06 mmol of 1,1'-bis(diphenylphosphino)ferrocene were added sequentially to a two-necked flask. A magnetic stirrer was added and the mixture was evacuated under a Schlenk tube. Then, under a nitrogen atmosphere, 0.3 mmol of tris(dibenzylideneacetone)dipalladium and 50 mL of anhydrous toluene were added. The mixture was refluxed at 110°C for 12 hours. After cooling to room temperature, the mixture was washed with water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography using a dichloromethane:n-hexane ratio of 2:1 as the eluent to obtain 1.8 mmol of Compound I as a pale yellow solid in a 90% yield. The reaction equation for Step 1 is:

[0080]

[0081] Compound I was characterized by nuclear magnetic resonance, and the results were as follows:

[0082] 1 H NMR (400MHz, CDCl3) δ7.69 (s, 2H), 7.00 (d, J = 8.9 Hz, 8H), 6.79 (d, J = 8.9 Hz, 9H), 3.77 (s, 12H).

[0083] Step 2: 1.8 mmol of Compound I, 2.7 mmol of 3-bromopropyl diethyl phosphate, and a magnetic stirring bar were added to a two-necked flask. The mixture was pumped three times under a Schlenk tube. 10 ml of anhydrous acetonitrile was added under nitrogen, and the mixture was refluxed at 80°C for 12 hours. After cooling to room temperature, the solution was evaporated to a small amount on a rotary evaporator under reduced pressure. The concentrated solution was settled in diethyl ether. After the suspension settled and became clear, the supernatant was poured out. The oily liquid on the wall of the flask was dissolved with a small amount of chloroform and then continued to settle with anhydrous diethyl ether to completely remove excess 3-bromopropyl diethyl phosphate. 1.7 mmol of Compound II was obtained as a yellow oily liquid with a yield of 95%. The reaction formula for Step 2 is:

[0084]

[0085] Compound II was characterized by nuclear magnetic resonance, and the results were as follows:

[0086] 1 H NMR (400MHz, DMSO) δ7.60(d,J=2.2Hz,2H),7.17(d,J=9.0Hz,8H),6.95(d,J=9.0Hz,8H),6.58(s,1H),4.29(t,J =7.2Hz,2H),4.01–3.94(m,4H),3.74(s,12H),1.86(d,J=6.2Hz,2H),1.75–1.64(m,2H),1.22(t,J=7.0Hz,6H).

[0087] Step 3: Add 1.7 mmol of compound II, 25.5 mmol of bromotrimethylsilane, and a magnetic stirrer to a two-necked flask. Pump three times under a Schlenk tube. Add 20 ml of chloroform under nitrogen, and reflux at 80°C for 12 hours. After cooling to room temperature, add 50 ml of methanol and continue stirring for 12 hours. After the reaction is quenched, evaporate to a small amount of solution on a rotary evaporator under reduced pressure. The concentrate is settled in diethyl ether. After the suspension settles and becomes clear, pour off the supernatant, dissolve the oily liquid on the wall of the flask with a small amount of chloroform, and continue settling with anhydrous diethyl ether to completely remove impurities. This yields 1.55 mmol of compound 3PA-TPPyA as a yellow oily liquid in a 91.2% yield. The reaction equation for Step 3 is:

[0088]

[0089] The compound 3PA-TPPyA was characterized by nuclear magnetic resonance, and the results were:

[0090] 1H NMR (600MHz, DMSO) δ7.62(s,2H),7.17(d,J=9.0Hz,8H),6.95(d,J=9.1Hz,8H),6.57(t,J= 2.1Hz,1H),4.30(t,J=7.3Hz,2H),3.74(s,12H),1.85(t,J=9.2Hz,2H),1.49-1.42(m,2H). 13 C NMR (151MHz, DMSO) δ157.95,148.39,137.07,128.10,123.05,115.94,113.86,55.84,26.10,24.88,23.97.

[0091] Example 2

[0092] This embodiment provides a method for preparing a pyridinium salt self-assembly material 3PA-DPPyA, comprising:

[0093] Step 1: 3 mmol of 4-bromopyridine, 3 mmol of 4,4'-dimethoxydiphenylamine, 15 mmol of sodium tert-butoxide, and 0.09 mmol of 1,1'-bis(diphenylphosphino)ferrocene were sequentially added to a two-necked flask. A magnetic stirrer was added and the mixture was evacuated under a Schlenk tube. Then, under a nitrogen atmosphere, 0.06 mmol of tris(dibenzylideneacetone)dipalladium and 50 ml of anhydrous toluene were added. The mixture was refluxed at 110°C for 12 hours. After cooling to room temperature, the mixture was washed with water and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography using a 1:1 ratio of dichloromethane to n-hexane as the eluent to afford 2.8 mmol of Compound I as a pale yellow solid in a 93% yield. The reaction equation for Step 1 is:

[0094]

[0095] Compound I was characterized by nuclear magnetic resonance, and the results were as follows:

[0096] 1 H NMR (600MHz, DMSO) δ 8.10 (d, J = 6.6 Hz, 2H), 7.22 (d, J = 8.9 Hz, 4H), 7.00 (d, J = 8.9 Hz, 4H), 6.42 (d, J = 6.5 Hz, 2H), 3.77 (s, 6H).

[0097] Step 2: Add 2.8 mmol of Compound I, 4.2 mmol of 3-bromopropyl diethyl phosphate, and a magnetic stirring rod to a two-necked flask. Pump three times under a Schlenk tube. Add 15 ml of anhydrous acetonitrile under nitrogen, and reflux at 80°C for 12 hours. After cooling to room temperature, evaporate to a small amount of solution on a rotary evaporator under reduced pressure. The concentrate is settled in diethyl ether. After the suspension settles and becomes clear, pour out the supernatant, dissolve the oily liquid on the wall of the flask with a small amount of chloroform, and continue settling with anhydrous diethyl ether to completely remove excess 3-bromopropyl diethyl phosphate. Finally, 1.71 mmol of Compound II is obtained as a yellow oily liquid with a yield of 90%. The reaction formula for Step 2 is:

[0098]

[0099] Compound II was characterized by nuclear magnetic resonance, and the results were as follows:

[0100] 1 H NMR (400MHz, DMSO) δ8.32(d,J=7.7Hz,2H),7.44(d,J=8.9Hz,4H),7.10(d,J=9.0Hz,4H),6.71(s,2H),4.27(t ,J=7.1Hz,2H),4.04–3.94(m,4H),3.80(s,6H),2.01–1.89(m,2H),1.80–1.69(m,2H),1.23(t,J=7.0Hz,6H).

[0101] Step 3: Add 1.71 mmol of compound II, 25.65 mmol of bromotrimethylsilane, and a magnetic stirring rod to a two-necked flask. Pump three times under a Schlenk tube. Add 20 ml of chloroform under nitrogen, and reflux at 80°C for 12 hours. After cooling to room temperature, add 50 ml of methanol and continue stirring for 12 hours. After the reaction is quenched, evaporate to a small amount of solution on a rotary evaporator under reduced pressure. The concentrated solution is settled in diethyl ether. After the suspension settles and becomes clear, pour off the supernatant, dissolve the oily liquid on the wall of the flask with a small amount of chloroform, and continue settling with anhydrous diethyl ether to completely remove impurities. The final yellow oily liquid compound 3PA-DPPyA (1.59 mmol) is obtained in a 93% yield. The reaction formula for Step 3 is:

[0102]

[0103] The compound 3PA-DPPyA was characterized by nuclear magnetic resonance, and the results were:

[0104] 1H NMR (400MHz, DMSO) δ8.31(d,J=7.7Hz,2H),7.45(d,J=8.9Hz,4H),7.10(d,J=8.9Hz,4H),6.7 1(d,J=7.7Hz,2H),4.28(t,J=7.0Hz,2H),3.79(s,6H),2.00–1.89(m,2H),1.54–1.43(m,2H). 13 C NMR (101MHz, DMSO) δ158.85,157.79,145.60,136.33,128.95,117.29,111.49,55.18,25.96,25.26,23.79.

[0105] Example 3

[0106] This embodiment provides a method for preparing a pyridinium salt self-assembly material 3PAyA, comprising:

[0107] Step 1: 1 mmol of pyridine, 1.5 mmol of 3-bromopropyl diethyl phosphate, and a magnetic stirring bar were added to a two-necked flask. The mixture was pumped three times under a Schlenk tube. 5 ml of anhydrous acetonitrile was added under nitrogen, and the mixture was refluxed at 80°C for 12 hours. After cooling to room temperature, the solution was evaporated to a small amount on a rotary evaporator under reduced pressure. The concentrate was settled in diethyl ether. After the suspension settled and became clear, the supernatant was poured out. The oily liquid on the wall of the flask was dissolved with a small amount of chloroform and then continued to settle with anhydrous diethyl ether to completely remove excess 3-bromopropyl diethyl phosphate. 0.83 mmol of Compound I was obtained as a yellow oily liquid with a yield of 83%. The reaction formula for Step 1 is:

[0108]

[0109] Compound I was characterized by nuclear magnetic resonance, and the results were as follows:

[0110] 1 H NMR (600MHz, DMSO) δ9.13(d,J=6.7Hz,2H),8.63(t,J=7.8Hz,1H),8.35(t,J=1.2Hz,1H),8.18(t,J=7.0Hz,2H),4.6 8(t,J=7.4Hz,2H),3.99(dqd,J=10.3,6.9,3.5Hz,4H),2.18–2.08(m,2H),1.85–1.76(m,2H),1.23(t,J=7.0Hz,6H).

[0111] Step 2: 0.5 mmol of compound I, 7.5 mmol of bromotrimethylsilane, and a magnetic stirring bar were added to a two-necked flask. The mixture was pumped three times under a Schlenk tube. 20 ml of chloroform was added under nitrogen, and the mixture was refluxed at 80°C for 12 hours. After cooling to room temperature, 10 ml of methanol was added and stirring continued for 12 hours. After the reaction was quenched, the solution was evaporated to a small amount on a rotary evaporator under reduced pressure. The concentrated solution was settled in diethyl ether. After the suspension settled and became clear, the supernatant was poured out. The oily liquid on the wall of the flask was dissolved with a small amount of chloroform and then continued to settle with anhydrous diethyl ether to completely remove impurities. 0.44 mmol of compound 3PAPy was obtained as a yellow oily liquid with a yield of 88%. The reaction formula for Step 2 is:

[0112]

[0113] The compound 3PAPy was characterized by nuclear magnetic resonance, and the results were:

[0114] 1 H NMR (400MHz, DMSO) δ9.14 (d, J = 6.2 Hz, 2H), 8.64 (t, J = 7.8 Hz, 1H), 8.19 (t, J = 7. 1Hz, 2H), 4.70 (t, J = 7.2Hz, 2H), 2.13 (q, J = 9.7, 7.9Hz, 2H), 1.65–1.43 (m, 2H).

[0115] Comparative Example 1

[0116] The comparative example is the existing carbazole derivative self-assembly material (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz).

[0117] The performance evaluation of the self-assembly material 3PA-TPPyA prepared in Example 1, the self-assembly material 3PA-DPPyA prepared in Example 2, and the self-assembly material 3PAPy prepared in Example 3 of the present application was performed, including:

[0118] 1. Ultraviolet-visible absorption spectrum test, the test instrument is Hitachi's U-3310, the results are as follows Figure 1 As shown. Figure 1 The main absorption peaks of 3PA-TPPyA and 3PA-DPPyA are at 250-270 nm, which is caused by π-π* electron transitions. The absorption peak of 3PA-TPPyA between 370 and 500 nm is caused by intramolecular charge transfer between the diarylamine and pyridine. The main absorption peak of 3PAPy is at 250-270 nm.

[0119] 2. Cyclic voltammetry test, the test instrument is CHI660A, the results are as follows Figure 2 As shown. Figure 2 The cyclic voltammograms calculated showed that the HOMO levels of 3PA-DPPyA, 3PA-TPPyA, and 3PAPy were -5.50 eV, -5.68 eV, and -5.19 eV, respectively.

[0120] 3. Thermogravimetric (TGA) test, the test instrument is PE company's Diamond TG / DTA, the results are as follows Figure 3 As shown. Figure 3 It can be seen that the thermal decomposition temperatures (Td) of 3PA-DPPyA and 3PA-TPPyA are both 283.2°C, and the thermal decomposition temperature of 3PAPy is 249.4°C; the thermal decomposition temperatures of the above three self-assembled materials are much higher than the annealing temperature, ensuring that the self-assembled materials will not decompose during the annealing process, thereby not affecting the performance of the device.

[0121] The wettability test was conducted on the self-assembly materials 3PA-TPPyA, 3PA-DPPyA, 3PAPy prepared in Examples 1-3 and 2PACz in Comparative Example 1. The results are shown in FIG. Figure 4 As shown, (a) is the water contact angle test picture of 2PACz, (b) is the water contact angle test picture of 3PA-DPPyA, (c) is the water contact angle test picture of 3PA-TPPyA, and (d) is the water contact angle test picture of 3PAPy. Figure 4 It can be seen that the water contact angles of 2PACz, 3PA-DPPyA, 3PA-TPPyA, and 3PAPy are 89.9°, 39.3°, 28.6°, and 27.3°, respectively. The water contact angles of the self-assembled materials prepared in Examples 1-3 are much smaller than those of the self-assembled materials in the comparative example, and they have excellent wettability. Their more hydrophilic surfaces are conducive to complete coverage of the perovskite precursor.

[0122] The self-assembled materials of Examples 1-3 and the comparative example were respectively used to prepare an inverse perovskite solar cell, wherein the inverse perovskite solar cell is composed of ITO, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode, wherein the hole transport layer is prepared from the self-assembled material.

[0123] Example 4

[0124] This embodiment provides a method for preparing a perovskite solar cell, wherein the hole transport layer is prepared from 3PA-TPPyA, comprising the following steps:

[0125] Step 1: Clean the ITO substrate with ultrasound, then clean it with acetone, deionized water, and isopropyl alcohol in sequence, each cleaning for 15 minutes, and then dry it with high-purity nitrogen; finally, clean it in a UV ozone cleaner for 20 minutes.

[0126] Step 2: Dissolve the self-assembly material 3PA-TPPyA in IPA at a concentration of 1.5 mg / mL and shake for two hours to completely dissolve it. Then, drop 50 microliters of the self-assembly material solution on the ITO and spin coat it on a spin coater at a speed of 3500 rpm / s. Then anneal it at 100°C for 10 minutes to form a hole transport layer.

[0127] Step 3, follow Cs 0.05 FA 0.85 MA 0.1 The perovskite precursor was prepared with a ratio of PbI3, and the solvent was DMF:DMSO = 4:1. 60 microliters of the perovskite precursor solution was dropped onto the hole transport layer, and the spin was first performed at 1000 rpm / s for 10 seconds, then increased to 4000 rpm / s for 30 seconds. 170 microliters of chlorobenzene was injected 10 seconds before the end of the program. The perovskite was then placed on a hot plate and annealed at 100°C for 30 minutes. After annealing, 50 microliters of 1.3 mg / mL F-PEAI solution was spin-coated on the perovskite layer at 3000 rpm / s, and then annealed at 100°C for 10 minutes. 20 nm of C was then evaporated in an evaporator. 60 and 7nm BCP and 80nm silver electrode.

[0128] The structure of the prepared perovskite solar cell is: ITO / HTL / perovskite / ETL / Ag, and its cathode area is defined as the effective active area of ​​the device, which is 0.04 cm 2 In this embodiment, a surface profilometer was used to measure the thickness of each spin-coated layer, and a thickness / speed meter (Model STM-100) produced by SyconInstrument was used to control the deposition speed and thickness.

[0129] Example 5

[0130] This embodiment provides a method for preparing a perovskite solar cell, wherein the hole transport layer is prepared from 3PA-DPPyA.

[0131] The difference between Example 5 and Example 4 is that 3PA-TPPyA is replaced by 3PA-DPPyA, and the rest is the same as Example 4.

[0132] Example 6

[0133] This embodiment provides a method for preparing a perovskite solar cell, wherein the hole transport layer is prepared from 3PAPy.

[0134] The difference between Example 6 and Example 4 is that 3PA-TPPyA is replaced by 3PAPy, and the rest is the same as Example 4.

[0135] Comparative Example 2

[0136] The difference between Comparative Example 2 and Example 4 is that 3PA-TPPyA is replaced with a commercial self-assembly material (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz), and the rest is the same as Example 4.

[0137] The performance of the perovskite cells prepared in Examples 4-6 was tested. The current-voltage (JV) characteristics were measured using a Keithley 2400. The test results are shown in Figure 2. Figure 5 As shown. Figure 5 It can be seen that the open circuit voltage of the 3PA-TPPyA-based trans device of Example 4 is 1.185 V and the short circuit current is 25.06 mA / cm 2 , fill factor is 79.28%, and photoelectric conversion efficiency is 23.54%. The open circuit voltage of the 3PA-DPPyA-based trans-device of Example 5 is 0.97 V and the short circuit current is 22.08 mA / cm 2 , the fill factor is 54.86%, and the photoelectric conversion efficiency is 11.75%; the open circuit voltage of the 3PAPy-based trans device of Example 6 is 1.09 V, and the short circuit current is 24.80 mA / cm 2 , the filling factor is 67.07%, and the photoelectric conversion efficiency is 18.22%.

[0138] The open circuit voltage of the trans-type device based on the current mainstream commercial self-assembly molecule 2PACz in Comparative Example 2 is 1.16V and the short circuit current is 24.31mA / cm 2 , the filling factor is 80.50%, and the photoelectric conversion efficiency is 22.71%.

[0139] In contrast, the 3PA-TPPyA-based trans-device of this application achieved a higher open-circuit voltage and a maximum photoelectric conversion efficiency of 23.54%, which is superior to the 22.71% photoelectric conversion efficiency of the 2PACz-based trans-device in Comparative Example 2. Not only does its performance slightly surpass that of the trans-device in Comparative Example 2, which uses the commercial self-assembled material 2PACz as a hole transport layer, but its production cost is also far lower than that of the trans-device in Comparative Example 2.

[0140] The pyridinium salt self-assembling material of this application is low-cost and can be used to prepare a hole transport layer, reducing the production cost of perovskite cells. The pyridinium salt self-assembling material of this application has good wettability, making it easy to spread the perovskite layer as a hole transport layer. No interface rinsing or interface material selection is required to prepare a perovskite film, simplifying the perovskite cell preparation process and further reducing the production cost of perovskite cells. The pyridinium salt self-assembling material of this application has broad application prospects.

[0141] Although this specification has been used to fully describe the present application using general descriptions and specific embodiments, it is obvious to those skilled in the art that modifications or improvements may be made based on the present application. Therefore, such modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in this application.

Claims

1. A pyridinium salt self-assembly material, characterized in that: Its chemical structure is shown in formula (1): (1) wherein at least one of R1, R2 and R3 is an aromatic amine group; The aromatic amine group is , wherein R4 and R5 are each independently selected from a C1-C10 alkoxy group.

2. The pyridinium salt self-assembly material according to claim 1, wherein: The aromatic amine group is .

3. The pyridinium salt self-assembly material according to claim 2, characterized in that R1 and R3 are hydrogen, R2 is ； Its structure is shown in formula (1-2): (1-2)。 4. The pyridinium salt self-assembly material according to claim 2, characterized in that R2 is hydrogen, R1 and R3 are ； Its structure is shown in formula (1-3): (1-3)。 5. Use of the pyridinium salt self-assembly material according to any one of claims 1 to 4 in perovskite solar cells.

6. An inverse perovskite solar cell, characterized in that The invention comprises ITO, a hole transport layer, a perovskite active layer, an electron transport layer and a metal electrode, wherein the hole transport layer is prepared from the pyridinium salt self-assembly material according to any one of claims 1 to 4.

7. The method for preparing an inverse perovskite solar cell according to claim 6, wherein: include: A layer of self-assembled material is spin-coated on indium tin oxide conductive glass as a hole transport layer; Spin coating a layer of perovskite precursor solution on the hole transport layer as a perovskite layer; C is evaporated on the perovskite layer 60 and BCP as electron transport layer; The electron transport layer is evaporated onto metallic silver as an electrode.

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