Indoor weak light solar cell and preparation method thereof

Abstract

The invention 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; the hole transport layer is coated with the mixed Al2O3-PMMA solution in a spinning mode, and an Al2O3-PMMA thin film is prepared; the preparation method comprises the following steps: taking an EA-PMMA mixed solution as a substrate, transferring to a dry glove box, spin-coating a broadband gap perovskite mixed solution, dripping the EA-PMMA mixed solution onto a rotating broadband gap perovskite thin film 5-10 seconds before the process of spin-coating the broadband gap perovskite mixed solution is finished, annealing for 15-20 minutes at 95-100 DEG C, crystallizing the perovskite thin film, and sequentially preparing a passivation layer, an electron transport layer and a back electrode. According to the invention, effective ohmic contact in a photovoltaic device can be effectively improved, the component uniformity of a wide-band-gap perovskite thin film with high bromine content is improved, the non-ohmic leakage current loss is reduced, and the weak light performance of a wide-band-gap perovskite photovoltaic cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly relates to an indoor low-light solar cell and a preparation method thereof. Background Art

[0002] Although crystalline silicon cells dominate the photovoltaic market with a mature industrial chain, high photoelectric conversion efficiency, and low cost, their low transparency and poor low-light effect cannot meet the requirements of multiple application scenarios such as wide light intensity efficient long-term power generation and building integrated photovoltaics (BIPV). The adjustable bandgap of perovskite materials and the flexible regulation of their spectral absorption range and intensity can be applied to photovoltaic collection systems with a wide light intensity range, especially for the design of smart windows, building integration for indoor / outdoor dual applications, and integrated Internet of Things (IoT) systems, etc., which is of great significance.

[0003] The adjustable bandgap range of multi-component perovskite thin films enables their photovoltaic devices to have efficient long-term power generation performance under different light intensities. The open-circuit voltage and fill factor of perovskite photovoltaic devices under low light depend on the non-Ohmic leakage and Ohmic leakage inside the devices respectively. How to effectively improve the effective Ohmic contact inside the photovoltaic device, reduce the series resistance while increasing the parallel resistance, is the key to improving the low-light performance of wide-bandgap perovskite photovoltaic cells. In addition, during the preparation process of wide-bandgap perovskite solar cells, wide-bandgap perovskite thin films with a high bromine content (molar content exceeding 20%) are prone to halogen phase separation, resulting in large losses of open-circuit voltage and fill factor of photovoltaic devices 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 the present invention is to provide a preparation method of an indoor low-light solar cell, which can effectively improve the effective Ohmic contact inside the photovoltaic device, improve the compositional uniformity of wide-bandgap perovskite thin films with a high bromine content, reduce non-Ohmic leakage current losses, and improve the low-light performance of wide-bandgap perovskite photovoltaic cells.

[0005] Another purpose of the present invention is to provide an indoor low-light solar cell prepared by the above preparation method.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] The present invention provides a preparation method of an indoor low-light solar cell, comprising the following steps:

[0008] Prepare PMMA - Al 2 O 3 Solution: Dissolve Al 2 O 3The dispersion was dissolved in isopropanol solvent to prepare Solution A; PMMA was dissolved in isopropanol solvent to prepare Solution B; Solution A and Solution B were mixed to obtain a PMMA - Al 2 O 3 solution;

[0009] Prepare a perovskite precursor solution: According to Cs x FA y MA 1-x-y PbI z Br 3-z Weigh CsI, FAI, PbI 2 , MABr and PbBr 2 , where 0.04 ≤ x ≤ 0.06, 0.6 ≤ y ≤ 0.7, 2 ≤ z ≤ 2.5; Dissolve CsI in DMSO solvent to prepare a CsI solution, and dissolve FAI and PbI 2 in a mixed solvent of DMF / DMSO to prepare a FAPbI 3 solution; Dissolve MABr and PbBr 2 in a mixed solvent of DMF / DMSO to prepare a MAPbBr 3 solution; Mix the CsI solution, FAPbI 3 solution, and MAPbBr 3 solution to construct a wide - bandgap perovskite precursor solution;

[0010] Prepare a solar cell:

[0011] Prepare a hole - transporting layer on a transparent substrate; Spin - coat the Al 2 O 3 -PMMA solution on the hole - transporting layer to prepare an Al 2 O 3 -PMMA thin film; Transfer it to a dry glove box, and spin - coat a wide - bandgap perovskite mixed solution on the Al 2 O 3 -PMMA thin film. Five to ten seconds before the end of the procedure of spin - coating the wide - bandgap perovskite mixed solution, drop the EA - PMMA mixed solution onto the rotating wide - bandgap perovskite thin film, and anneal it at 95 - 100 °C for 15 - 20 min to crystallize the perovskite thin film, obtaining a Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA thin film;

[0012] On the 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 the PMMA film.

[0013] Preferably, the concentration of the CsI solution is 1.3 - 1.5 M; the concentration of the FAPbI 3 solution is 1.3 - 1.5 M; the concentration of the MAPbBr 3 solution is 1.3 - 1.5 M.

[0014] Preferably, the preparation of the hole transport layer on the transparent substrate is specifically as follows:

[0015] After cleaning and ozone treatment of the ITO glass substrate, an NiO layer is fabricated on the ITO glass substrate at room temperature by radio frequency magnetron sputtering to obtain an ITO / NiO x substrate; subsequently, the PTAA solution is spin-coated on the ITO / NiO x substrate to fabricate the hole transport layer NiO x / PTAA film. x / PTAA film.

[0016] Preferably, the spin-coating of the PTAA solution on the ITO / NiO x substrate to fabricate the ITO / NiO x / PTAA film is specifically as follows:

[0017] The PTAA solution is spin-coated on the ITO / NiO x substrate, and after heating at 110 - 120 °C, a hole transport layer NiO x / PTAA film is obtained on the ITO glass substrate.

[0018] Preferably, the spin-coating of the Al 2 O 3 -PMMA solution on the hole transport layer to fabricate the Al 2 O 3 -PMMA film is specifically as follows: The Al 2 O 3 -PMMA solution is spin-coated on the hole transport layer, and after heating at 110 - 120 °C, an Al 2 O 3 -PMMA film is obtained.

[0019] Preferably, the preparation of the passivation layer is specifically as follows:

[0020] A PEAI solution with isopropanol as the solvent is deposited on the wide-bandgap perovskite film at a rotation speed of 3900 - 4100 rpm for a spin-coating time of 27 - 31 s, and then annealed on a hot plate at 95 - 100 °C for 8 - 11 min; the concentration of the PEAI solution is 0.8 - 1.2 mg / mL.

[0021] Preferably, the electron transport layer is prepared as follows: deposit C60 with a thickness of 30 - 40 nm in a metal thermal evaporation device, and put the sample with the deposited C60 film into an atomic layer deposition device to prepare SnO 2 film, the deposition times are 180 - 200 cycles, and the deposition time is 15 - 20 min.

[0022] Preferably, the back electrode is prepared as follows: thermally evaporate Ag with 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, PMMA-Al 2 O 3 solution is prepared as follows: take 1 - 1.2 mL of Al 2 O 3 dispersion and dissolve it in 50 - 52 mL of isopropanol solvent to prepare solution A; take 0.05 - 0.07 mg of PMMA and dissolve it in 1 - 1.2 mL of isopropanol solvent to prepare solution B; take 1 - 1.2 mL of solution B and mix it in 5 - 5.2 mL of solution A to obtain PMMA-Al 2 O 3 solution.

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

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

[0027] ITO / NiO x / PTAA / Al 2 O 3 -PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA / PEAI / C 60 / SnO 2 / Ag.

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

[0029] (1) For the indoor low-light solar cell of the present invention, by using PMMA-Al 2 O 3A composite interface layer is inserted between the interface of the wide-bandgap perovskite and the hole transport layer. Meanwhile, a wide-bandgap perovskite-PMMA bulk heterojunction thin film with a specific composition of the present invention is used as the light absorption layer to improve the effective ohmic contact inside the photovoltaic device, reduce the series resistance while increasing the shunt resistance, and improve the low-light performance of the wide-bandgap perovskite photovoltaic cell. For example, in the embodiment of the present invention, for the perovskite photovoltaic cell with a bandgap, under the conditions of 1,000 lux and 3,000 K, the output power of the cell reaches 132.02 μW / cm -2 , and the low-light efficiency reaches 43.91%. Its V oc , FF and J sc reach 1.07 V, 83.62% and 148.15 μA / cm 2 respectively; under the conditions of 600 lux and 3,000 K, the output power of the cell reaches 80.231 μW / cm -2 , and the low-light efficiency reaches 44.28%. Its V oc , FF and J sc reach 1.04 V, 82.83% and 93.36 μA / cm 2 .

[0030] (2) For the indoor low-light solar cell of the present invention, by simultaneously using the PMMA-Al 2 O 3 composite interface layer of the present invention and using the wide-bandgap perovskite-PMMA bulk heterojunction thin film of the present invention as the light absorption layer, the component distribution in the thin film becomes more uniform, thereby reducing the non-ohmic leakage current loss. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2 FIG. is a J-V curve diagram of the indoor low-light solar cell according to Embodiment 1 of the present invention under different irradiances of indoor low-light LEDs.

[0033] Figure 3 FIG. is a J-V curve diagram of the solar cells according to Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention under low-light conditions (1,000 lux, 3,000 K conditions) of indoor low-light L.

[0034] Figure 4 FIG. shows the series resistance (a) and shunt resistance (b) of the devices of Comparative Example 1, Comparative Example 2, and Embodiment 1 of the present invention.

[0035] Figure 5 FIG. is a fluorescence scanning comparison diagram of the perovskite films of Comparative Example 1, Comparative Example 2, and Embodiment 1 of the present invention.

[0036] Figure 6 Comparative diagram of fluorescence spectra of perovskite films for Comparative Example 1, Comparative Example 2 and Example 1 of the present invention.

[0037] Figure 7 Diagram showing the crystallization of perovskite thin films with different contents of PMMA over time.

[0038] Figure 8 Water contact angles of perovskite thin films with different contents of PMMA, where (a) to (d) are the same concentrations of PMMA in ethyl acetate at 0 mg / mL, 0.2 mg / mL, 0.5 mg / mL, and 1 mg / mL, respectively. Detailed implementation manners

[0039] The present invention will be further described in detail below in conjunction with examples, but the implementation manners of the present invention are not limited thereto.

[0040] Example 1

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

[0042] The preparation method of the indoor low-light solar cell of this example includes the following steps:

[0043] Prepare a PMMA-Al 2 O 3 solution: Take 1 mL of Al 2 O 3 dispersion (particle size is 30 nm, dissolved in isopropanol solvent, concentration is 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 in 5 mL of solution A to obtain a PMMA-Al 2 O 3 solution.

[0044] Prepare a perovskite precursor solution: According to Cs x FA y MA 1-x-yPbI z Br 3-z Weigh CsI, FAI, PbI 2 , MABr and PbBr 2 , where, in Example x = 0.05, y = 0.70, z = 2.15; Dissolve CsI in DMSO solvent to prepare CsI solution, and dissolve FAI and PbI 2 in the mixed solvent DMF / DMSO to prepare FAPbI 3 solution; Dissolve MABr and PbBr 2 in the mixed solvent DMF / DMSO to prepare MAPbBr 3 solution; Mix the CsI solution, FAPbI 3 solution, and MAPbBr 3 solution to construct a wide-bandgap perovskite precursor solution;

[0045] Preparation process of solar cell: First, the ITO glass substrate is ultrasonically cleaned with detergent, deionized water, and IPA in sequence for 10 minutes, dried with N 2 stream and then treated with ozone for minutes, and start to prepare the NiO x layer on the NiO target by radio frequency magnetron sputtering at room temperature. Subsequently, spin-coat the PTAA solution on the ITO / NiO x substrate at a speed of 4500 rpm for 28 s, and heat it on a hot stage at 115 °C for 18 min to obtain the ITO / NiO x / PTAA thin film. Then, spin-coat the prepared Al 2 O 3 -PMMA solution on the ITO / NiO x / PTAA thin film substrate at a speed of 4000 - 4500 rpm for 28 s, and heat it on a hot stage at 115 °C for 20 minutes to obtain the ITO / NiO x / PTAA / Al 2 O 3 -PMMA thin film. Transfer the prepared ITO / NiO x / PTAA / Al 2 O 3 -PMMA to a dry and airtight glove box, then spin-coat the wide-bandgap perovskite mixed solution. 10 seconds before the end of the program, drop 220 μL of the EA-PMMA mixed solution (0.5 mg / mL) onto the rotating wide-bandgap perovskite thin film, and then anneal it at 98 - 100 °C for 18 - 20 min for perovskite thin film crystallization to obtain ITO / NiO x / PTAA / Al 2 O 3 -PMMA / Cs x FA y MA1-x-y PbI z Br 3-z -PMMA thin film. Then, a 1 mg / mL PEAI solution with isopropanol as the solvent was deposited on the wide-bandgap perovskite thin film at a rotation speed of 4000 rpm for 30 s of spin coating, and then annealed on a hot plate at 100 °C for 10 min. Then the sample was transferred to a metal thermal evaporation equipment to deposit 35 nm thick C60 as the electron transport layer, and the sample with the C60 thin film deposited was put into an atomic layer deposition equipment to prepare SnO 2 thin film, the deposition times were 190 cycles and the deposition time was 18 minutes, and then 220 nm thick Ag was thermally evaporated. The finally prepared perovskite solar cell structure was: ITO / NiO x / PTAA / Al 2 O 3 -PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z -PMMA / PEAI / C 60 / SnO 2 / Ag.

[0046] Comparative Example 1

[0047] The perovskite solar cell structure prepared in this comparative example was: ITO / NiO x / PTAA / Al 2 O 3 / Cs x FA y MA 1-x- y PbI z Br 3-z / PEAI / C 60 / SnO 2 / Ag, where the preparation of the Al 2 O 3 solution was as follows: 1 - 1.2 mL of Al 2 O 3 dispersion was dissolved in 50 - 52 mL of isopropanol solvent to prepare an Al 2 O 3 solution; during the preparation of the wide-bandgap perovskite thin film, the EA-PMMA mixed solution was not used for treatment.

[0048] Except for the above differences, other features of this comparative example were the same as those of Example 1.

[0049] Comparative Example 2

[0050] The perovskite solar cell structure prepared in this comparative example was: ITO / NiOx / PTAA / Al 2 O 3 -PMMA / Cs x FA y MA 1-x-y PbI z Br 3-z / PEAI / C 60 / SnO 2 / Ag. During the preparation of the wide-bandgap perovskite thin film, the EA-PMMA mixed solution is not used for treatment.

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

[0052] The low-light performance tests are carried out on the perovskite solar cells of Example 1, Comparative Example 1, and Comparative Example 2.

[0053] Figure 2 And Table 1 shows the performance of the indoor low-light solar cell of Example 1 of the present invention under different irradiances of indoor low-light LEDs. The results show that: the indoor low-light solar cell of Example 1 has good low-light performance.

[0054] Figure 3 In Table 2, the performance comparison of the solar cells of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention under low-light conditions (1,000 lux, 3,000 K condition) is shown. It can be seen that, compared with Comparative Example 1, in Comparative Example 2, during the preparation of the wide-bandgap perovskite thin film, the EA-PMMA mixed solution is used for treatment, which has no effect on the open-circuit voltage. However, in Example 1, by combining the use of the wide-bandgap perovskite-PMMA bulk heterojunction thin film and the PMMA-Al 2 O 3 composite interface layer, the open-circuit voltage is greatly improved. The above results show that: only using the wide-bandgap perovskite-PMMA bulk heterojunction thin film cannot improve the open-circuit voltage, and it is necessary to combine the wide-bandgap perovskite-PMMA bulk heterojunction thin film and the PMMA-Al 2 O 3 composite interface layer to achieve it. At the same time, through comparison, it can be seen that in the forward scan test, the solar cells of Example 1 and Comparative Example 2 are equivalent to Comparative Example 1, and the FF and PCE parameters are improved to varying degrees; while in the reverse scan test, the FF and PCE of Comparative Example 2 are slightly decreased compared with Comparative Example 1, while Example 1 has a significant increase compared with Comparative Example 1.

[0055] Figure 4 In (a) and (b), the series resistance and parallel resistance of the solar cells of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention are shown respectively. The results show that Example 1 has a low series resistance (R s= 1.37 Ohm cm -2 ), while the series resistances of Comparative Example 1 and Comparative Example 2 are relatively high, which are respectively: 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 Example 1 and Comparative Example 2 have low parallel resistances: R sh = 840 Ohm cm -2 and R sh = 1113 Ohm cm -2 ; The results show that by combining the use of the wide-bandgap perovskite-PMMA bulk heterojunction film and the PMMA-Al 2 O 3 composite interface layer, the ohmic and non-ohmic leakage currents are lower, the minimum series resistance, the maximum parallel resistance, the non-ohmic and ohmic leakage losses are the smallest, and the low-light performance is the best.

[0056] Figure 5 (a), (b), and (c) in respectively show the fluorescence scanning comparison pictures of the perovskite films of Comparative Example 1, Comparative Example 2, and Example 1 of the present invention. The results show that by combining the use of the wide-bandgap perovskite-PMMA bulk heterojunction film and the PMMA-Al 2 O 3 composite interface layer, the film has low defect states, and the wide-bandgap perovskite film has a relatively high component uniformity distribution.

[0057] Figure 6 shows the fluorescence spectra of the perovskite films of Comparative Example 1, Comparative Example 2, and Example 1 of the present invention. The results show that by combining the use of the wide-bandgap perovskite-PMMA bulk heterojunction film and the PMMA-Al 2 O 3 composite interface layer, the film has low defect states, which is beneficial to charge separation and transport.

[0058] Figure 7 shows the pictures of the crystallization of the perovskite film over time obtained by adjusting the concentration of PMMA in ethyl acetate in Example 1 of the present invention. Figure 7 It shows that the crystallization time of the wide-bandgap perovskite film containing PMMA in Example 1 is relatively long, which is beneficial to the growth of film crystals.

[0059] Figure 8 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 when the PMMA content is 1 mg / mL, the water contact angle is the largest, indicating the highest film stability.

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

[0061]

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

[0063]

[0064]

[0065] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an indoor weak light solar cell, characterized in that: The following steps are involved: Prepare 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: Press Cs x FA y MA 1-x-y PbI z Br 3-z Weigh CsI, FAI, PbI2, MABr and PbBr2, wherein 0.04≤x≤0.06, 0.6≤y≤0.7, and 2≤z≤2.5; dissolve CsI in DMSO solvent to prepare CsI solution, dissolve FAI and PbI2 in a mixed solvent DMF / DMSO to prepare FAPbI3 solution; dissolve MABr and PbBr2 in a mixed solvent DMF / DMSO to prepare MAPbBr3 solution; mix the CsI solution, the FAPbI3 solution, and the MAPbBr3 solution to construct a wide bandgap perovskite precursor solution; Preparation of solar cells: A hole transport layer is prepared on a transparent substrate; an Al2O3-PMMA solution is spin-coated on the hole transport layer to prepare an Al2O3-PMMA film; the film is transferred to a dry air glove box, a wide bandgap perovskite mixed solution is spin-coated on the Al2O3-PMMA film, 5-10 seconds before the end of the spin-coating of the wide bandgap perovskite mixed solution, an EA-PMMA mixed solution is dropped onto the rotating wide bandgap perovskite film, and the perovskite film is crystallized by annealing at 95-100°C for 15-20 minutes to 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 -The passivation layer, electron transport layer and back electrode are prepared in sequence on the PMMA film.

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

3. The method for preparing an indoor weak light solar cell according to claim 1, characterized in that: The method of preparing a hole transport layer on a transparent substrate comprises: After the ITO glass substrate was cleaned and treated with ozone, NiO was prepared on the ITO glass substrate by radio frequency magnetron sputtering at room temperature. x layer, and obtain ITO / NiO x Substrate; PTAA solution was then spin coated on ITO / NiO x Preparation of NiO hole transport layer on substrate x / PTAA film.

4. The method for preparing an indoor weak light solar cell according to claim 3, characterized in that: The PTAA solution was spin-coated on the ITO / NiO x Preparation of ITO / NiO on substrate x / PTAA film, specifically: spin-coat the PTAA solution on ITO / NiO x On the substrate, after heating at 110-120°C, a hole transport layer NiO is obtained on the ITO glass substrate. x / PTAA film.

5. The method for preparing an indoor weak light solar cell according to claim 1, characterized in that: The Al2O3-PMMA film is prepared by spin coating the Al2O3-PMMA solution on the hole transport layer, specifically: the Al2O3-PMMA solution is spin coated on the hole transport layer, and heated to 110-120° C. to obtain the Al2O3-PMMA film.

6. The method for preparing an indoor weak light solar cell according to claim 1, characterized in that: The preparation of the passivation layer specifically comprises: A PEAI solution with isopropanol as solvent is deposited on the wide bandgap perovskite film at a rotation speed of 3900-4100 rpm and a spin coating time of 27-31 seconds, and then annealed on a 95-100° C. hot stage for 8-11 minutes; the concentration of the PEAI solution is 0.8-1.2 mg / mL.

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

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

9. The method for preparing an indoor weak-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. Indoor weak light solar cell, characterized in that: The indoor weak-light solar cell is prepared by the preparation method of any one of claims 1 to 9.

Images