Method for improving hole transport mobility of nickel oxide and perovskite solar cell

Abstract

The invention discloses a method for improving hole transport mobility of nickel oxide and a perovskite solar cell. According to the invention, a single siloxane-based molecular material is adopted to directly act on the nickel oxide hole transport layer, so that the hole transport capability of nickel oxide is improved, the energy levels of the hole transport layer and the perovskite layer are better matched, the interface contact is improved, and meanwhile, the crystallization quality of the perovskite thin film is improved. Compared with the prior art in which metal alkoxide is added, the method has the advantages that the operation is simple, the cost is saved, in addition, the preferable material in the method directly acts on the nickel oxide hole layer to replace an SAM material commonly used in the traditional process, the hole mobility is greatly improved, and meanwhile, the trans-perovskite solar cell with higher efficiency is obtained.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and more particularly to a method for improving the hole transport and migration rate of nickel oxide and a perovskite solar cell. Background Art

[0002] With the development of society, the demand for energy by humans is increasing. Currently, the most widely used traditional fossil energy is non-renewable. To solve the problem of long-term insufficient energy supply, various countries and regions have accelerated the research on new clean and renewable energy. Among them, the use of solar photovoltaic power generation is one of the key research areas. Perovskite solar cells have developed rapidly due to their advantages of high theoretical limit efficiency of photoelectric conversion, low raw material cost, and easy preparation. Currently, the certified efficiency of inverted perovskite solar cells has reached 26.7%, and the devices exhibit negligible hysteresis and higher stability. The research and development of inverted perovskite solar cells have been rapid.

[0003] In inverted perovskite solar cells, nickel oxide is a currently widely used hole transport layer. However, during the preparation process, Ni 2+ and Ni 3+ defects often exist on the surface of the nickel oxide hole transport layer. These defects will lead to serious non-radiative recombination, reduce the transport efficiency of carriers, and are not conducive to the long-term stability of perovskite devices. Since the siloxane group has a strong chelating effect with nickel oxide, it can effectively passivate the Ni 2+ and Ni 3+ defects on the surface of the nickel oxide hole transport layer, improve the interfacial contact between nickel oxide and the perovskite light-absorbing layer, optimize the energy level structure, enhance the hole transport ability of nickel oxide, reduce carrier non-radiative recombination, and contribute to the improvement of the efficiency and stability of inverted perovskite solar cells. Therefore, the present invention directly introduces a siloxane group material onto the nickel oxide hole transport layer, aiming to enhance the hole transport ability of nickel oxide, obtain a hole transport layer with a high transport rate, and fabricate an efficient perovskite solar cell. Summary of the Invention

[0004] The object of the present invention is to overcome the problem of unbalanced carrier transport caused by the poor hole transport ability of nickel oxide, and provide a method for improving the hole transport and migration rate of nickel oxide and its application in inverted perovskite solar cells. To achieve the object of the present invention, we propose to directly use a siloxane material as a modification layer for nickel oxide, passivate the internal defects of nickel oxide, enhance its ability to extract holes, reduce carrier non-radiative recombination, improve interfacial contact, optimize the energy level structure, and thereby improve the efficiency and long-term stability of the device.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for improving the hole transport mobility of nickel oxide, comprising the following steps:

[0007] (1) Weigh a certain amount of siloxanyl molecular material, disperse it in a solvent, and dissolve it thoroughly by stirring to obtain a siloxanyl molecular material precursor solution;

[0008] (2) Spin-coat the siloxanyl molecular material precursor solution on the nickel oxide thin film, and then perform annealing treatment.

[0009] Preferably, the siloxanyl molecular material in step (1) contains a siloxanyl group, and the molecular structure includes one or more of amino group, carboxyl group, pyrene ring, anthracene ring, carbazole, benzene ring, and methyl group; the solvent is ethanol, methanol, chlorobenzene or ultrapure water.

[0010] Preferably, the concentration of the siloxanyl molecular material in the siloxanyl molecular material precursor solution in step (1) is 0.1 mg / mL to 5.0 mg / mL.

[0011] Preferably, the rotation speed of the spin-coating in step (2) is 2000 - 5000 rpm, and the spin-coating time is 10 - 60 s; the annealing temperature is 0 - 100 °C, and the annealing time is 0 - 60 min.

[0012] Another object of the present invention is to provide a perovskite solar cell, the structure of the solar cell is a p-i-n type inverted structure, and the device sequentially includes a conductive glass, a hole transport layer, a perovskite active layer, an electron transport layer and an electrode from bottom to top;

[0013] Among them, the hole transport layer is a nickel oxide hole transport layer, and the nickel oxide hole transport layer is modified by the above method.

[0014] Preferably, the material of the perovskite active layer is Cs z FA k MA 1-z-k PbI x Br y Cl 3-x-y ; where x = 0 - 3, y = 0 - 3, z = 0 - 3, k = 0 - 3.

[0015] Preferably, the material of the electron transport layer is selected from one or more of tin dioxide, titanium dioxide (TiO2), [6,6]-phenyl-C 61 -butyl methacrylate (PC 61 BM) / [6,6]-phenyl-C 71 -butyl methacrylate (PC 71 BM) / C 60 one or more of them

[0016] More preferably, the material of the electron transport layer is [6,6]-phenyl-C61-butyric acid methyl ester.

[0017] Preferably, the material of the electrode is selected from one or more of silver, copper, and aluminum.

[0018] Specifically, in the present invention, the preparation method of the perovskite solar cell is as follows:

[0019] S1: Clean and dry the glass substrate covered with transparent conductive metal oxide, and perform ozone treatment to improve the surface wettability;

[0020] S2: Spin-coat the nickel oxide precursor solution on the conductive substrate and anneal at a certain temperature;

[0021] S3: Spin-coat the precursor solution of the siloxane-based molecular material on the nickel oxide hole transport layer to obtain a siloxane-modified nickel oxide hole transport layer;

[0022] S4: Prepare a perovskite light-absorbing layer (spin-coating method or vacuum evaporation method) on the siloxane-modified nickel oxide hole transport layer;

[0023] S5: Prepare an electron transport layer on the perovskite light-absorbing layer;

[0024] S6: Prepare an electrode layer on the electron transport layer.

[0025] Through the above technical solutions, compared with the prior art, the present invention has the following beneficial effects:

[0026] In the present invention, by directly using a single siloxane-based molecular material on the nickel oxide hole transport layer, the hole transport ability of nickel oxide is improved, the energy levels of the hole transport layer and the perovskite layer are more matched, the interface contact is improved, and at the same time, the crystallization quality of the perovskite thin film is improved. Compared with the previously published invention patent adding metal alkoxide, the operation of the present invention is simple and the cost is saved. In addition, the preferred material in the present invention directly acts on the nickel oxide hole layer, replacing the commonly used SAM material, greatly improving the hole mobility, and at the same time obtaining a more efficient inverted perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0028] Figure 1 It is a schematic structural diagram of an inverted perovskite solar cell based on a siloxane modification layer of the present invention;

[0029] Figure 2 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 1;

[0030] Figure 3 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 2;

[0031] Figure 4 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 3;

[0032] Figure 5 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 4;

[0033] Figure 6 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 5;

[0034] Figure 7 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 6;

[0035] Figure 8 It is a comparative diagram of the volt-ampere characteristics curve of the perovskite solar cell in Example 7. Detailed implementation manners

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Example 1

[0038] The present invention provides a preferred example 3 - aminopropylmethyldimethoxysilane material applied to a perovskite solar cell, including the following steps:

[0039] 1. The area of the ITO is 1.5 cm × 1.5 cm. The surface treatment sequence is ultrasonic cleaning with a surface cleaner, deionized water, and ethanol, then drying with nitrogen, and finally subjecting the substrate to ultraviolet ozone for 15 minutes;

[0040] 2. Take the prepared nickel oxide nanoparticles and disperse them in deionized water at a concentration of 20 mg / mL;

[0041] 3. Place the ITO in a spin coater, and spin coat the nickel oxide nanoparticle dispersion evenly on the surface of the ITO at a speed of 2000 rpm for 30 s, and then anneal it in air at 200 °C for 10 minutes to obtain a nickel oxide hole transport layer;

[0042] 4. Disperse 3-aminopropylmethyldimethoxysilane in an appropriate amount of ethanol, heat and stir at 60 °C for 1 - 2 h to obtain a 3-aminopropylmethyldimethoxysilane solution;

[0043] 5. Take the 3-aminopropylmethyldimethoxysilane solution obtained in step 4 and spin-coat it on the nickel oxide hole transport layer obtained in step 3, rotate at a speed of 5000 rpm for 30 s, and anneal at 100 °C for 10 min after removal to obtain a 3-aminopropylmethyldimethoxysilane modification layer; the blank control experiment is without adding this modification layer;

[0044] 6. Dissolve FAPbI3 (added with 30% MACl) in a mixed solvent of 1 mL of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 4:1, heat and stir until completely dissolved to prepare a 1.5 M FAPbI3 perovskite solution;

[0045] 7. Take the perovskite solution obtained in step 6 and spin-coat it on the 3-aminopropylmethyldimethoxysilane modification layer obtained in step 5, spin-coat with a process of 1000 rpm (10 s) + 4500 rpm (40 s), and finally add ethyl acetate antisolvent dropwise in the last 10 s, and anneal at 110 °C for 15 min after removal to obtain a FAPbI3 perovskite thin film;

[0046] 8. Dissolve 20 mg of PC61BM in 1 mL of chlorobenzene solvent;

[0047] 9. Take the PC61BM solution obtained in step 8 and spin-coat it on the perovskite thin film obtained in step 7, spin-coat at a speed of 2000 rpm for 30 s to obtain a PC61BM electron transport layer;

[0048] 10. Dissolve 6 mg of BCP in 12 mL of isopropanol solvent and stir to dissolve;

[0049] 11. Take the supernatant of the BCP solution obtained in step 10 and spin-coat it on the surface of the PC61BM obtained in step 9, rotate at a speed of 5000 rpm for 30 s to obtain a buffer layer;

[0050] 12. Deposit a 100 - 110 nm thick metal electrode Ag by thermal evaporation method.

[0051] Experimental effect: Performance tests were carried out on the perovskite solar cell. As Figure 2 shown, under the irradiation of standard light intensity of AM 1.5, 100 mW / cm 2 the J-V performance comparison of the solar cell without using the modification layer (blank control) and the solar cell prepared by modifying nickel oxide with the 3-aminopropylmethyldimethoxysilane solution of this preferred embodiment, using the 3-aminopropylmethyldimethoxysilane solution modification treatment achieved an effective improvement in efficiency (asFigure 2 as shown). In addition, compared with the disclosed patents on treating the perovskite surface with metal alkoxides, the process of the present invention is simple, has lower costs, and has obvious improvement effects.

[0052] In summary, for the application of a 3-aminopropylmethyldimethoxysilane material provided in an embodiment of the present invention on a perovskite solar cell, by separately introducing an ethanol solution of 3-aminopropylmethyldimethoxysilane onto the surface of nickel oxide and applying it at the interface between nickel oxide and perovskite of the perovskite solar cell, a field enhancement structure from P- to P+ is formed, the hole extraction ability is improved, the hole transport is enhanced, and thus the fill factor of the battery is increased; the present invention can also passivate the surface defects of nickel oxide through 3-aminopropylmethyldimethoxysilane, improve the contact between perovskite and the P-type substrate, improve the crystallization quality, reduce the non-radiative recombination of carriers, and thus increase the fill factor to obtain a more efficient perovskite solar cell.

[0053] Example 2

[0054] Compared with the silane coupling agent mentioned in the disclosed patent (CN 114203911A), a concentration of 20 mmol / L was prepared. By spin coating at a rotation speed of 5000 rpm for 50 s, and then heat treatment was carried out at a temperature of 120 °C for 30 minutes. The following data were obtained for the prepared perovskite solar cell:

[0055] Compared with the disclosed patents, the same preparation method and materials in the published patents were used, that is, a silane coupling agent plus an alkoxide was used for comparison with the examples in the present invention:

[0056] The present invention: without mixing alkoxides, only treated with 3-aminopropylmethyldimethoxysilane material, and the obtained optimal efficiency was 24.27%

[0057] Disclosed patent: diethylaminomethyltriethoxysilane;

[0058] N-aminoethyl-3-aminopropylmethyldimethoxysilane;

[0059] (3-aminopropyl)diethoxymethylsilane;

[0060] Performance tests were carried out on the perovskite solar cell, and the results are shown in Table 1 and Figure 3 :

[0061] Table 1 Performance parameters of perovskite solar cells obtained by spin coating different siloxane-based molecular materials and alkoxides on the nickel oxide transport layer

[0062]

[0063] Experimental results: Performance tests were conducted on perovskite solar cells. As Figure 3 shown in Table 1, under the standard light intensity of AM 1.5, 100 mW / cm 2 , the solar cell prepared by modifying nickel oxide with the preferred material 3-aminopropylmethyldimethoxysilane solution of the present invention had the highest efficiency of 24.27%. The efficiency obtained by mixing diethylaminomethyltriethoxysilane and alkoxide in the publicly disclosed invention patent was 22.32%, the efficiency after mixing N-aminoethyl-3-aminopropylmethyldimethoxysilane and alkoxide was 20.32%, and the efficiency after mixing (3-aminopropyl)diethoxymethylsilane and alkoxide was 19.55%. After comparison, it was shown that the preferred material 3-aminopropylmethyldimethoxysilane had a significantly excellent improvement effect, and a high photoelectric conversion efficiency could be achieved without mixing with alkoxide, saving process complexity and material costs.

[0064] Example 3

[0065] The perovskite solar cell was prepared according to the process in Example 1 of the present invention. The siloxanyl molecules were directly spin-coated on the nickel oxide transport layer without mixing with alkoxide. The siloxanyl molecular materials were respectively selected from: 3-aminopropylmethyldimethoxysilane, diethylaminomethyltriethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, (3-aminopropyl)diethoxymethylsilane; the results are shown in Table 2 and Figure 4 :

[0066] Table 2 Performance parameters of perovskite solar cells obtained by spin-coating different siloxanyl molecular material precursor solutions on the nickel oxide transport layer

[0067]

[0068] Experimental results: Performance tests were conducted on perovskite solar cells. As Figure 4 shown in Table 2, under the standard light intensity of AM 1.5, 100 mW / cm 2 , the solar cell prepared by modifying nickel oxide with the preferred material 3-aminopropylmethyldimethoxysilane solution of the present invention had the highest efficiency of 24.27%. The efficiency obtained by using diethylaminomethyltriethoxysilane in the publicly disclosed invention patent was 20.32%, the efficiency of N-aminoethyl-3-aminopropylmethyldimethoxysilane was 18.29%, and the efficiency of (3-aminopropyl)diethoxymethylsilane was 19.95%. After comparison, it was shown that the preferred material 3-aminopropylmethyldimethoxysilane had a significantly excellent improvement effect.

[0069] Example 4

[0070] Optimize the concentration and process of diethylaminomethyltriethoxysilane with the above-mentioned relatively good efficiency (the highest materials and efficiency in the published invention patents), and the results are shown in Table 3 and Figure 5 :

[0071] Table 3 Performance parameters of perovskite solar cells obtained by spin-coating diethylaminomethyltriethoxysilane with different concentrations on the nickel oxide transport layer

[0072]

[0073] Experimental effect: Conduct performance tests on perovskite solar cells. As Figure 5 and shown in Table 3, under AM 1.5, 100 mW / cm 2 standard light intensity, optimize the concentration and process of diethylaminomethyltriethoxysilane with the above-mentioned relatively good efficiency (that is, use the highest materials and efficiency in the published invention patents). The results show that the perovskite solar cell obtained by spin-coating 0.1 mg / mL of diethylaminomethyltriethoxysilane on the nickel oxide transport layer has the highest efficiency, which is 21.74%. The efficiency of the perovskite solar cell obtained by spin-coating 0.2 mg / mL of diethylaminomethyltriethoxysilane on the nickel oxide transport layer is 20.31%. The efficiency of the perovskite solar cell obtained by spin-coating 0.3 mg / mL of diethylaminomethyltriethoxysilane on the nickel oxide transport layer is 19.87%. After comparison, it shows that the perovskite solar cell obtained by spin-coating 0.1 mg / mL of diethylaminomethyltriethoxysilane on the nickel oxide transport layer has the highest efficiency, but the optimized efficiency still does not reach the highest efficiency treated with our preferred material 3-aminopropylmethyldimethoxysilane.

[0074] Example 5

[0075] To highlight the advantages of the present invention, compare with the commonly used hole transport layer modification material SAM molecules. SAM is used as the NiOx interface modification material: The 3-aminopropylmethyldimethoxysilane molecule and its process in the present invention have more advantages. The results are shown in Table 4 and Figure 6 :

[0076] Table 4 Performance parameters of solar cells prepared by modifying nickel oxide with 3-aminopropylmethyldimethoxysilane solution and SAM molecule solution

[0077]

[0078] Experimental effect: Conduct performance tests on perovskite solar cells. As Figure 6 and shown in Table 4, under AM 1.5, 100 mW / cm 2Under standard light intensity, the solar cell prepared by modifying nickel oxide with the preferred material 3-aminopropylmethyldimethoxysilane solution of the present invention has the highest efficiency, which is 24.27%. The efficiency of the solar cell prepared by modifying nickel oxide with the traditional SAM molecular material is 23.30%. After comparison, it shows that the preferred material 3-aminopropylmethyldimethoxysilane has a better improvement effect.

[0079] Example 6

[0080] Using the same process as in Example 1, solar cells prepared by modifying nickel oxide with siloxanyl molecular materials with different groups were compared. The siloxanyl molecular materials were respectively selected from: 3-aminopropylmethyldimethoxysilane, n-decyltrimethoxysilane, hexadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. The results are shown in Table 5 and Figure 7 :

[0081] Table 5 Performance parameters of solar cells prepared by modifying nickel oxide with siloxanyl molecular materials with different groups

[0082]

[0083] Experimental effect: The performance of the perovskite solar cell was tested. As Figure 7 and shown in Table 5, under AM 1.5, 100 mW / cm 2 Under standard light intensity, the solar cell prepared by modifying nickel oxide with the preferred material 3-aminopropylmethyldimethoxysilane solution of the present invention has the highest efficiency, which is 24.52%. The efficiency of the solar cell prepared by modifying nickel oxide with n-decyltrimethoxysilane solution is 23.30%. The efficiency of the solar cell prepared by modifying nickel oxide with hexadecyltrimethoxysilane solution is 23.84%. The efficiency of the solar cell prepared by modifying nickel oxide with 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution is 22.59%. The efficiency of the solar cell prepared by modifying nickel oxide with 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane solution is 22.68%. The results show that the solar cell prepared by modifying nickel oxide with the preferred material 3-aminopropylmethyldimethoxysilane solution has the highest efficiency.

[0084] Example 7

[0085] When the concentration of the best molecule 3-aminopropylmethyldimethoxysilane solution (example) was optimized to 0.2 mg / mL, the best performance was 24.52%.

[0086] The results are shown in Table 6 and Figure 8 :

[0087] Table 6

[0088]

[0089] Experimental results: The performance of the perovskite solar cell was tested. As Figure 8 shown in Table 6, under the standard light intensity of AM 1.5, 100 mW / cm 2 2, the concentration of the 3-aminopropylmethyldimethoxysilane solution with the best efficiency of the preferred example of the present invention was optimized and the process was debugged. The results showed that the perovskite solar cell obtained by spin-coating 0.2 mg / mL of 3-aminopropylmethyldimethoxysilane on the nickel oxide transport layer had the highest efficiency, which was 24.52%.

[0090] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0091] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the hole transport mobility of nickel oxide, characterized in that, It includes the following steps: (1) Weigh a certain amount of siloxane-based molecular material, disperse it in a solvent, and fully dissolve it by stirring to obtain a siloxane-based molecular material precursor solution; (2) Spin-coat the siloxane-based molecular material precursor solution on the nickel oxide thin film, and then perform annealing treatment.

2. The method for improving the hole transport mobility of nickel oxide according to claim 1, characterized in that In step (1), the siloxane-based molecular material contains siloxane groups, and its molecular structure includes one or more of amino group, carboxyl group, pyrene ring, anthracene ring, carbazole, benzene ring, and methyl group; the solvent is ethanol, methanol, chlorobenzene or ultrapure water.

3. A method for improving the hole transport mobility of nickel oxide, according to claim 1, characterized in that, In step (1), the concentration of the siloxane-based molecular material in the siloxane-based molecular material precursor solution is 0.1 mg / mL to 5.0 mg / mL.

4. A method for improving the hole transport mobility of nickel oxide, according to claim 1, characterized in that, In step (2), the rotation speed of the spin-coating is 2000 to 5000 rpm, and the spin-coating time is 10 to 60 s; the annealing temperature is 0 to 100 °C, and the annealing time is 0 to 60 min.

5. A perovskite solar cell, characterized in that, The structure of the solar cell is a p-i-n type inverted structure, and the device sequentially includes a conductive glass, a hole transport layer, a perovskite active layer, an electron transport layer, and an electrode from bottom to top; Among them, the hole transport layer is a nickel oxide hole transport layer, and the nickel oxide hole transport layer is modified by the method described in any one of claims 1-4.

6. The perovskite solar cell according to claim 5, characterized in that, The material of the perovskite active layer is Cs z FA k MA 1-z-k PbI x Br y Cl 3-x-y ; where x = 0 to 3, y = 0 to 3, z = 0 to 3, k = 0 to 3.

7. A perovskite solar cell according to claim 5, wherein The material of the electron transport layer is selected from one or more of tin dioxide, titanium dioxide, [6,6]-phenyl-C61-butyric acid methyl ester, and [6,6]-phenyl-C71-butyric acid methyl ester.

8. A perovskite solar cell according to claim 5, characterized in that, The material of the electrode is selected from one or more of silver, copper, and aluminum.

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