Preparation method of perovskite solar cell and application thereof

Abstract

The application belongs to the technical field of solar cells, and discloses a preparation method of a perovskite solar cell and application thereof. The preparation method of the perovskite solar cell comprises preparation of a perovskite layer, and a perovskite precursor solution used in the preparation process of the perovskite layer comprises a phosphatidylcholine additive. The preparation process of the perovskite layer comprises annealing treatment, the annealing temperature is 140-160 DEG C, and the annealing time is 3-5 minutes. The application adjusts the nucleation and crystal growth process of the perovskite by introducing the phosphatidylcholine additive and high-temperature rapid annealing process (140-160 DEG C, 3-5 minutes), effectively passivates ion defects in the perovskite layer, reduces trap state density, inhibits non-radiative recombination in the perovskite solar cell, and greatly improves the photovoltaic performance of a large-area carbon-based perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and specifically relates to a method for preparing perovskite solar cells and their applications. Background Technology

[0002] Under the global climate change and "dual carbon" goals, solar cells, as a sustainable and clean energy technology, have received widespread attention for their development. Compared with traditional crystalline silicon solar cells, perovskite solar cells have advantages such as low cost, solution processability, and large-scale production.

[0003] Ag, Al, and Au are common electrodes in perovskite solar cells, but the vapor deposition process for metal electrodes is energy-intensive, time-consuming, and costly. Furthermore, Ag and Al readily react with halide anions migrating in the perovskite to form resistive compounds, such as AgI and AlI3 (see: Y. Kato et al, Adv. Mater. Interfaces. 2015, 2, 1500195). The enthalpy of formation of Au-I is much higher than that of Ag-I and Al-I, but Au can diffuse into the perovskite to form deep-level Au. Pb Antisite defects can serve as nonradiative recombination centers (see: K. Domanski et al., ACS Nano. 2016, 10, 6, 6306-6314). Carbon-based solar cells have advantages such as full printing, low cost, and high stability in air environments, making them strong competitors in photovoltaic devices. It is worth noting that the insufficient hole-pulling capability of carbon electrodes places higher demands on the light absorption capacity and further charge transport of the perovskite layer.

[0004] Since its initial report, the efficiency of perovskite solar cells has improved from 3.8% (see: A. Kojima et al., J. Am. Chem. Soc. 2009, 131, 6050-6051) to 25.7% (see: https: / / www.nrel.gov / pv / cell-efficiency.html). However, there is still a gap between the efficiency of large-format modules and small-format cells. This efficiency gap is mainly due to photoelectric losses caused by internal defects in large-area perovskite films. Recent studies have shown that the photoelectric conversion efficiency of perovskite solar cells decreases with increasing area. For example, the effective area is 40 cm². 2 At that time, the corresponding photoelectric conversion efficiency is generally no more than 10.2%.

[0005] The perovskite light-absorbing layer is a key component of perovskite solar cells, and its thin-film crystal quality and carrier mobility are crucial to the photoelectric performance of perovskite solar cells. However, large-area perovskite layers often contain defects such as film inhomogeneity, which prevents effective improvement in cell efficiency.

[0006] Therefore, there is an urgent need to provide a new method for preparing perovskite solar cells. The perovskite solar cells prepared by this method not only have a large area but also high photoelectric conversion efficiency, which will be very beneficial to the promotion and application of new energy sources. Summary of the Invention

[0007] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for fabricating perovskite solar cells and their applications. The perovskite solar cells fabricated by the method of this invention achieve a photoelectric conversion efficiency exceeding 15% when the effective area is large. Specifically, for example, an effective area of ​​40 cm²... 2 At that time, the corresponding photoelectric conversion efficiency is 15-16.5%.

[0008] The inventive concept of this invention is as follows: This invention uses phosphatidylcholine as an additive to prepare a perovskite precursor solution, and combines it with specific annealing conditions (140-160℃, 3-5 minutes) during the perovskite layer preparation process to obtain a large-area perovskite solar cell with high photoelectric conversion efficiency.

[0009] By adding phosphatidylcholine as an additive to perovskite materials, the crystallization kinetics of perovskite can be controlled, and ionic defects in perovskite can be passivated, thus solving the problem of poor photoelectric performance of existing large-area perovskite solar cells.

[0010] This study found that utilizing phosphatidylcholine additives in conjunction with a high-temperature rapid annealing process can significantly improve the photoelectric conversion efficiency of large-area perovskite solar cells. On one hand, the long alkyl chains in the phosphatidylcholine additives can effectively suppress solution flow during solvent evaporation from a hydrodynamic perspective, improving the uniformity of the perovskite layer; on the other hand, the PO4 in the phosphatidylcholine additives... - I can occupy the surface of the perovskite lattice - Vacancies are created, thus passivating ionic defects and effectively improving the photovoltaic performance of perovskite solar cells. Furthermore, specific annealing conditions during perovskite layer preparation are a crucial factor in significantly improving the photoelectric conversion efficiency of perovskite solar cells.

[0011] The first aspect of the present invention provides a method for preparing a perovskite solar cell.

[0012] Specifically, a method for preparing a perovskite solar cell includes the preparation of a perovskite layer, wherein the perovskite precursor solution used in the preparation of the perovskite layer includes a phosphatidylcholine additive, and the preparation of the perovskite layer includes an annealing treatment at a temperature of 140-160°C for 3-5 minutes.

[0013] Preferably, the phosphatidylcholine additive has the following structural formula:

[0014]

[0015] Wherein, R1 and R2 each represent a long alkyl chain C. n H 2n+1 , where n is an integer greater than 1.

[0016] More preferably, R1 and R2 each represent a long alkyl chain with 10-25 carbon atoms.

[0017] Preferably, the annealing temperature is 145-155℃ and the annealing time is 3-5 minutes.

[0018] Preferably, the concentration of the phosphatidylcholine additive in the perovskite precursor solution is 0.1-2.5 mg / mL; more preferably, the concentration of the phosphatidylcholine additive is 0.1-2.0 mg / mL.

[0019] Preferably, the perovskite precursor solution includes a perovskite material, which is an organic-inorganic hybrid or all-inorganic metal halide perovskite material.

[0020] More preferably, the perovskite material has the general formula ABX3, where A is CH3NH3. + NH2CH=NH + CH3C(NH2)2 + Cs + 、Rb + K + Na + Li + At least one of them, B is Pb 2+ Sn 2+ 、Ge 2+ Cu 2+ Mn 2+ Fe 2+ Co 2+ Ni 2+ Zn 2 + Mg 2+ At least one of them, X is F - Cl -,Br - I - BF4 - SCN - PF6 - HCOO - CH3COO - (Ac - ), TFSI - PO4 3- CO3 2- NO3 - SO4 2- At least one of them.

[0021] Preferably, the concentration of perovskite material in the perovskite precursor solution is 0.3-3.5 mol / L; more preferably, the concentration of perovskite material in the perovskite precursor solution is 0.5-3 mol / L.

[0022] Preferably, a method for fabricating a perovskite solar cell includes the following steps:

[0023] An electron transport layer solution is printed or coated onto a transparent conductive substrate and then annealed to obtain an electron transport layer. The perovskite precursor solution is then printed or coated onto the surface of the electron transport layer and annealed to obtain a perovskite layer. Finally, a carbon electrode solution is printed or coated onto the substrate and annealed to obtain a carbon electrode, thus obtaining the perovskite solar cell.

[0024] Preferably, the transparent conductive substrate includes a substrate and a transparent electrode.

[0025] Preferably, the substrate is a rigid substrate or a flexible substrate.

[0026] Preferably, the rigid substrate is made of glass.

[0027] Preferably, the flexible substrate is made of any one of polyimide, polyethylene terephthalate (PET), or polyethersulfone resin.

[0028] Preferably, the transparent electrode is any one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or aluminum-doped zinc oxide (AZO).

[0029] Preferably, the electron transport layer solution comprises at least one of SnO2 or TiO2.

[0030] Preferably, the electron transport layer solution further includes at least one of guanidine hydrochloride or biguanide hydrochloride.

[0031] Preferably, the annealing temperature during the preparation of the electron transport layer is 120-160°C, and the annealing time is 20-30 minutes.

[0032] Preferably, the hot stage temperature during the preparation of the electron transport layer is 60-120°C.

[0033] Preferably, the hot stage temperature during the preparation of the perovskite layer is 100-130°C.

[0034] Preferably, the annealing temperature during the preparation of the carbon electrode is 100-120°C, and the annealing time is 10-15 minutes.

[0035] Preferably, the hot stage temperature during the preparation of the carbon electrode is 20-30°C.

[0036] A second aspect of the present invention provides a perovskite solar cell.

[0037] A perovskite solar cell, prepared by the above method, comprises, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite layer, and a carbon electrode.

[0038] Preferably, the thickness of the electron transport layer is 40-220 nm; more preferably, the thickness of the electron transport layer is 50-200 nm.

[0039] Preferably, the thickness of the perovskite layer is 500-2500 nm; more preferably, the thickness of the perovskite layer is 450-2550 nm.

[0040] Preferably, the thickness of the carbon electrode is 1800-21000 nm; more preferably, the thickness of the carbon electrode is 2000-20000 nm.

[0041] A third aspect of the present invention provides an application of a perovskite solar cell.

[0042] The above-mentioned perovskite solar cells are used in the field of new energy.

[0043] Preferably, the new energy field includes new energy vehicles.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] (1) By introducing phosphatidylcholine additives and using a high-temperature rapid annealing process (140-160℃, 3-5 minutes), the present invention effectively regulates the nucleation and crystal growth process of perovskite, effectively passivates ion defects in the perovskite layer, reduces the density of trapped states, and suppresses non-radiative recombination inside the perovskite solar cell, thereby greatly improving the photovoltaic performance of large-area carbon-based perovskite solar cells.

[0046] (2) The thickness of the electron transport layer, perovskite layer and carbon electrode of the present invention can be adjusted by the height of the scraper from the table and the solution concentration. The preparation of each layer of the perovskite solar cell can be carried out in an all-air environment.

[0047] (3) This invention has the advantages of simple and flexible process, good controllability, and low mass production cost, and can effectively solve the problem of poor photoelectric performance of large-area carbon-based perovskite solar cells. Using carbon electrodes instead of traditional Ag, Al, and Au electrodes can significantly reduce production costs and is conducive to the industrial mass production of perovskite solar cells. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell prepared in Example 1 of the present invention;

[0049] Figure 2 SEM images of perovskite layers with and without DSPC.

[0050] Figure 3 XPS images of perovskite layers with and without DSPC;

[0051] Figure 4 PL (fluorescence) images of perovskite layers with and without DSPC;

[0052] Figure 5 XRD patterns of perovskite layers with and without DSPC at different addition concentrations;

[0053] Figure 6 XRD patterns of perovskite layers with and without DSPC at different annealing temperatures;

[0054] Figure 7 This is a current-voltage curve of the perovskite solar cell prepared in Example 1 of the present invention;

[0055] Figure 8 This is a graph showing the retention of photoelectric efficiency of the perovskite solar cell prepared in Example 1 of the present invention after being placed at room temperature (25°C) for 6 weeks. Detailed Implementation

[0056] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0057] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0058] The phosphatidylcholine additive DSPC (C) used in the following examples 44 H 88 The model number of NO8P is P1138, and the DLPC (C) 32 H 64 The NO8P model number is P1263, and both can be obtained directly through commercial channels.

[0059] Example 1: Fabrication of perovskite solar cells

[0060] A method for fabricating a perovskite solar cell includes the following steps:

[0061] Preparation of perovskite precursor solution: Weigh 0.1240 g CH3NH3I (methylamine iodide), 0.0722 g CH5NH2I (formamidin iodide), and 0.5532 g PbI2 (lead iodide) and mix them. Add 800 mL DMF (N,N-dimethylformamide) and 200 mL DMSO (dimethyl sulfoxide). Stir magnetically at room temperature (25°C) for 1 h. Then add 40 μL of phosphatidylcholine additive DSPC (C 44 H 88 NO8P) solution (20 mg DSPC / 1 mL DMF), stirred for 3 h;

[0062] Preparation of electron transport layer solution:

[0063] SnO2 (15% aqueous colloidal dispersion) was mixed with deionized water at a volume ratio of 1:4 and stirred at room temperature (25°C) for 1 hour to obtain a mixture. Then, guanidine hydrochloride (5 mg / mL) was added and stirred for 3 hours.

[0064] Polyimide tape was applied along the etched lines onto an ITO conductive glass substrate. The substrate was then irradiated with UV light for 20 minutes. The polyimide tape was removed to obtain a transparent conductive substrate. An electron transport layer solution was then coated onto the transparent conductive substrate at a speed of 300 cm / min. The substrate was annealed at 150°C for 30 minutes to obtain the electron transport layer. Next, a perovskite precursor solution was coated onto the surface of the electron transport layer and annealed. During annealing, the hot plate temperature was set to 130°C, the annealing temperature was 150°C, and the annealing time was 5 minutes to obtain the perovskite layer. Finally, a carbon electrode solution (the carbon electrode solution is conductive carbon paste from Guangzhou Saidi Technology Development Co., Ltd., product model DD-10, which is a conductive ink made by uniformly distributing carbon-based particles in thermoplastic resin) was coated at a speed of 300 cm / min and annealed at 120°C for 15 minutes to obtain the carbon electrode, thus obtaining the perovskite solar cell.

[0065] A perovskite solar cell, prepared by the above method, comprises, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite layer, and a carbon electrode.

[0066] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell prepared in Example 1 of the present invention; Figure 1 In the diagram, 100 represents a transparent conductive substrate, 200 represents an electron transport layer, 300 represents a perovskite layer, and 400 represents a carbon electrode.

[0067] Example 2: Fabrication of perovskite solar cells

[0068] The difference between Example 1 and Example 2 is that Example 2 uses the same concentration and amount of phosphatidylcholine additive DLPC (C 32 H 64 NO8P) solution replaces the phosphatidylcholine additive DSPC (C) in Example 1. 44 H 88 The NO8P solution was used, and the rest of the process was the same as in Example 1.

[0069] Example 3: Fabrication of Perovskite Solar Cells

[0070] Compared with Example 1, the difference in Example 3 is that FTO glass substrate is used instead of transparent conductive substrate in Example 1 in Example 3, while the rest of the process is the same as in Example 1.

[0071] Comparative Example 1

[0072] Compared with Example 1, the difference in Comparative Example 1 is that no phosphatidylcholine additive DSPC (C) was added when preparing the perovskite precursor solution in Comparative Example 1. 44 H 88 The NO8P solution was used, and the rest of the process was the same as in Example 1.

[0073] Comparative Example 2

[0074] Compared with Example 1, the difference of Comparative Example 2 is that in the preparation process of the perovskite layer in Comparative Example 2, the annealing temperature is 150°C and the annealing time is 15 min, while the rest of the process is the same as in Example 1.

[0075] Comparative Example 3

[0076] Compared with Example 1, the difference of Comparative Example 3 is that in the preparation process of the perovskite layer in Comparative Example 3, the annealing temperature is 100°C and the annealing time is 5 min, while the rest of the process is the same as in Example 1.

[0077] Product effectiveness test

[0078] 1. Testing the effect of phosphatidylcholine additive DSPC on perovskite layers (also known as perovskite films).

[0079] A perovskite layer (denoted as "With DSPC", indicating a perovskite layer with DSPC) was prepared using the method of Example 1. Then, a perovskite layer (denoted as "Pristine", indicating a perovskite layer without DSPC) was prepared in the same manner as in Example 1, but without the addition of phosphatidylcholine additive DSPC.

[0080] To verify the effect of DSPC on the regulation of perovskite crystallization properties and the passivation of defect states, perovskite films with and without DSPC were compared.

[0081] Figure 2 SEM images of perovskite layers with and without DSPC; from Figure 2 The SEM images show that the addition of DSPC significantly increases the grain size of the perovskite, which is beneficial for carrier migration. Furthermore, the surface of the perovskite layer prepared with DSPC is smoother.

[0082] Figure 3 XPS images of perovskite layers with and without DSPC; from Figure 3 ( Figure 3 In the graph, the horizontal axis "Binding Energy" represents the binding energy, and the vertical axis "Intensity" represents the intensity. It can be seen that there is a perovskite layer with DSPC and Pb 4f... 5 / 2 and Pb 4f 7 / 2 The peaks all shift towards directions with lower binding energies, indicating that PO4 in DSPC... - Through coordination, Pb is introduced into the perovskite... 2+ By providing lone pairs of electrons, trap defects are passivated, effectively suppressing nonradiative recombination in thin films.

[0083] Figure 4 PL diagrams for perovskite layers with and without DSPC; Figure 4 ( Figure 4 The horizontal axis "Wavelength" represents wavelength, and the vertical axis "PL Intensity" represents fluorescence intensity. The wavelength of the excitation incident light used in this figure is 405 nm. Figure 4 This further confirms Figure 3 The conclusion.

[0084] Figure 5 ( Figure 5 The horizontal axis “2Theta (degree)” represents 2θ (degree), and the vertical axis “Intensity” represents intensity. These are XRD patterns of perovskite layers with and without DSPC at different addition concentrations. Figure 6 ( Figure 6The x-axis "2Theta (degree)" represents 2θ (degrees), and the y-axis "Intensity" represents intensity. These are XRD patterns of perovskite layers with and without DSPC at different annealing temperatures. Figure 5 The optimal DSPC addition concentration is given. Figure 6 The optimal annealing temperature for the perovskite layer is given. From Figure 5-6 It can be seen that the appropriate content of phosphatidylcholine additive and the annealing temperature of perovskite film are crucial to the formation of perovskite layer with high crystallinity.

[0085] Figure 7 This is a current-voltage curve of the perovskite solar cell prepared in Example 1 of the present invention;

[0086] Figure 8 This is a graph showing the retention of photoelectric efficiency of the perovskite solar cell prepared in Example 1 of the present invention after being placed at room temperature (25°C) for 6 weeks.

[0087] The perovskite solar cell prepared in step 1 was placed under a solar simulator (one-sun AM 1.5G 100mW·cm²). -2 Intensity (Enlitech SS-X50 solar simulator), using a Keysight source meter (model B2901A), was used to scan the current and voltage of the perovskite solar cell, obtaining the current (I)-voltage (V) curve, as shown below. Figure 7 ( Figure 7 The horizontal axis ("Voltage" represents voltage, and "Current" represents current) is shown in the diagram. According to the formula PCE(%) = Jsc * Voc * FF / P in The photoelectric conversion efficiency of the perovskite solar cell was obtained, where Jsc is the short-circuit current density, Voc is the open-circuit voltage, FF is the fill factor, and P is the power factor. in The input power is denoted by , and PCE is the photoelectric conversion efficiency. The results show that the fabricated perovskite solar cell achieves a photoelectric conversion efficiency as high as 16.09% (active area = 40 cm²). 2 Perovskite solar cells exhibit good stability. After being placed in a dark, air-conditioned environment at room temperature (25±5℃) and relative humidity (25±5%) for 6 weeks, their photoelectric efficiency still remains above 90% of the initial value. The results are as follows... Figure 8 ( Figure 8 The horizontal axis “Time (week)” represents time (week), and the vertical axis “Normalized PCE” represents normalized photoelectric conversion efficiency, as shown in the figure, indicating that the perovskite solar cell prepared by this invention has good stability.

[0088] The photoelectric performance of the perovskite solar cells prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the results are shown in Table 1.

[0089] Table 1

[0090]

[0091] The specific calculation process for photoelectric conversion efficiency in Example 1 is as follows:

[0092] PCE (%) = Jsc * Voc * FF / P in =110.373 / (40 / 8)*1.103*0.661 / 100=16.09%.

[0093] As can be seen from Table 1, the photoelectric performance of the perovskite solar cells prepared in Examples 1-3 is significantly better than that of the perovskite solar cells prepared in Comparative Examples 1-3.

[0094] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention, as long as they achieve the technical effects of the present invention by the same means, should be included within the scope of protection of the present invention. Within the scope of protection of the present invention, the technical solutions and / or implementation methods can have various modifications and variations.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: An electron transport layer solution is printed or coated onto a transparent conductive substrate and then annealed to obtain an electron transport layer. A perovskite precursor solution is then printed or coated onto the surface of the electron transport layer and annealed to obtain a perovskite layer. A carbon electrode solution is then printed or coated onto the substrate and annealed to obtain a carbon electrode, thus obtaining the perovskite solar cell. The perovskite precursor solution used in the preparation of the perovskite layer includes phosphatidylcholine additive, and the preparation of the perovskite layer includes annealing treatment at a temperature of 145-155°C for 3-5 minutes. The molecular formula of the phosphatidylcholine additive is C 44 H 88 NO8P or C 32 H 64 NO8P.

2. The preparation method according to claim 1, characterized in that, In the perovskite precursor solution, the concentration of the phosphatidylcholine additive is 0.1-2.5 mg / mL.

3. The preparation method according to claim 1, characterized in that, The perovskite precursor solution includes perovskite material, which is an organic-inorganic hybrid or all-inorganic metal halide perovskite material.

4. The preparation method according to claim 1, characterized in that, The concentration of perovskite material in the perovskite precursor solution is 0.3-3.5 mol / L.

5. A perovskite solar cell, characterized in that, The perovskite solar cell, prepared by any one of claims 1-4, comprises, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite layer, and a carbon electrode.

6. The application of the perovskite solar cell according to claim 5 in the field of new energy.

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