Indoor low-light solar cell and preparation method thereof

Abstract

The application discloses an indoor weak-light solar cell and a preparation method thereof. The preparation method comprises the following steps: preparing a hole transport layer on a transparent substrate; preparing an Al2O3-PMMA film by spin coating a mixed Al2O3-PMMA solution on the hole transport layer; transferring to a dry air glove box, spin coating a wide-bandgap perovskite mixed solution, dropping an EA-PMMA mixed solution on the rotating wide-bandgap perovskite film 5-10 seconds before the spin coating wide-bandgap perovskite mixed solution procedure ends, annealing at 95-100 DEG C for 15-20 min to crystallize the perovskite film, and sequentially preparing a passivation layer, an electron transport layer and a back electrode. The application can effectively improve the internal effective ohmic contact of the photovoltaic device, improve the composition uniformity of the high-content bromine wide-bandgap perovskite film, reduce the non-ohmic leakage current loss, and improve the weak-light performance of the wide-bandgap perovskite photovoltaic cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to an indoor low-light solar cell and its preparation method. Background Technology

[0002] Although crystalline silicon solar cells dominate the photovoltaic market due to their mature industrial chain, high photoelectric conversion efficiency, and low cost, their low transparency and poor performance in low light conditions prevent them from meeting the needs of various applications such as high-efficiency, long-duration power generation under wide light intensity and building-integrated photovoltaics (BIPV). Perovskite materials, with their tunable bandgap and flexible control over spectral absorption range and intensity, can be applied to photovoltaic data acquisition systems with a wide light intensity range. This is particularly significant for designing smart windows, building integration for both indoor and outdoor applications, and integrated Internet of Things (IoT) systems.

[0003] Multicomponent perovskite thin films offer a wide tunable bandgap range, enabling their photovoltaic devices to achieve high efficiency and long-lasting power generation under varying light intensities. Under low light conditions, the open-circuit voltage and fill factor of perovskite photovoltaic devices depend on the non-ohmic and ohmic leakage currents within the device, respectively. Effectively improving the ohmic contact within the photovoltaic device, reducing series resistance while increasing parallel resistance, is key to enhancing the low-light performance of wide-bandgap perovskite photovoltaic cells. Furthermore, during the thin-film fabrication process, wide-bandgap perovskite films with high bromine content (molar content exceeding 20%) easily cause halogen phase separation, leading to significant losses in open-circuit voltage and fill factor under low-light conditions. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a method for preparing indoor low-light solar cells, which can effectively improve the effective ohmic contact inside the photovoltaic device, improve the compositional uniformity of the wide-bandgap perovskite thin film with high bromine content, reduce non-ohmic leakage current loss, and improve the low-light performance of wide-bandgap perovskite photovoltaic cells.

[0005] Another objective of this invention is to prepare an indoor low-light solar cell using the above-described preparation method.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a method for preparing an indoor low-light solar cell, comprising the following steps:

[0008] Preparation of PMMA-Al2O3 solution: Dissolve Al2O3 dispersion in isopropanol solvent to prepare solution A; dissolve PMMA in isopropanol solvent to prepare solution B; mix solution A and solution B to obtain PMMA-Al2O3 solution;

[0009] Preparation of perovskite precursor solution: according to Cs x FA y MA 1-x-y PbI z Br 3-z Weigh CsI, FAI, PbI2, MABr, and PbBr2, where 0.04≤x≤0.06, 0.6≤y≤0.7, and 2≤z≤2.5. Dissolve CsI in DMSO to prepare a CsI solution. Dissolve FAI and PbI2 in a mixed solvent DMF / DMSO to prepare a FAPbI3 solution. Dissolve MABr and PbBr2 in a mixed solvent DMF / DMSO to prepare a MAPbBr3 solution. Mix the CsI solution, FAPbI3 solution, and MAPbBr3 solution to construct a wide-bandgap perovskite precursor solution.

[0010] Fabrication of solar cells:

[0011] A hole transport layer was prepared on a transparent substrate; an Al2O3-PMMA thin film was prepared by spin-coating an Al2O3-PMMA solution onto the hole transport layer; the film was transferred to a dry glove box, and a wide-bandgap perovskite mixed solution was spin-coated onto the Al2O3-PMMA thin film; 5-10 seconds before the end of the spin-coating process, an EA-PMMA mixed solution was dropped onto the rotating wide-bandgap perovskite thin film; the perovskite thin film was then annealed at 95-100℃ for 15-20 min to crystallize the film and obtain Cs. x FA y MA 1-x-y PbI z Br 3-z -PMMA film;

[0012] In Cs x FA y MA 1-x-y PbI z Br 3-z A passivation layer, an electron transport layer, and a back electrode are sequentially fabricated on a PMMA thin film.

[0013] Preferably, the concentration of the CsI solution is 1.3–1.5 M; the concentration of the FAPbI3 solution is 1.3–1.5 M; and the concentration of the MAPbBr3 solution is 1.3–1.5 M.

[0014] Preferably, the fabrication of the hole transport layer on the transparent substrate specifically involves:

[0015] After cleaning and ozone treatment of the ITO glass substrate, NiO was prepared on the ITO glass substrate at room temperature using radio frequency magnetron sputtering. x Layers, to obtain ITO / NiO x Substrate; then PTAA solution was spin-coated onto ITO / NiO.x Hole transport layer NiO fabricated on substrate x / PTAA film.

[0016] Preferably, the PTAA solution is spin-coated onto ITO / NiO. x Preparation of ITO / NiO on substrate x / PTAA film, specifically:

[0017] Spin-coating PTAA solution onto ITO / NiO x On an ITO glass substrate, a hole transport layer NiO is obtained by heating to 110-120℃. x / PTAA film.

[0018] Preferably, the step of spin-coating the Al2O3-PMMA solution onto the hole transport layer to prepare the Al2O3-PMMA film specifically involves spin-coating the Al2O3-PMMA solution onto the hole transport layer and heating it to 110-120°C to obtain the Al2O3-PMMA film.

[0019] Preferably, the preparation of the passivation layer specifically involves:

[0020] A PEAI solution with isopropanol as solvent was deposited on a wide-bandgap perovskite film at a spin speed of 3900-4100 rpm for 27-31 s, followed by annealing at 95-100℃ for 8-11 min. The concentration of the PEAI solution was 0.8-1.2 mg / mL.

[0021] Preferably, the electron transport layer is prepared as follows: a 30-40 nm thick C60 film is deposited in a metal thermal evaporation apparatus, and the sample after C60 film deposition is placed in an atomic layer deposition apparatus to prepare a SnO2 film. The deposition cycle is 180-200 cycles and the deposition time is 15-20 min.

[0022] Preferably, the back electrode is prepared as follows: thermally evaporates Ag to a thickness of 200-250 nm.

[0023] Preferably, the concentration of PMMA in the EA-PMMA mixed solution is 0.2-1 mg / mL.

[0024] Preferably, the PMMA-Al2O3 solution is prepared as follows: 1-1.2 mL of Al2O3 dispersion is dissolved in 50-52 mL of isopropanol solvent to prepare solution A; 0.05-0.07 mg of PMMA is dissolved in 1-1.2 mL of isopropanol solvent to prepare solution B; 1-1.2 mL of solution B is mixed with 5-5.2 mL of solution A to obtain the PMMA-Al2O3 solution.

[0025] The present invention also provides an indoor low-light solar cell, which is prepared by the method described above.

[0026] Specifically, the structure of the indoor low-light solar cell is as follows:

[0027] ITO / NiO x / PTAA / Al2O3-PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA / PEAI / C 60 / SnO2 / Ag.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) The indoor low-light solar cell of the present invention employs the PMMA-Al2O3 composite interface layer of the present invention, inserted between the wide-bandgap perovskite and hole transport layer interface, and simultaneously uses a wide-bandgap perovskite-PMMA bulk heterojunction thin film of the specific composition of the present invention as a light absorption layer. This improves the effective ohmic contact inside the photovoltaic device, reduces the series resistance while increasing the parallel resistance, and enhances the low-light performance of the wide-bandgap perovskite photovoltaic cell. For example, in the embodiments of the present invention, the output power of the bandgap perovskite photovoltaic cell reaches 132.02 μW cm⁻¹ under the conditions of 1,000 lux and 3,000 K. -2 Its low-light efficiency reaches 43.91%, and its V oc FF and J sc The voltages achieved were 1.07 V, 83.62%, and 148.15 μA / cm, respectively. 2 At 600 lux and 3,000 K, the battery output power reached 80.231 μW / cm². -2 Its low-light efficiency reaches 44.28%, and its V oc FF and J sc The values ​​reached 1.04V, 82.83%, and 93.36μA / cm, respectively. 2 .

[0030] (2) The indoor low-light solar cell of the present invention uses the PMMA-Al2O3 composite interface layer of the present invention and the wide-bandgap perovskite-PMMA bulk heterojunction film of the present invention as the light absorption layer, so that the component distribution in the film is more uniform, thereby reducing the non-ohmic leakage current loss. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an indoor low-light solar cell according to Embodiment 1 of the present invention.

[0032] Figure 2 This is a JV curve of the indoor low-light solar cell of Embodiment 1 of the present invention under different irradiance levels such as indoor low-light LEDs.

[0033] Figure 3 The JV curves of the solar cells of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention are shown in the low light conditions (1,000 lux, 3,000 K) indoors.

[0034] Figure 4 The series resistance (a) and parallel resistance (b) of the devices in Comparative Examples 1, 2 and 1 of the present invention are shown.

[0035] Figure 5 These are fluorescence scanning comparison images of the perovskite films of Comparative Example 1, Comparative Example 2, and Example 1 of the present invention.

[0036] Figure 6 The images show a comparison of the fluorescence spectra of the perovskite films in Comparative Examples 1, 2, and 1 of the present invention.

[0037] Figure 7 The graph shows the change in crystallization over time for perovskite films with different PMMA contents.

[0038] Figure 8 The values ​​represent the water contact angles of perovskite films with different PMMA contents, where (a) to (d) represent PMMA concentrations in ethyl acetate of 0 mg / mL, 0.2 mg / mL, 0.5 mg / mL, and 1 mg / mL, respectively. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0040] Example 1

[0041] like Figure 1 As shown, the indoor low-light solar cell of this embodiment includes an ITO glass substrate 1 and a hole transport layer (NiO2). x / PTAA)2、PMMA-Al2O3 composite interface layer 3、Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA film 4, passivation layer (PEAI) 5, electron transport layer (C60 / SnO2) 6, back electrode (Ag) 7.

[0042] The method for fabricating an indoor low-light solar cell in this embodiment includes the following steps:

[0043] Preparation of PMMA-Al2O3 solution: Take 1 mL of Al2O3 dispersion (particle size 30 nm, dissolved in isopropanol solvent, concentration 20 wt%) and dissolve it in 50 mL of isopropanol solvent to prepare solution A; take 0.05 mg of PMMA and dissolve it in 1 mL of isopropanol solvent to prepare solution B; take 1 mL of solution B and mix it with 5 mL of solution A to obtain PMMA-Al2O3 solution.

[0044] Preparation of perovskite precursor solution: according to Cs x FA y MA 1-x-y PbI z Br 3-z Weigh CsI, FAI, PbI2, MABr, and PbBr2, where x = 0.05, y = 0.70, and z = 2.15 in this example; prepare a CsI solution by dissolving CsI in DMSO solvent; prepare a FAPbI3 solution by dissolving FAI and PbI2 in a mixed solvent DMF / DMSO; prepare a MAPbBr3 solution by dissolving MABr and PbBr2 in a mixed solvent DMF / DMSO; and construct a wide-bandgap perovskite precursor solution by mixing the CsI solution, FAPbI3 solution, and MAPbBr3 solution.

[0045] The fabrication process of solar cells: First, the ITO glass substrate is ultrasonically cleaned sequentially with detergent, deionized water, and IPA for 10 minutes, dried with N2, and then treated with ozone for minutes. NiO is then prepared on a NiO target at room temperature using radio frequency magnetron sputtering. x Layer. Then, the PTAA solution was in an ITO / NiO layer at 4500 rpm. x ITO / NiO was obtained by spin-coating the substrate for 28 seconds and heating it on a hot stage at 115°C for 18 minutes. x / PTAA film, then the prepared Al2O3-PMMA solution is applied to ITO / NiO at a speed of 4000-4500 rpm. x ITO / NiO was obtained by spin-coating a PTAA thin film onto a substrate for 28 seconds and heating at 115°C for 20 minutes. x / PTAA / Al2O3-PMMA film. The prepared ITO / NiO... x The PTAA / Al2O3-PMMA solution was transferred to a dry glove box, and then a wide-bandgap perovskite mixed solution was spin-coated. Ten seconds before the end of the program, 220 μL of the EA-PMMA mixed solution (0.5 mg / mL) was dropped onto the rotating wide-bandgap perovskite film. The perovskite film was then crystallized by annealing at 98-100 °C for 18-20 min to obtain ITO / NiO. x / PTAA / Al2O3-PMMA / Csx FA y MA 1-x-y PbI z Br 3-z -PMMA film. Next, a 1 mg / mL PEAI solution with isopropanol as the solvent was deposited on the wide-bandgap perovskite film at 4000 rpm for 30 s, followed by annealing at 100°C for 10 min. The sample was then transferred to a metal thermal evaporation apparatus to deposit a 35 nm thick C60 layer as an electron transport layer. The sample with the C60 film deposited was then placed in an atomic layer deposition apparatus to prepare a SnO2 film, with 190 deposition cycles and a deposition time of 18 min. Finally, a 220 nm thick Ag layer was thermally evaporated. The final perovskite solar cell structure is: ITO / NiO. x / PTAA / Al2O3-PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA / PEAI / C 60 / SnO2 / Ag.

[0046] Comparative Example 1

[0047] The perovskite solar cell structure prepared in this comparative example is: ITO / NiO. x / PTAA / Al2O3 / Cs x FA y MA 1-x- y PbI z Br 3-z / PEAI / C 60 / SnO2 / Ag, wherein the Al2O3 solution is prepared as follows: 1-1.2 mL of Al2O3 dispersion is dissolved in 50-52 mL of isopropanol solvent to prepare an Al2O3 solution; in the preparation of wide-bandgap perovskite films, EA-PMMA mixed solution is not used for treatment.

[0048] Apart from the differences mentioned above, the other features of this comparative example are the same as those of Example 1.

[0049] Comparative Example 2

[0050] The perovskite solar cell structure prepared in this comparative example is: ITO / NiO. x / PTAA / Al2O3-PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z / PEAI / C 60 / SnO2 / Ag. In the preparation of wide-bandgap perovskite films, EA-PMMA mixed solutions are not used for treatment.

[0051] Apart from the differences mentioned above, the other features of this comparative example are the same as those of Example 1.

[0052] The perovskite solar cells of Example 1, Comparative Example 1, and Comparative Example 2 were tested for low-light performance.

[0053] Figure 2 Table 1 shows the performance of the indoor low-light solar cell of Example 1 of the present invention under different irradiance levels such as indoor low-light LEDs. The results show that the indoor low-light solar cell of Example 1 has excellent low-light performance.

[0054] Figure 3 Table 2 shows a performance comparison of the solar cells of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention under weak light conditions (1,000 lux, 3,000 K) in an indoor environment. It can be seen that, compared with Comparative Example 1, Comparative Example 2 uses an EA-PMMA mixed solution for treatment during the preparation of the wide-bandgap perovskite thin film, which has no effect on the open-circuit voltage. However, Example 1, by combining the wide-bandgap perovskite-PMMA bulk heterojunction film and the PMMA-Al2O3 composite interface layer, significantly improves the open-circuit voltage. The above results indicate that using only the wide-bandgap perovskite-PMMA bulk heterojunction film cannot improve the open-circuit voltage; it is necessary to combine the wide-bandgap perovskite-PMMA bulk heterojunction film and the PMMA-Al2O3 composite interface layer to achieve this. Meanwhile, the comparison shows that in the forward scan test, the solar cells of Example 1 and Comparative Example 2 are equivalent to Comparative Example 1, with varying degrees of improvement in FF and PCE parameters; while in the reverse scan test, the FF and PCE of Comparative Example 2 are slightly lower than those of Comparative Example 1, while Example 1 shows a significant improvement compared to Comparative Example 1.

[0055] Figure 4 Figures (a) and (b) show the series and parallel resistances of the solar cells of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention, respectively. The results show that Embodiment 1 has a low series resistance (R0). s = 1.37 Ohm cm -2 The series resistances of Comparative Examples 1 and 2 are relatively high, namely: R s = 1.94 Ohm cm -2 and R s = 1.67 Ohm cm -2 Example 1 has a high parallel resistance (R). sh =2000 Ohm cm -2 While Comparative Examples 1 and 2 have low parallel resistance: Rsh =840 Ohm cm -2 and R sh =1113 Ohm cm -2 The results show that by combining wide-bandgap perovskite-PMMA bulk heterojunction film and PMMA-Al2O3 composite interface layer, the ohmic and non-ohmic leakage currents are low, the series resistance is minimal, the parallel resistance is maximum, the non-ohmic leakage current and ohmic leakage current losses are minimal, and the low-light performance is the best.

[0056] Figure 5 Images (a), (b), and (c) show comparative fluorescence scanning images of the perovskite films of Comparative Example 1, Comparative Example 2, and Example 1, respectively. The results show that by combining a wide-bandgap perovskite-PMMA bulk heterojunction film and a PMMA-Al2O3 composite interface layer, the film has low defect states and the wide-bandgap perovskite film has a high compositional uniformity distribution.

[0057] Figure 6 The fluorescence spectra of the perovskite films of Comparative Example 1, Comparative Example 2 and Example 1 of the present invention are shown. The results show that by combining the wide-bandgap perovskite-PMMA bulk heterojunction film and PMMA-Al2O3 composite interface layer, the film has low defect states, which is beneficial to charge separation and transport.

[0058] Figure 7 The image shows the change in perovskite film crystallization over time after adjusting the concentration of PMMA in ethyl acetate in Example 1 of the present invention. Figure 7 The longer crystallization time of the wide-bandgap perovskite thin film containing PMMA in Example 1 is beneficial for the growth of thin film crystals.

[0059] Figure 8 The figure shows the water contact angle of the perovskite film obtained by adjusting the concentration of PMMA in ethyl acetate in Example 1 of the present invention. The results show that the water contact angle is the largest when the PMMA content is 1 mg / mL, indicating that the film has the highest stability.

[0060] Table 1 shows the performance parameters of the wide-bandgap perovskite solar cell of Example 1 of the present invention under different irradiance levels, such as indoor low-light LEDs.

[0061]

[0062] Table 2 shows the indoor low-light performance parameters of wide-bandgap perovskite solar cells of Comparative Examples 1, 2, and 1 of this invention.

[0063]

[0064]

[0065] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an indoor low-light solar cell, characterized in that, Includes the following steps: Preparation of PMMA-Al2O3 solution: Dissolve Al2O3 dispersion in isopropanol solvent to prepare solution A; dissolve PMMA in isopropanol solvent to prepare solution B; mix solution A and solution B to obtain PMMA-Al2O3 solution; Preparation of perovskite precursor solution: according to Cs x FA y MA 1-x-y PbI z Br 3-z Weigh CsI, FAI, PbI2, MABr, and PbBr2, where 0.04≤x≤0.06, 0.6≤y≤0.7, and 2≤z≤2.

5. Dissolve CsI in DMSO to prepare a CsI solution. Dissolve FAI and PbI2 in a mixed solvent DMF / DMSO to prepare a FAPbI3 solution. Dissolve MABr and PbBr2 in a mixed solvent DMF / DMSO to prepare a MAPbBr3 solution. Mix the CsI solution, FAPbI3 solution, and MAPbBr3 solution to construct a wide-bandgap perovskite precursor solution. Fabrication of solar cells: A hole transport layer was prepared on a transparent substrate; an Al2O3-PMMA thin film was prepared by spin-coating an Al2O3-PMMA solution onto the hole transport layer; the film was transferred to a dry glove box, and a wide-bandgap perovskite mixed solution was spin-coated onto the Al2O3-PMMA thin film; 5-10 seconds before the end of the spin-coating process, an EA-PMMA mixed solution was dropped onto the rotating wide-bandgap perovskite thin film; the perovskite thin film was then annealed at 95-100℃ for 15-20 min to crystallize the film and obtain Cs. x FA y MA 1-x-y PbI z Br 3-z -PMMA film; In Cs x FA y MA 1-x-y PbI z Br 3-z A passivation layer, an electron transport layer, and a back electrode are sequentially fabricated on a PMMA thin film.

2. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The concentration of the CsI solution is 1.3–1.5 M; the concentration of the FAPbI3 solution is 1.3–1.5 M; and the concentration of the MAPbBr3 solution is 1.3–1.5 M.

3. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The process of fabricating a hole transport layer on a transparent substrate specifically involves: After cleaning and ozone treatment of the ITO glass substrate, NiO was prepared on the ITO glass substrate at room temperature using radio frequency magnetron sputtering. x Layers, to obtain ITO / NiO x Substrate; then PTAA solution was spin-coated onto ITO / NiO. x Hole transport layer NiO fabricated on substrate x / PTAA film.

4. The method for preparing an indoor low-light solar cell according to claim 3, characterized in that, The PTAA solution is spin-coated onto ITO / NiO x Preparation of ITO / NiO on substrate x / PTAA film, specifically: spin-coating a PTAA solution onto an ITO / NiO film. x On an ITO glass substrate, a hole transport layer NiO is obtained by heating to 110-120℃. x / PTAA film.

5. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The preparation of Al2O3-PMMA thin film by spin-coating Al2O3-PMMA solution onto hole transport layer specifically involves: spin-coating Al2O3-PMMA solution onto hole transport layer and heating to 110-120℃ to obtain Al2O3-PMMA thin film.

6. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The preparation of the passivation layer specifically involves: A PEAI solution with isopropanol as solvent was deposited on a wide-bandgap perovskite film at a spin speed of 3900-4100 rpm for 27-31 s, followed by annealing at 95-100℃ for 8-11 min. The concentration of the PEAI solution was 0.8-1.2 mg / mL.

7. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The electron transport layer is prepared as follows: a 30-40 nm thick C60 film is deposited in a metal thermal evaporation apparatus, and the sample after C60 film deposition is placed in an atomic layer deposition apparatus to prepare a SnO2 film. The deposition cycle is 180-200 cycles and the deposition time is 15-20 min.

8. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The back electrode is prepared as follows: Ag with a thickness of 200-250 nm is thermally evaporated.

9. The method for preparing an indoor low-light solar cell according to claim 1, characterized in that, The concentration of PMMA in the EA-PMMA mixed solution is 0.2-1 mg / mL.

10. An indoor low-light solar cell, characterized in that, It is prepared by the method for preparing an indoor low-light solar cell according to any one of claims 1 to 9.

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