A perovskite solar cell with CSCO nanobowl array as electron transport layer and preparation method thereof

Abstract

The present invention discloses a perovskite solar cell with a CSCO nano bowl array as an electron transport layer and a preparation method thereof, which mainly includes the following steps: cleaning and drying an ITO substrate; preparing a stannous isooctanoate solution; spin coating the stannous isooctanoate solution on an ITO glass; preparing a polystyrene nanosphere suspension; evenly spreading the polystyrene nanosphere suspension on ITO / CSCO; filling the polystyrene nanosphere array gap with a small concentration of stannous isooctanoate solution; removing the polystyrene nanospheres to form a CSCO nano bowl array; preparing a KCl solution; spin coating the KCl solution on the CSCO nano bowl array; spin coating a perovskite precursor solution on a KCl layer; spin coating a Spiro‑OMeTAD solution on a perovskite layer; vacuum evaporation electrodes, thereby obtaining a battery device having a structure of ITO / CSCO / CSCO nano bowl array / KCl / perovskite / Spiro‑OMeTAD / Au. The present invention increases interface contact for rapid electron extraction and transfer, and is the basis for efficient, intelligent and miniaturized devices.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and in particular relates to a perovskite solar cell with a CSCO nanobowl array as an electron transport layer and a preparation method thereof. Background Art

[0002] As environmental pollution and energy crisis continue to intensify, humans are in urgent need of finding a new clean energy source such as solar energy, geothermal energy, wind energy, ocean energy, biomass energy and nuclear fusion energy. Solar energy as a clean energy is considered to be the best way to solve energy problems in the future, and photovoltaic cells that convert solar energy into electrical energy are the most urgently needed energy technology at this stage. Compared with traditional silicon solar cells, perovskite solar cells have received widespread attention due to their high efficiency, low cost and simple preparation process. Summary of the invention

[0003] The present invention makes up for the problem that the transmittance can only depend on the geometry and thickness of the electron transport layer in the past. This application uses the same raw materials to prepare a nanobowl structure array on the dense CSCO electron transport layer, and realizes effective management of the incident light through the nanobowl array, thereby promoting the utilization rate of light by the underlying perovskite film; at the same time, the existence of the bowl-shaped structure increases the contact area between the electron transport layer and the perovskite layer, which is beneficial to the extraction and transfer of photogenerated electrons, and ultimately achieves an improvement in the overall performance of the battery.

[0004] Based on the above purpose, this application adopts the following technical solutions:

[0005] A perovskite solar cell with a CSCO nanobowl array as an electron transport layer and a preparation method thereof, comprising the following steps:

[0006] (1) Clean the ITO substrate and blow dry it with nitrogen;

[0007] (2) preparing a CSCO solution; spin coating the CSCO solution on the ITO glass, annealing, and UV treatment to obtain an ITO / CSCO sample;

[0008] (3) The polystyrene nanosphere solution is evenly spread on the CSCO layer to form a single layer of tightly arranged polystyrene nanosphere arrays; the preparation process of the polystyrene nanosphere array is as follows: the polystyrene nanosphere solution is taken with a syringe and continuously and uniformly injected from one corner of the ITO / CSCO sample with deionized water on the surface, so that the polystyrene nanosphere monolayer covers the entire substrate. After the injection is completed, the deionized water is absorbed with absorbent paper and left to evaporate completely;

[0009] (4) Spin-coating the sample obtained in (3) with a small concentration of CSCO solution in air to fill the gaps in the polystyrene nanosphere array; annealing; after annealing, remove the sample, wash it with a mixture of ethyl acetate and ether, blow dry it with nitrogen, anneal it, and treat it with ultraviolet light to obtain an ITO / CSCO / CSCO nanobowl array sample, which is denoted as: ITO / CSCO / CSCO-NBs sample;

[0010] (5) Spin-coating the sample ITO / CSCO / CSCO-NBs obtained in step (4) with a KCl solution in air and annealing to obtain an ITO / CSCO / CSCO-NBs / KCl sample;

[0011] (6) spin coating the ITO / CSCO / CSCO-NBs / KCl sample obtained in step (5) with a perovskite precursor solution under nitrogen protection, and then annealing to obtain an ITO / CSCO / CSCO-NBs / KCl / perovskite sample;

[0012] (7) spin coating the ITO / CSCO / CSCO-NBs / KCl / perovskite sample obtained in step (6) with a Spiro-OMeTAD solution under nitrogen protection to obtain an ITO / CSCO / CSCO-NBs / KCl / perovskite / Spiro-OMeTAD sample;

[0013] (8) A gold electrode is vacuum evaporated on the Spiro-OMeTAD layer to obtain a solar cell with the structure of ITO / CSCO / CSCO-NBs / KCl / perovskite / Spiro-OMeTAD / Au.

[0014] Further, in step (2), the preparation process of CSCO solution is as follows: take a certain amount of stannous isooctanoate, add n-hexane, and obtain a CSCO n-hexane solution with a mass ratio of 10-15 wt%. In step (2), annealing refers to annealing at 95-105 °C for 15-25 min. The spin coating amount of CSCO solution is 15-25 µL / cm 2 .

[0015] Furthermore, in step (3), the preparation process of the polystyrene nanosphere solution is as follows: the polystyrene microsphere original solution, ethanol and acetone are mixed in a volume ratio of 1: (0.2-0.4): (0.6-0.8), and shaken to obtain the solution; the injection volume of the polystyrene nanosphere solution is 2-3 µL / cm 2 , the volume ratio of the polystyrene nanosphere solution and the deionized water carried on the surface of the ITO / CSCO sample is 1:(100~200).

[0016] Further, in step (4), the preparation process of the low concentration CSCO solution is as follows: take a certain amount of stannous isooctanoate, add n-hexane, and obtain a CSCO n-hexane solution with a mass ratio of 2-4 wt%. In step (4), the first annealing refers to annealing at 110-130 °C for 1-3 min, and the second annealing refers to annealing at 95-105 °C for 15-25 min. The spin coating amount of the low concentration CSCO solution is 20-30 µL / cm 2 .

[0017] Further, in step (5), the preparation process of KCl solution is as follows: take KCl, add deionized water, and obtain 1~2mg / mL KCl solution. In step (5), annealing refers to annealing at 100~110℃ for 5~20min. The spin coating amount of KCl solution is 20~30µL / cm 2 .

[0018] Furthermore, in step (6), the perovskite precursor solution is specifically Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.85 Br 0.15 ) 3 (denoted as CsFAMA) perovskite precursor solution, the specific preparation process is as follows: CsI, FAI, MAI, PbI 2 and PbBr 2 Dissolve in a DMF:DMSO mixed solution with a volume ratio of 8.5:1.5 at a molar ratio of 0.05:0.81:0.14:0.78:0.22, and the molar volume ratio of CsFAMA is 1.3~1.5 mol / L, and then stir for 10~15 hours to obtain a perovskite precursor solution; in step (6), annealing refers to annealing at 120~130 °C for 5~15 minutes. The spin coating amount of the perovskite precursor solution is 5~10µL / cm 2 .

[0019] Furthermore, in step (7), the preparation process of the Spiro-OMeTAD solution is as follows: take a certain amount of Spiro-OMeTAD, add chlorobenzene, 4-tert-butylpyridine, and lithium salt (bistrifluoromethanesulfonyl imide lithium acetonitrile solution), stir for 10-15 hours, and obtain a Spiro-OMeTAD solution. The spin coating amount of the Spiro-OMeTAD solution is 4-6 µL / cm 2 .

[0020] The perovskite solar cell with the CSCO nanobowl array prepared by the above preparation method as the electron transport layer, specifically, the CSCO layer thickness is 30~50nm, the perovskite layer thickness is 400~600nm, the Spiro-OMeTAD layer thickness is 150~200nm, and the gold electrode thickness is 80~100nm.

[0021] The method of the present invention increases interface contact and can be used for rapid electron extraction and transfer, and is the basis for making devices more efficient, intelligent and miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the battery of the present invention;

[0023] Figure 2 The current density-voltage characteristic curves of the batteries of Example 1 and Comparative Example 1;

[0024] Figure 3 is the SEM image of the nanospheres of Example 1;

[0025] Figure 4 This is the SEM image of the CSCO nanobowl;

[0026] Figure 5 This is the SEM image of the perovskite surface without nanobowl array structure;

[0027] Figure 6 This is an SEM image of the perovskite surface with a nanobowl array structure. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0029] Example 1

[0030] A method for preparing a perovskite solar cell using a CSCO nanobowl array as an electron transport layer, the process is as follows:

[0031] (1) Two concentrations of CSCO solutions were prepared in air: 110 mg of stannous 2-ethylhexanoate was dissolved in 890 mg of n-hexane to prepare a solution with a mass concentration of 11 wt%; 30 mg of stannous 2-ethylhexanoate was dissolved in 970 mg of n-hexane to prepare a solution with a mass concentration of 3 wt%.

[0032] (2) Preparation of polystyrene microsphere solution in air: Take 100 μL of polystyrene microsphere original solution with a microsphere diameter of 500 nm (the polystyrene microsphere original solution is a 2.5 wt% polystyrene microsphere ethanol solution), 30 μL of ethanol, and 70 μL of acetone, mix them and sonicate for 30 min.

[0033] (3) Prepare CsFAMA perovskite precursor solution in a nitrogen glove box: CsI, FAI, MAI, PbI 2 and PbBr 2 The molar ratio of CsFAMA was 0.05:0.81:0.14:0.78:0.22, dissolved in a DMF:DMSO mixed solution with a volume ratio of 8.5:1.5, and the molar volume ratio of CsFAMA was 1.4 mol / L. After stirring at room temperature for 12 h, the perovskite precursor solution was obtained. In all steps using the glove box, the water and oxygen contents were ensured to be less than 0.1 ppm.

[0034] (4) Prepare Spiro-OMeTAD solution in a nitrogen glove box: weigh 72.5 mg of Spiro-OMeTAD powder in a small sample bottle, add 1 mL of chlorobenzene, 35 μL of lithium bis(trifluoromethanesulfonyl)imide acetonitrile solution (lithium salt, Li-TFSI, solution concentration is 260 mg / mL) and 28.5 μL of 4-tert-butylpyridine, stir for 12 h to obtain Spiro-OMeTAD solution.

[0035] (5) An ITO substrate with an area of ​​2.0 cm × 2.0 cm was ultrasonically cleaned with deionized water, acetone, isopropanol, and deionized water in sequence, each for 20 min. Finally, the ITO substrate was blown dry with nitrogen.

[0036] (6) Take 80 μL of 11wt% CSCO solution and spin coat it on ITO glass in air at a speed of 7000 rpm for 2 s. After spin coating, anneal it at 100°C for 20 min. After annealing, treat it with UV light (main wavelength 185nm, temperature 40~50°C) for 1 hour to obtain an ITO / CSCO sample with a CSCO layer thickness of 40nm.

[0037] (7) Inject 1 mL of deionized water onto the surface of the ITO / CSCO sample, and use a syringe to take 10 µL of polystyrene microsphere solution and slowly and evenly inject it from one corner of the ITO / CSCO sample. The injection should not be interrupted during this process, and the microspheres should cover the entire surface of the sample. During the injection process, the sample can be slightly fixed with the syringe needle to prevent it from moving. After the injection is completed, quickly absorb the deionized water with absorbent paper and continue to stand until the deionized water is completely evaporated to obtain an ITO / CSCO / nanosphere array sample. The sample is scanned by electron microscopy. The results are shown in the figure. Figure 3 As shown, Figure 3This indicates that an array of nanospheres with uniform size and neat arrangement has been obtained. Take 100 μL of 3wt% CSCO solution and drop it on the sample covered with microspheres. After standing for 5 s, spin coat at a speed of 5000 rpm for 10 s. After spin coating, anneal at 120 °C for 1 min, then use a mixed liquid of ethyl acetate and ether with a volume ratio of 1:1 to clean for 10 s, then blow dry the sample with a nitrogen gun, anneal at 100 °C for 5 min, and treat with ultraviolet (main wavelength 185nm, temperature 40~50 °C) for 30 min to obtain ITO / CSCO / CSCO-NBs sample. Scan the sample with an electron microscope, and the results are as follows: Figure 4 As shown, Figure 4 This shows that the nanobowl array obtained after processing the nanosphere array is still arranged neatly and has uniform size.

[0038] (8) Take 100 μL of KCl solution in air and spin coat it on the ITO / CSCO / CSCO-NBs sample at a speed of 3000 rpm for 10 s. After spin coating, anneal at 105 °C for 10 min to obtain the ITO / CSCO / CSCO-NBs / KCl sample.

[0039] (9) The ITO / CSCO / CSCO-NBs / KCl sample from step (8) was transferred to a nitrogen glove phase. Under the protection of nitrogen, 25 μL of CsFAMA perovskite precursor solution was spin-coated at a low speed of 1000 rpm and a high speed of 4500 rpm for 4 s and 20 s respectively. The sample was annealed at 125 °C for 10 min to obtain an ITO / CSCO / CSCO-NBs / KCl / CsFAMA sample with a perovskite layer thickness of 500 nm. The sample was scanned by electron microscopy. Figure 6 shown.

[0040] (10) Spin coat 22 μL of Spiro-OMeTAD solution on the ITO / CSCO / CSCO-NBs / KCl / CsFAMA sample at 4500 rpm for 15 s and allow to dry naturally to obtain an ITO / CSCO / CSCO-NBs / KCl / CsFAMA / Spiro-OMeTAD sample with a Spiro-OMeTAD layer thickness of 165 nm.

[0041] (11) Finally, the sample obtained in step (10) is transferred to a vacuum evaporation instrument, and a gold electrode with a thickness of 80-100 nm is evaporated to complete the battery preparation. The obtained battery sample has the structure of ITO / CSCO / CSCO-NBs / KCl / CsFAMA / Spiro-OMeTAD / Au, and its structural schematic diagram is shown in the figure. Figure 1 shown.

[0042] Comparative Example 1

[0043] As a reference, the process (1) to (11) of Example 1 was repeated, while the process (2) and (7) were omitted to obtain a reference battery sample, whose structure was: ITO / CSCO / KCl / CsFAMA / Spiro-OMeTAD / Au. During the preparation process, the annealed perovskite layer was scanned by electron microscope, and the results were as follows: Figure 5 shown.

[0044] At AM 1.5 G, 100 mW cm −2 The performance of the batteries of Example 1 and Comparative Example 1 was tested under simulated sunlight. Figure 2 , Figure 2 It is proved that the nanobowl array has a positive effect on improving the battery performance, among which the open circuit voltage of the battery ( V oc ), short-circuit current density ( J sc ) and fill factor (FF) were improved to varying degrees, and ultimately the battery’s power conversion efficiency (PCE) increased from 22.19% to 23.54%.

[0045] from Figure 5 and Figure 6 The SEM image of the perovskite surface shows that Figure 5 Perovskite films based on nanobowl-free arrays, Figure 6 The perovskite surface with nanobowl arrays shown in the figure has larger, continuous and uniform grains, which is one of the important evidences of its higher battery PCE.

[0046] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for preparing a perovskite solar cell with a CSCO nanobowl array as an electron transport layer, characterized in that: The following steps are involved: (1) Clean the ITO substrate and blow dry it with nitrogen; (2) Prepare CSCO solution; The CSCO solution was spin-coated on the ITO glass, annealed, and UV-treated to obtain an ITO / CSCO sample; The preparation process of CSCO solution is as follows: take stannous isooctanoate, add n-hexane, and obtain a CSCO solution with a mass ratio of 10-15 wt%; (3) The polystyrene nanosphere solution is evenly spread on the CSCO layer to form a single layer of tightly arranged polystyrene nanosphere arrays. The preparation process of the polystyrene nanosphere array is as follows: use a syringe to take the polystyrene nanosphere solution and continuously and evenly inject it from one corner of the ITO / CSCO sample with deionized water on the surface to make the polystyrene nanosphere monolayer cover the entire substrate. After the injection, use absorbent paper to absorb the deionized water and let it stand until the deionized water evaporates completely. The preparation process of the polystyrene nanosphere solution is as follows: the original polystyrene microsphere solution, ethanol and acetone are mixed in a volume ratio of 1: (0.2~0.4): (0.6~0.8) and shake well to obtain the result. The injection volume of the polystyrene nanosphere solution is 2~3 µL / cm 2 , the volume ratio of the polystyrene nanosphere solution and the deionized water carried on the surface of the ITO / CSCO sample was 1:(100~200); (4) Spin-coating the sample obtained in (3) with CSCO solution in air to fill the gaps in the polystyrene nanosphere array; annealing; after annealing, remove the sample, clean it with a mixture of ethyl acetate and ether, blow dry it with nitrogen, anneal it, and treat it with ultraviolet light to obtain an ITO / CSCO / CSCO nanobowl array sample, which is denoted as: ITO / CSCO / CSCO-NBs sample; The preparation process of CSCO solution is as follows: take stannous isooctanoate, add n-hexane, and obtain a CSCO n-hexane solution with a mass ratio of 2-4 wt%; (5) Spin-coating the sample ITO / CSCO / CSCO-NBs obtained in step (4) with a KCl solution in air and annealing to obtain an ITO / CSCO / CSCO-NBs / KCl sample; (6) spin coating the ITO / CSCO / CSCO-NBs / KCl sample obtained in step (5) with a perovskite precursor solution under nitrogen protection, and then annealing to obtain an ITO / CSCO / CSCO-NBs / KCl / perovskite sample; (7) spin coating the ITO / CSCO / CSCO-NBs / KCl / perovskite sample obtained in step (6) with a Spiro-OMeTAD solution under nitrogen protection to obtain an ITO / CSCO / CSCO-NBs / KCl / perovskite / Spiro-OMeTAD sample; (8) A gold electrode is vacuum evaporated on the Spiro-OMeTAD layer to obtain a solar cell with the structure of ITO / CSCO / CSCO-NBs / KCl / perovskite / Spiro-OMeTAD / Au.

2. The method for preparing a perovskite solar cell using the CSCO nanobowl array as an electron transport layer according to claim 1, characterized in that: In step (2), annealing refers to annealing at 95-105°C for 15-25 min.

3. The method for preparing a perovskite solar cell using the CSCO nanobowl array as an electron transport layer according to claim 1, characterized in that: In step (4), the first annealing refers to annealing at 110-130°C for 1-3 min, and the second annealing refers to annealing at 95-105°C for 15-25 min.

4. The method for preparing a perovskite solar cell using the CSCO nanobowl array as an electron transport layer according to claim 1, characterized in that: In step (4), the volume ratio of ethyl acetate to ether is 1:

1.

5. The method for preparing a perovskite solar cell using the CSCO nanobowl array as an electron transport layer according to claim 1, characterized in that: In step (5), the preparation process of the KCl solution is as follows: take KCl and add deionized water to obtain a 1-2 mg / mL KCl solution. In step (5), annealing refers to annealing at 100-110 °C for 5-20 min.

6. The method for preparing a perovskite solar cell using the CSCO nanobowl array as an electron transport layer according to claim 1, characterized in that: In step (6), the perovskite precursor solution is specifically Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.85 Br 0.15 )3 Perovskite precursor solution, the specific preparation process is as follows: solid powders of CsI, FAI, MAI, PbI2 and PbBr2 are added to a DMF:DMSO mixed solvent with a volume ratio of 8.5:1.5 at a molar ratio of 0.05:0.81:0.14:0.78:0.22, Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.85 Br 0.15 )3 has a molar volume ratio of 1.3-1.5 mol / L, and then stirred for 10-15 hours to obtain a perovskite precursor solution; in step (6), annealing refers to annealing at 120-130 °C for 5-15 min.

7. A perovskite solar cell using the CSCO nanobowl array prepared by the preparation method according to any one of claims 1 to 6 as an electron transport layer.

8. The perovskite solar cell according to claim 7, characterized in that: The thickness of the CSCO layer is 30~50nm, the thickness of the perovskite layer is 400~600nm, the thickness of the Spiro-OMeTAD layer is 150~200nm, and the thickness of the gold electrode is 80~100nm.

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