A method for preparing a perovskite solar cell

Abstract

The application discloses a preparation method of a perovskite solar cell, and comprises the following steps: step one) preparing a SnO2 layer on a transparent conductive glass; step two) coating an inorganic layer on the SnO2 layer after heating and stirring a solution containing PbI2, PbBr2, CsI and NpMAI at 60-80 DEG C for 11-13 hours and annealing at 65-75 DEG C for 8-12 seconds; step three) coating an organic layer on the inorganic layer after heating and stirring a solution containing FAI, MAI and MACl at 60-80 DEG C for 20-40 minutes, and annealing at air humidity of 40-50 %, temperature of 170-180 DEG C for 1-5 minutes, and then annealing at air humidity of 40-50 %, temperature of 140-160 DEG C for 5-15 minutes; and step four) sequentially preparing a passivation layer, a hole transport layer and an electrode layer on the organic layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a preparation method of a perovskite solar cell. BACKGROUND

[0002] Organic-inorganic halide perovskite materials are considered to be the most promising new photovoltaic materials due to their excellent optoelectronic properties, long carrier diffusion length, strong light absorption and low processing cost. After decades of development, the power conversion efficiency of single-junction perovskite solar cells has rapidly increased from 3.8% to 26.7%, close to the Shockley-Queisser limit. In order to further improve the photon absorption efficiency of solar cells, the construction of a stacked cell composed of a wide-bandgap perovskite top cell and a c-Si solar cell has become a research hotspot in the academic and industrial communities.

[0003] Due to its special charge transport mechanism, perovskite cells are prone to performance hysteresis, that is, there is a large difference in performance when applying forward voltage and reverse voltage. The above shortcomings limit the commercialization and practicality of perovskite cells. The existing continuous annealing process causes non-uniformity in the crystallization process due to the uncontrollability of the perovskite crystallization process, resulting in differences in grain growth speed at different positions in the thin film, thus causing problems of loose contact between grain boundaries and large voids. SUMMARY

[0004] The present application provides a preparation method of a perovskite solar cell to reduce the performance hysteresis problem of the perovskite solar cell, which can be implemented by the following technical scheme:

[0005] A preparation method of a perovskite solar cell, comprising the following steps:

[0006] Step 1) preparing a SnO2 layer on a transparent conductive glass;

[0007] Step 2) heating and stirring a solution containing PbI2, PbBr2, CsI and NpMAI at 60-80℃ for 11-13h, then coating it on the SnO2 layer, and annealing at 65-75℃ for 8-12s to obtain an inorganic layer;

[0008] Step 3) heating and stirring a solution containing FAI, MAI and MACl at 60-80℃ for 20-40min, then coating it on the inorganic layer, and annealing at an air humidity of 40%-50% and a temperature of 170-180℃ for 1-5min, and then annealing at an air humidity of 40%-50% and a temperature of 140-160℃ for 5-15min to obtain an organic layer;

[0009] Step four) sequentially preparing a passivation layer, a hole transport layer and an electrode layer on the organic layer.

[0010] Optionally, in the step one), the solution containing SnO2 is spin-coated on the transparent conductive glass at a spin speed of 2500-3500 rpm for 25-35 s, and then annealed at 140-160℃ for 20-40 min, and then cooled to form the SnO2 layer.

[0011] Optionally, in the step one), the transparent conductive glass with the spin-coated SnO2 layer is placed in an ultraviolet-ozone box for ultraviolet-ozone treatment for 10 min.

[0012] Optionally, in the step two), the mass ratio of PbI2:PbBr2:CsI is 0.7-0.75:0.3-0.25:0.001-0.003, and the mass of NpMAI is 4-6‰ of the mass of PbI2.

[0013] Optionally, in the step two), the solution containing PbI2, PbBr2, CsI and NpMAI is heated and stirred at 60-80℃ for 11-13 h, and then spin-coated on the SnO2 layer at a spin speed of 1800-2000 rpm for 25-35 s.

[0014] Optionally, in the step three), the mass ratio of FAI:MAI:MACl is 75-78:15-12:16-20.

[0015] Optionally, the solution containing FAI, MAI and MACl is heated and stirred at 60-80℃ for 25-35 min, and then spin-coated on the inorganic layer at a spin speed of 2000-2500 rpm for 35-45 s.

[0016] Optionally, in the step three), annealing is performed at an air humidity of 40%-50% and a temperature of 170-180℃ for 3 min, and then annealing is performed at an air humidity of 40%-50% and a temperature of 150℃ for 10-15 min.

[0017] Optionally, the passivation layer is at least one of BABr, BAI, NpMABr, NpMAI, PEABr, PEAI and BnBr.

[0018] The hole transport layer is at least one of Spiro-OMeTAD, PTAA, NiOx and MoOx.

[0019] The electrode layer is Ag 、 at least one of Cu and Au.

[0020] The present invention also proposes a perovskite solar cell prepared by the above-mentioned method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The preparation method in this invention employs a stepwise annealing process to anneal the organic layer of perovskite solar cells, which can effectively reduce the hysteresis problem of perovskite solar cells. Furthermore, this invention proposes optimal annealing parameters for the perovskite material used, contributing to the production of high-performance perovskite solar cells. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0024] The terms "comprising," "including," "having," "containing," etc., used in this document are all open-ended terms, meaning they include but are not limited to. All raw materials used in the various embodiments are commercially available products.

[0025] Example 1

[0026] Step 1) Prepare SnO2 solution, spin-coat SnO2 solution onto ITO transparent conductive glass at 3000 rpm for 30 s, then anneal at 150℃ for 30 min, cool and then treat with ultraviolet ozone for 10 min to form SnO2 layer.

[0027] Step 2) PbI 2、 PbBr 2、 CsI ​​and NpMAI were dissolved in a DMF / DMSO (94 / 6 volume ratio) mixed solution, with PbI2:PbBr2:CsI = 0.73:0.27:0.002 and NpMAI to PbI2 mass ratio of 5‰. The mixture was then reacted with hot stirring at 70℃ for 12 h. The solution was then spin-coated onto a SnO2 layer at 1900 rpm for 30 s, followed by annealing at 70℃ for 10 s and cooling to room temperature to form an inorganic layer.

[0028] Step 3) Dissolve 76.5 mg FAI, 13.5 mg MAI, and 18 mg MACl in 1 ml IPA and heat and stir at 70°C for 30 min. Then spin-coat the solution onto the inorganic layer at 2300 rpm for 40 s, and immediately anneal in air at 170°C for 1 min, and then anneal at 150°C for 5 min. The air humidity during annealing is 40-50%, forming an organic layer.

[0029] Step 4) Dissolve BABr in IPA to a concentration of 4 mg / ml to obtain a BABr solution. Spin-coat the BABr solution onto the organic layer at 4000 rpm for 30 seconds, and anneal at 80°C for 5 minutes.

[0030] Step 5) Preparation of Spiro-OMeTAD hole transport layer

[0031] a. Accurately weigh 260 mg Li-TFSI into a sample vial using an electronic balance, add 1 mL of anhydrous acetonitrile in a glove box, and stir at room temperature for 1 h to dissolve it.

[0032] b. Accurately weigh 80 mg of Spiro-OMeTAD into a sample vial using an electronic balance. Add 1 mL of chlorobenzene to a glove box and stir at room temperature in the dark for 2 hours. Then add 30 μL of t-BP and stir until homogeneous. Next, add 35 μL of Li-TFSI (260 mg / mL) solution for doping. Stir at room temperature for 2 hours to obtain the Spiro-OMeTAD hole transport layer solution. Spin-coat the Spiro-OMeTAD solution at 6000 rpm for 30 seconds, and then transfer it to an air-drying oven for oxidation for approximately 10 hours.

[0033] Step 6) Prepare Ag electrodes on the hole transport layer.

[0034] Example 2

[0035] Compared to Example 1, the annealing process was modified to anneal at 170°C for 1 min, followed by annealing at 150°C for 10 min. Other conditions were the same as in Example 1.

[0036] Example 3

[0037] Compared to Example 1, the annealing process was modified to anneal at 170°C for 1 min, followed by annealing at 150°C for 15 min. Other conditions were the same as in Example 1.

[0038] Example 4

[0039] Compared to Example 1, the annealing process was modified to anneal at 180°C for 3 minutes, followed by annealing at 150°C for 10 minutes. Other conditions were the same as in Example 1.

[0040] Example 5

[0041] Compared to Example 1, the annealing process was modified to anneal at 170°C for 3 minutes, followed by annealing at 150°C for 10 minutes. Other conditions were the same as in Example 1.

[0042] Example 6

[0043] Compared to Example 1, the annealing process was modified to anneal at 170°C for 3 minutes, followed by annealing at 150°C for 15 minutes. Other conditions were the same as in Example 1.

[0044] Example 7

[0045] Compared to Example 1, the annealing process was modified to anneal at 175°C for 5 minutes, followed by annealing at 145°C for 10 minutes. Other conditions were the same as in Example 1.

[0046] Example 8

[0047] Compared to Example 1, the annealing process was modified to anneal at 175°C for 5 minutes, followed by annealing at 155°C for 5 minutes. Other conditions were the same as in Example 1.

[0048] Example 9

[0049] Compared to Example 1, the annealing process was modified to anneal at 180°C for 1 min, followed by annealing at 160°C for 5 min. Other conditions were the same as in Example 1.

[0050] Compared with Example 1, the annealing time in step 3) was adjusted as shown in Table 1.

[0051] Comparative Example 1

[0052] The annealing process in step 3) of Example 1 is modified to anneal at 170°C for 15 minutes.

[0053] Table 1 Performance test results of the embodiments

[0054]

[0055]

[0056] Experimental results show that the hysteresis factor decreases during stepwise annealing. The best results are obtained by annealing at 170–180℃ for 3 min or at 150℃ for 10–15 min.

[0057] Comparative Example 2

[0058] Compared with Example 1, the annealing process in step 3) is modified to first be treated at 150°C for 1 min, and then treated at 170°C for 15 min.

[0059] Comparative Example 3

[0060] Compared with Example 1, the annealing process in step 3) is modified to first be treated at 130°C for 5 minutes, and then treated at 170°C for 15 minutes.

[0061] Table 2 Comparative Performance Test Results

[0062]

[0063]

[0064] As shown in Table 2, annealing at low temperature followed by annealing at high temperature cannot achieve a good effect in reducing hysteresis.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: Step 1) Prepare a SnO2 layer on transparent conductive glass; Step 2) The solution containing PbI2, PbBr2, CsI and NpMAI is heated and stirred at 60~80℃ for 11~13h, then coated on SnO2 layer and annealed at 65~75℃ for 8~12s to obtain inorganic layer. Step 3) After heating and stirring the solution containing FAI, MAI and MACl at 60-80℃ for 20-40 min, coat it onto the inorganic layer and anneal it at 170-180℃ for 1-5 min under conditions of 40%-50% air humidity; then anneal it at 140-160℃ for 5-15 min under conditions of 40%-50% air humidity to obtain the organic layer. Step 4) A passivation layer, a hole transport layer, and an electrode layer are sequentially prepared on the organic layer; In step two), the mass ratio of PbI2:PbBr2:CsI is (0.7~0.75):(0.3~0.25):(0.001~0.003), and the mass of NpMAI is 4~6‰ of the mass of PbI2. In step three), the mass ratio of FAI:MAI:MACl is (75~78):(15~12):(16~20).

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step one), a solution containing SnO2 is spin-coated onto a transparent conductive glass at a spin speed of 2500~3500 rpm for 25~35s. After spin-coating, the glass is annealed at 140~160℃ for 20~40 min. After annealing, the glass is cooled to form a SnO2 layer.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Step one also includes placing a transparent conductive glass coated with a SnO2 layer into an ultraviolet-ozone chamber for ultraviolet ozone treatment for 10 minutes.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step two, the solution containing PbI2, PbBr2, CsI and NpMAI is heated and stirred at 60~80℃ for 11~13h and then spin-coated onto the SnO2 layer. The spin-coating speed is 1800~2000rpm and the spin-coating time is 25~35s.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The solution containing FAI, MAI and MACl was heated and stirred at 60~80℃ for 25~35 min and then spin-coated onto the inorganic layer at a spin speed of 2000~2500 rpm for 35~45 s.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step three), anneal for 3 minutes at an air humidity of 40%-50% and a temperature of 170-180℃; then anneal for 10-15 minutes at an air humidity of 40%-50% and a temperature of 150℃.

7. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The passivation layer is at least one of BABr, BAI, NpMABr, NpMAI, PEABr, PEAI, and BnBr passivation layers; The hole transport layer uses at least one of Spiro-OMeTAD, PTAA, NiOx, and MoOx; The electrode layer is made of at least one of Ag, Cu, and Au.

8. The perovskite solar cell prepared by the method according to any one of claims 1 to 7.

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