Method for post-processing carbon-based mesoporous perovskite solar cell through nanoimprint technology

Abstract

The invention discloses a method for carrying out plane imprinting and different pattern imprinting on a carbon-based mesoporous perovskite solar cell through a nanoimprinting technology, and the duration time, temperature and pressure intensity of imprinting are controlled during imprinting, so that the performance, stability and the like of the carbon-based mesoporous perovskite solar cell can be improved. Post-treatment is carried out on the cell by adopting two imprinting methods, the first kind of plane imprinting can enable the contact between layers to be tighter, so that charge transfer impedance is reduced, recombination between interfaces is reduced, after plane imprinting, perovskite can be recrystallized, the crystallization quality of the perovskite is improved, defects of the perovskite are reduced, and the performance of the perovskite is improved. Therefore, the performance and stability of the battery are improved. According to the second method, a patterned imprint plate is used for imprint, a channel can be formed on the surface so as to help rapid transmission of carriers, and the imprint can also reduce transmission impedance, reduce recombination between interfaces and improve the crystal quality of perovskite, so that the performance and stability of the cell are improved.

Description

Technical Field

[0001] The present invention relates to a manufacturing technology in the field of perovskite solar cells, and in particular to a method for post-processing a carbon-based mesoporous perovskite solar cell by nanoimprinting technology. Background Art

[0002] In recent years, the main factor hindering the commercialization of carbon-based mesoporous perovskite solar cells is the low photoelectric conversion efficiency. Therefore, in order to realize the commercial large-scale production and application of carbon-based mesoporous perovskite solar cells, it is urgent to improve their photoelectric conversion efficiency. Studies have shown that the factors that restrict the photoelectric conversion efficiency of carbon-based mesoporous perovskite solar cells include: (1) the energy levels of the perovskite film and the carbon electrode do not match, the contact is not tight, and the carbon electrode has poor conductivity and low carrier mobility; (2) the growth quality of the perovskite film crystal in the mesoporous layer is poor, there are many defect states, and the recombination is serious. At present, methods such as solvent engineering, adding additives, and gas phase assistance have been used. These methods have well demonstrated that the photoelectric conversion efficiency of perovskite can be improved by affecting the filling growth of perovskite. Secondly, it was found in the study that external factors such as pressure and heat have a great influence on the growth of grains, so the crystallization quality of perovskite can be improved by changing the pressure and heat of the external environment. Therefore, the present invention proposes to post-process the carbon-based mesoporous perovskite solar cells through nanoimprint technology. Nanoimprint technology can improve the crystallization quality of perovskite through pressure and heat, make the contact between battery layers closer, reduce transmission impedance, reduce recombination between interfaces, and promote rapid transport of carriers. Summary of the invention

[0003] To solve the above technical problems, the present invention adopts a carbon-based mesoporous perovskite solar cell with a four-mesoporous layer architecture, and uses nanoimprinting technology to post-process the mesoporous perovskite solar cell filled with perovskite, so that the contact between each layer structure is closer, the contact impedance and the charge recombination at the interface are reduced, and the perovskite is recrystallized, thereby enhancing the crystallinity of the perovskite, increasing the formed perovskite particles, forming a perovskite with fewer morphological defects, making the formed perovskite more dense, reducing the recombination between interfaces, thereby improving the photoelectric conversion efficiency and stability of the carbon-based mesoporous perovskite solar cell, and adjusting the temperature, pressure and time of the imprinting to regulate the various performances of the battery. In order to achieve the above purpose, the present invention adopts the following technical solutions.

[0004] See also Figure 1First, prepare the mesoporous electron transport layer TiO2 film, the mesoporous support layer ZrO2 film, the mesoporous hole transport layer NiO film, and the back electrode C film, and then fill the perovskite precursor solution. First dry the battery, and finally use nanoimprint technology to post-process the battery. Two technologies are used for post-processing. One is to use flat imprint technology. This method uses a silicon plate with no pattern on the surface for flat pressing, so that the contact between the battery layers is closer, so as to achieve the purpose of reducing the contact impedance and reduce the composite between the interfaces. Flat pressing can also make the perovskite recrystallize, thereby enhancing the crystallinity of the perovskite, increasing the formed perovskite particles, and forming fewer defects in the morphology of the perovskite. The formed perovskite is more dense, thereby reducing the composite between the interfaces. Secondly, because the stamp and the battery are in close contact, the perovskite can also be prevented from being degraded at high temperatures during this imprinting process, so this flat pressing technology can enhance the performance and stability of the battery. The second method is to use patterned imprinting technology for imprinting. This method uses different silicon plates with patterns for imprinting. This imprinting method can form different channels on the surface, thereby helping the rapid transportation of carriers, reducing the recombination between interfaces, and improving the performance of the battery. This patterned imprinting will also have the effect of planar imprinting.

[0005] In the implementation of these two pressing methods, batteries with different performance parameters can be formed by controlling the temperature, pressure and time during pressing. The temperature is controlled at 100°C, 150°C and 180°C respectively, the pressure is controlled at 3MPa, 5Mpa and 7Mpa respectively, and the time is controlled at 10 minutes, 15 minutes and 20 minutes respectively. By controlling the temperature, pressure and time during pressing, batteries with different degrees of close contact can be formed, as well as perovskites with different morphologies, thus forming batteries with different performance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to explain the technical solution more clearly, the following briefly introduces the drawings required for use.

[0007] Figure 1 The figure is the overall flow chart of the preparation method.

[0008] Figure 2 This is the flow chart for the preparation of mesoporous TiO2 thin films.

[0009] Figure 3 This is the flow chart for the preparation of mesoporous ZrO2 thin films.

[0010] Figure 4 This is the flow chart for the preparation of mesoporous NiO thin films.

[0011] Figure 5 Flow chart for preparing the back electrode C film.

[0012] Figure 6 Flowchart for perovskite filling.

[0013] Figure 7 Flowchart for processing imprinted silicon substrates.

[0014] Figure 8 This is a flow chart for printing.

[0015] Fig. 9 Schematic diagram of stamping. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0017] First, prepare the mesoporous TiO2 film, see Figure 2 The method includes steps S1 to S3.

[0018] S1: Mix TiO2 slurry and pinene alcohol, stir, and then perform ultrasonic dispersion, wherein the mass ratio of TiO2 slurry to pinene alcohol is 1:4, to obtain TiO2 slurry for thin film printing.

[0019] S2: Use a screen printer to print TiO2 slurry on the surface of the substrate, let it stand until the slurry flows evenly, and place the substrate on a hot table for drying, setting the temperature to 70°C.

[0020] S3: After the TiO2 slurry is dried, the substrate is transferred to a titanium plate hot plate at 500°C for sintering for 40 minutes, and then left to cool.

[0021] Then prepare the mesoporous ZrO2 film, see Figure 3 The method includes steps S1 to S4.

[0022] S1: Weigh 12g ZrO2 powder, 6g ethyl cellulose and 36g terpineol, and then weigh 2mL acetic acid, and put all into a ball mill.

[0023] S2: Add an appropriate amount of anhydrous ethanol to the ball mill, stir evenly, and place it in a planetary ball mill for 48 hours, and then perform rotary evaporation at 45°C to remove excess ethanol.

[0024] S3: Use a screen printer to print ZrO2 slurry on the surface of the substrate prepared in the previous step.

[0025] S4: Wait for the slurry to be evenly distributed, place the substrate on a hot plate for drying, and set the temperature to 70°C.

[0026] The second step is to prepare mesoporous NiO thin films. Figure 4 The method includes steps S1 to S4.

[0027] S1: Weigh 3 g NiO powder, 15 g ethyl cellulose, 10 g terpineol, and 2 mL acetic acid, and put them all into a ball mill.

[0028] S2: Add an appropriate amount of anhydrous ethanol to the ball mill, stir evenly, and place it in a planetary ball mill for 48 hours, and then perform rotary evaporation at 45°C to remove excess ethanol.

[0029] S3: Use a screen printer to print NiO slurry on the surface of the substrate prepared in the previous step.

[0030] S4: Wait for the slurry to be evenly distributed, place the substrate on a hot plate for drying, and set the temperature to 70°C.

[0031] Finally, prepare the back electrode C film, see Figure 5 The method includes steps S1 to S4.

[0032] S1: Weigh 26g of graphite and 8g of carbon black and add them into a ball mill respectively, and then add 6.4g of ZrO2 powder and 4.8g of ethyl cellulose powder respectively.

[0033] S2: Add 90g of pinene alcohol and an appropriate amount of anhydrous ethanol to a ball mill, put it into a planetary ball mill and mill it for 24 hours, then perform rotary evaporation at 45°C to remove excess ethanol.

[0034] S3: Use a screen printer to print the carbon slurry on the surface of the substrate prepared in the previous step, and place the substrate on a hot plate for drying, with the temperature set at 70°C.

[0035] S4: After the TiO2 slurry is dried, the substrate is transferred to a titanium plate hot plate at 400°C for sintering for 30 minutes, and then left to cool.

[0036] After the mesoporous scaffold is prepared, the perovskite precursor solution is filled in. Figure 6 The method includes steps S1 to S4.

[0037] S1: Take out the substrate cooled to about 100°C.

[0038] S2: Add the perovskite precursor solution from the edge of the mesoporous support layer ZrO2 thin film layer into the mesoporous support, and cover the rest of the area with high-temperature tape.

[0039] S3: Let the filled battery stand for 5 to 10 minutes to allow the solution to diffuse throughout the battery.

[0040] S4: Place the entire battery in a constant temperature convection oven for annealing, set the temperature to 50°C, and continue for 2 hours.

[0041] Finally, the battery is post-processed using the imprinting technology. First, the imprinted silicon plate is processed. See Figure 7 The method includes steps S1 to S3.

[0042] S1: First, clean the silicon plate with acetone at 50°C for 5 minutes, then rinse with isopropanol for 1 minute, and dry with nitrogen.

[0043] S2: Treat the silicon plate with perfluorododecyltrichlorosilane (FDTS) in n-heptane solvent for 5 minutes, then immerse the silicon plate in acetone for 1 minute and dry it with nitrogen gas.

[0044] S3: Bake at 100°C for 20 minutes to remove moisture in perfluorododecyltrichlorosilane (FDTS) and increase the hydrophobicity of the silicon plate.

[0045] Then nanoimprinting is performed, see Figure 8 The method includes steps S1 to S3.

[0046] S1: Place the battery under the silicon plate, wherein the silicon plate can be a flat silicon plate without pattern or a silicon plate with different patterns.

[0047] S2: Then adjust the temperature, pressure and duration of nanoimprinting. The temperature is controlled at 100°C, 150°C and 180°C respectively, the pressure is controlled at 3MPa, 5Mpa and 7Mpa respectively, and the duration is controlled at 10 minutes, 15 minutes and 20 minutes respectively, and start imprinting.

[0048] S3: Finally, the silicon plate is demoulded to complete the imprinting.

[0049] When the mesoporous perovskite solar cell is planarly stamped, due to the heating effect during the planar stamping process, the compressed perovskite grains extend outward under the action of directional force to form larger grains. Therefore, under planar stamping, the perovskite has a higher density, better morphology, and higher crystallinity, and due to the Z-direction compressive stress in the geometric space, the perovskite grains are guided to form a preferred orientation, thereby reducing the recombination between interfaces and promoting the rapid transport of carriers. In addition, due to the effect of pressure, the contact between each layer is closer, achieving the purpose of reducing contact impedance and reducing the recombination between interfaces. When patterned stamping is performed, not only can the effect of planar stamping be achieved, but also channels with different patterns can be formed on the electrode surface, thereby promoting the rapid transport of carriers and reducing the recombination between interfaces.

[0050] The schematic diagram of the present invention is shown in FIG. Fig. 9, where different patterned silicon plates can be used, such as continuously combined triangles, quadrilaterals, pentagons, or even irregularly arranged patterns, to form different channels on the surface to help the rapid transport of carriers. In addition, by changing the pressure, temperature, and duration of the imprinting process, batteries with different parameters, such as different carrier mobility and conductivity, can be prepared.

[0051] By post-processing the carbon-based mesoporous perovskite solar cell with nanoimprint technology, the contact between each layer of the structure can be made closer, the contact impedance and the charge recombination at the interface can be reduced, and the perovskite can be recrystallized by imprinting, thereby enhancing the crystallinity of the perovskite, increasing the formed perovskite particles, forming a perovskite with fewer morphological defects, and reducing the recombination between interfaces, thereby improving the photoelectric conversion efficiency and stability of the carbon-based mesoporous perovskite solar cell, and by adjusting the temperature, pressure and duration of the imprinting, the various performances of the battery can be regulated. The successful implementation of the present invention can significantly improve the photoelectric conversion efficiency of the carbon-based mesoporous perovskite solar cell and the stability of the battery, and the present invention does not require photolithography or etching, and can be well applied to the commercialization of carbon-based mesoporous perovskite solar cells.

Claims

1. A method for post-processing a mesoporous perovskite solar cell by nanoimprinting technology, characterized in that: include: Referring to Figure 1, firstly, the mesoporous electron transport layer TiO2 film, the mesoporous support layer ZrO2 film, the mesoporous hole transport layer NiO film, and the back electrode C film are prepared, and then the perovskite precursor solution is filled. The battery is first dried, and finally the battery is post-processed by nanoimprinting technology. Two technologies are used for post-processing respectively. One is the flat imprinting technology. This method uses a silicon plate with no pattern on the surface for flat pressing, so that the contact between the battery layers is closer, so as to achieve the purpose of reducing the contact impedance and reduce the composite between the interfaces. Flat pressing can also make the perovskite recrystallize, thereby enhancing the crystallinity of the perovskite, increasing the formed perovskite particles, and forming fewer defects in the morphology of the perovskite. The formed perovskite is more dense, thereby reducing the composite between the interfaces. Secondly, because the stamp and the battery are in close contact, the perovskite can also be prevented from being degraded at high temperatures during this imprinting process, so the performance and stability of the battery are enhanced by this flat pressing technology. The second method is to use patterned imprinting technology for imprinting. This method uses different silicon plates with patterns for imprinting. This imprinting method can form different channels on the surface, thereby helping the rapid transport of carriers, reducing the recombination between interfaces, and improving the performance of the battery. This patterned imprinting will also have the effect of planar imprinting. In the implementation of these two imprinting methods, batteries with different performance parameters can be formed by controlling the temperature, pressure, and time during imprinting. The temperature is controlled at 100°C, 150°C, and 180°C, respectively. The pressure is controlled at 3MPa, 5Mpa, and 7Mpa, respectively, and the time is controlled at 10 minutes, 15 minutes, and 20 minutes, respectively. By controlling the temperature, pressure, and time during imprinting, batteries with different degrees of close contact can be formed, as well as perovskites with different morphologies, thereby forming batteries with different performance and stability.

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