Preparation of sericin modification-based perovskite thin film and application of sericin modification-based perovskite thin film in perovskite solar cell

Abstract

The invention discloses preparation of a sericin modification-based perovskite thin film and application of the sericin modification-based perovskite thin film in a perovskite solar cell, and belongs to the field of perovskite solar cells. The sericin is used as an additive to regulate and control the perovskite precursor solution, so that on one hand, the problems of rough surface and many defects of a perovskite layer caused by stress concentration in the growth process of perovskite crystal grains are solved, and on the other hand, the sericin plays a role in deprotonation; and the photoelectric conversion efficiency and the stability of the perovskite solar cell can be obviously improved.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and particularly relates to the preparation of a perovskite thin film modified by sericin and its application in perovskite solar cells. Background Art

[0002] As an important renewable clean energy source, solar energy has great development potential and space. With its advantages of wide distribution, high economic benefits, safety and sustainability, it has quickly become a popular energy source for future economic and social development. As an emerging third-generation thin-film battery, perovskite solar cells have the advantages of low production cost, adjustable bandgap, high theoretical conversion efficiency and stackability. The certified efficiency has reached 27.3%, which can be comparable to commercial crystalline silicon batteries. However, for its commercial application, the photoelectric conversion efficiency and stability are still key issues to be solved urgently.

[0003] As the core part of the perovskite solar cell structure, the perovskite light-absorbing layer's crystallization quality directly affects the photoelectric performance of the final battery. When the battery is exposed to light and humid environments, problems such as the deprotonation of common organic cations in the perovskite thin film, the oxidation of iodide, and the residual of excessive lead iodide may cause the decomposition of the perovskite thin film, an increase in the density of defect states, and an increase in the probability of non-radiative recombination, ultimately causing irreversible damage to the performance and stability of the perovskite battery. Summary of the Invention

[0004] Aiming at the problems existing in the above-mentioned prior art, the present invention provides the preparation of a perovskite thin film modified by sericin and its application in perovskite solar cells. The present invention uses sericin as an additive to regulate the perovskite precursor solution, passivate the perovskite grain boundary defects, and improve the crystallinity of the crystal, so that the perovskite solar cell exhibits excellent photoelectric conversion efficiency and light stability.

[0005] Sericin is a biomass material with certain reducibility, which can inhibit the oxidation of iodide. On the other hand, sericin contains groups such as carboxyl (-COOH) and amino (-NH3), which can passivate the defects of the perovskite thin film and effectively improve the quality and performance of the perovskite thin film. Sericin also has certain elasticity and can control the crystallization process of the perovskite thin film during the annealing process. Under the action of sericin, the grains in the perovskite thin film grow optimally, and the grain boundary defects are effectively reduced. At the same time, as a hydrophilic material, sericin can combine with water to prevent water from damaging the perovskite thin film, thereby improving the stability of the perovskite solar cell.

[0006] The preparation method of the perovskite film modified by sericin protein is to add sericin protein as an additive to the perovskite precursor solution, and prepare the perovskite film material by the anti-solvent method.

[0007] Prepare the perovskite precursor solution according to the elemental composition of the perovskite film material. The perovskite film material is ABX3, where A is FA + , MA + , Cs + Any one or more of them, B is Pb 2+ , and X is I — , Cl — , Br — Any one or more of them.

[0008] Furthermore, the precursor solution contains lead iodide (PbI2), methylammonium iodide (MAI), formamidinium hydroiodide (FAI), cesium iodide (CsI), methylammonium chloride (MACl), but is not limited to the materials listed above. The concentration range of the precursor solution is 1.2 - 2.0 mol / L.

[0009] Specifically, it includes the following steps:

[0010] Add the perovskite precursor to the mixed solvent, add sericin protein, and obtain a mixed precursor solution after uniform dispersion; take the mixed precursor solution and spin-coat it by the anti-solvent method, and add the anti-solvent 15 s before the end of spin-coating. After the spin-coating is completed, perform annealing treatment to obtain the perovskite film material.

[0011] The mixed solvent is composed of a compound of DMF and DMSO, and the volume ratio of the two is 4:1.

[0012] In the mixed precursor solution, the concentration of sericin protein is 0.5 - 2.0 mg / mL.

[0013] Furthermore, the specific spin-coating parameters of the anti-solvent method are as follows: First, increase the rotation speed to 1000 rpm at an acceleration of 500 rpm / s to assist the spreading of the precursor solution, and the spin-coating time is 10 s. Then immediately increase the rotation speed to 5000 rpm at 1000 rpm / s, and the spin-coating time is 35 s.

[0014] Furthermore, the anti-solvent is chlorobenzene (CB), diethyl ether (Et2OH), ethyl acetate (EA) or anisole (C7H8O), but is not limited to the anti-solvents listed above.

[0015] Furthermore, the annealing temperature is 120 °C and the time is 10 min.

[0016] The application of the perovskite film modified by sericin protein in constructing perovskite solar cells of the present invention.

[0017] Specifically, the perovskite film modified based on sericin is used as the perovskite light-absorbing layer. The thickness range of the perovskite light-absorbing layer is 500 - 700 nm.

[0018] The reverse structure (p-i-n type) of the perovskite solar cell is sequentially arranged from bottom to top as a transparent conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode; the forward structure (n-i-p type) is sequentially arranged from bottom to top as a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer.

[0019] The perovskite solar cell is of p-i-n type, and its structure from top to bottom is sequentially a transparent conductive substrate, a p-type hole transport layer, a perovskite light-absorbing layer, an n-type electron transport layer, and a metal electrode.

[0020] Specifically, in the p-i-n structure:

[0021] The transparent conductive substrate is indium tin oxide (ITO), fluorine-doped indium tin oxide (FTO), but is not limited to the above-listed transparent conductive substrates.

[0022] The n-type electron transport layer is made of one or more n-type semiconductor materials such as tin oxide (SnO2), titanium oxide (TiO2), zinc oxide (ZnO), C60, [6,6]-phenyl C61 butyric acid methyl ester (PC 61 BM), etc., but is not limited to the above-listed n-type semiconductor materials.

[0023] The perovskite light-absorbing layer is ABX3, where A is FA + , MA + , Cs + Any one or several of them, B is Pb 2+ , X is I ﹣ , Cl ﹣ , Br ﹣ Any one or several of them.

[0024] The p-type hole transport layer can be selected from nickel oxide (NiO x), molybdenum oxide (MoO3), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), self-assembled monolayer (SAM), etc., or one or more p-type semiconductor materials prepared therefrom, but not limited to the p-type semiconductor materials listed above. Among them, SAM is any one or several of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [4-(9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), but not limited to those listed above.

[0025] The metal electrode is gold (Au), silver (Ag), copper (Cu), etc., but not limited to the metal electrodes listed above.

[0026] Alternatively, the perovskite solar cell is of the n-i-p type, and sequentially includes a transparent conductive substrate, an n-type electron transport layer, a perovskite thin film, a p-type hole transport layer, and a metal electrode from bottom to top.

[0027] Specifically, in the n-i-p structure:

[0028] The transparent conductive substrate is indium tin oxide (ITO), fluorine-doped indium tin oxide (FTO), but not limited to the transparent conductive substrates listed above.

[0029] The p-type hole transport layer can be prepared from one or more p-type semiconductor materials such as nickel oxide (NiO), molybdenum oxide (MoO3), cuprous oxide (Cu2O), copper iodide (CuI), copper phthalocyanine (CuPc), copper thiocyanate (CuSCN), etc., but not limited to the p-type semiconductor materials listed above.

[0030] The perovskite light-absorbing layer is ABX3, where A is FA + , MA + , Cs + any one or several of them, B is Pb 2+ , X is I ﹣ , Cl ﹣ , Br ﹣ any one or several of them.

[0031] The n-type electron transport layer can be selected from titanium oxide (TiO2), tin oxide (SnO2), zinc oxide (ZnO), fullerene (C 60), one or more n-type semiconductor materials such as graphene, fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), etc., but not limited to the n-type semiconductor materials listed above.

[0032] The metal electrode is gold (Au), silver (Ag), copper (Cu), etc., but not limited to the metal electrodes listed above.

[0033] The object of the present invention is to provide a preparation method of the above perovskite solar cell. Taking the preparation process of the p-i-n type perovskite solar cell as an example, the preparation process includes the following steps:

[0034] Step 1: Put the conductive glass substrate into detergent, deionized water, acetone, and absolute ethanol in sequence for ultrasonic treatment for 30 min, then put it into an oven at 80 °C for drying, and then place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0035] Step 2: Prepare the hole transport layer by spin coating. The hole transport layer is composed of NiO x and SAM. First, prepare the NiO x solution. Place the transparent conductive substrate after ozone treatment on a spin coater, drop 100 μl each time, and rotate at a speed of 3000 rpm and an acceleration of 3000 rpm / s for 30 s to ensure the formation of a dense and suitable thickness of NiO x layer. After spin coating, anneal on a heating table at 100-120 °C for 15 min to finally obtain the NiO x layer with a thickness of about 20 nm. Deposit a SAM layer on the NiO x layer. Dissolve 2 mg of Me-4PACz in 4 mL of absolute ethanol to obtain the SAM layer precursor solution, and then take 100 µL of the solution and rotate at a speed of 3000 rpm and an acceleration of 3000 rpm / s for 30 s. After spin coating, anneal on a hot plate at 100 °C for 10 min.

[0036] Step 3: Deposit a perovskite thin film on the basis of the previous step. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, and 19.5 mg of CsI in 1 mL of a mixed solvent (DMF: DMSO = 4:1), and add 0-2.0 mg of sericin to the perovskite precursor solution. Then take 120 µL of the solution to prepare the thin film by the anti-solvent method, and add 200 µL of chlorobenzene (CB) as the anti-solvent 15 s before the end of the second spin coating. After spin coating, anneal on a hot plate at 120 °C for 10 min, and the thickness of the thin film is about 600 nm.

[0037] In Step 3, the spin coating speed in the first step is 1000 rpm, the acceleration is 500 rpm / s, and the spin coating time is 10 s. The spin coating speed in the second step is 5000 rpm, the acceleration is 1000 rpm / s, and the spin coating time is 35 s.

[0038] Step 4: Prepare a layer of PC 61 BM as the electron transport layer. Add 20 mg of PC 61 BM powder into 1 ml of CB, and stir overnight at room temperature on a magnetic stirrer to obtain the PC 61 BM electron transport layer solution. Place the perovskite film prepared above on a spin coater, set the rotation speed program to 3000 rpm, the acceleration to 3000 rpm / s, for 30 s, and use a pipette to take 80 μl of PC 61 BM solution, and spin coat the solution on the perovskite film to prepare the electron transport layer with a thickness of about 25 nm.

[0039] Step 5: Prepare a layer of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as the buffer layer using the spin coating technique. Add 2 mg of BCP powder into 4 ml of IPA, and stir overnight at room temperature on a magnetic stirrer to obtain the BCP electron transport layer solution. Place the PC 61 BM film on a spin coater, set the rotation speed program to 6000 rpm, the acceleration to 3000 rpm / s, for 30 s, and use a pipette to take 120 μl of BCP solution, and spin coat the solution on the PC 61 BM film to prepare the buffer layer with a thickness of about 20 nm.

[0040] Step 6: Finally, use an evaporation coater to evaporate a metal electrode with a thickness of 100 nm as the back electrode at a speed of 0.5 Å / s.

[0041] In Step 6, the metal electrode includes gold, silver, copper, etc.

[0042] The perovskite solar cell based on the sericin-modified self-assembled monolayer is prepared by the preparation method described in Steps 1-6.

[0043] The beneficial effects of the present invention are as follows:

[0044] In the present invention, sericin is introduced into the perovskite precursor solution to adjust the size of perovskite grains during the film formation process and ensure the uniformity of grain size. The elasticity of sericin can guide the directional growth of grains and reduce grain boundary defects. On the other hand, the reducibility of sericin can inhibit the oxidation of iodide and ensure the stability of the perovskite film. At the same time, the water absorption of sericin can prevent water vapor from entering the perovskite film and prevent the perovskite film from being damaged. Brief Description of the Drawings

[0045] The relevant drawings of the technical solution are described as follows: To clearly illustrate the technical features of the embodiments of the present invention and the prior art solutions, the following will list the drawing files involved in the specific implementation manners. It should be noted that the drawings contained in this document are only representative implementation cases of the present invention. Those skilled in the relevant art can derive other implementation drawings based on the illustrated examples without creative work on the premise of fully understanding the technical key points of the present invention.

[0046] Figure 1 It is a schematic structural diagram of the perovskite solar cell of the present invention.

[0047] Figure 2 It is the surface SEM of the perovskite thin films obtained in Comparative Example 1 (a) and Example 2 (b) of the present invention.

[0048] Figure 3 It is the cross-sectional SEM of the perovskite thin film of Example 2 of the present invention.

[0049] Figure 4 It is the XRD curves of the perovskite thin films obtained in Comparative Example 1 and Example 2 of the present invention.

[0050] Figure 5 It is the J-V characteristic curve of the perovskite solar cell of the present invention tested under AM 1.5G sunlight, where Figure (a) is the comparison between Comparative Example 1 and Example 2, and Figure (b) is the comparison between Comparative Example 2 and Example 6.

[0051] Figure 6 It is the EQE curves of the perovskite solar cells obtained in Example 2 (a) and Example 6 (b) of the present invention. Detailed Description of the Invention

[0052] The present invention discloses a preparation method of a perovskite solar cell based on a sericin-modified perovskite layer. By introducing sericin into the perovskite precursor solution, the present invention solves the problems of poor crystallinity, rough surface and many defects of the perovskite thin film during the annealing process. The principle is to utilize the elasticity of sericin to guide the directional growth of grains, promote uniform nucleation and reduce grain boundary defects. On the other hand, by using the reducing property and water absorption of sericin, the oxidation of iodide is inhibited, water vapor intrusion into the perovskite thin film is avoided, and the photoelectric conversion efficiency and stability of the perovskite battery are improved. The present invention can promote the commercial application of perovskite solar cells and continuously break through the battery efficiency.

[0053] The following will describe the embodiments of the present invention in detail. These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0054] Comparative Example 1:

[0055] This comparative example uses a structure of a perovskite solar cell, and the preparation process includes the following steps:

[0056] 1. Select an FTO substrate with a size of 1.5 cm × 1.5 cm and sequentially place it in a detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min. Then place it in an oven at 80 °C for drying. After that, place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0057] 2. Preparation of the hole transport layer: Dissolve 20 mg of NiO x powder in 2 mL of ultrapure water and perform ultrasonic treatment for 30 min. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 100 μl of NiO x solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense NiO x layer with an appropriate thickness. After spin coating, anneal it on a hot plate at 110 °C for 20 min to finally obtain the NiO x layer with a thickness of about 20 nm. Deposit the SAM layer on the basis of the NiO x layer. Dissolve 2 mg of Me-4PACz powder in 4 mL of absolute ethanol to prepare the SAM layer solution. Take 100 µL of this solution and spin it at a rotation speed of 3000 rpm and an acceleration of 3000 rpm / s for 30 s. After spin coating, anneal it on a hot plate at 100 °C for 10 min to obtain the SAM layer.

[0058] 3. Deposit a perovskite thin film on the basis of the previous step. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, and 19.5 mg of CsI in 1 mL of a mixed solvent (DMF:DMSO = 4:1) respectively to obtain the FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then take 120 µL of the precursor solution and perform spin coating by the two-step method. Among them, the rotation speed of the first step of spin coating is 1000 rpm, the acceleration is 500 rpm / s, and the spin coating time is 10 s. The rotation speed of the second step of spin coating is 5000 rpm, the acceleration is 1000 rpm / s, and the spin coating time is 35 s. Add 200 µL of chlorobenzene (CB) as an antisolvent 15 s before the end of the second step of spin coating. After spin coating, anneal it on a hot plate at 120 °C for 10 min, and the film thickness is about 600 nm.

[0059] 4. Prepare a layer of PC 61BM as the electron transport layer. Add 20 mg of PC into 1 ml of CB 61 BM powder, and stir overnight at room temperature on a magnetic stirrer to obtain the PC 61 BM electron transport layer solution. Place the perovskite film prepared above on a spin coater, set the rotation speed program to 3000 rpm, the acceleration to 3000 rpm / s, for 30 s. Use a pipette to take 80 μl of the PC 61 BM solution, and spin-coat the solution on the perovskite film to prepare the electron transport layer with a thickness of about 25 nm.

[0060] 5. Use the spin-coating technique to prepare a layer of BCP as the buffer layer. Add 2 mg of BCP powder into 4 ml of IPA, and stir overnight at room temperature on a magnetic stirrer to obtain the BCP electron transport layer solution. Place the PC 61 BM film prepared above on a spin coater, set the rotation speed program to 6000 rpm, the acceleration to 3000 rpm / s, for 30 s. Use a pipette to take 120 μl of the BCP solution, and spin-coat the solution on the PC 61 BM film to prepare the buffer layer with a thickness of about 20 nm.

[0061] 6. Finally, use an evaporation coater with silver as the thermal evaporation source to evaporate a 100-nm-thick Ag layer as the back electrode at a speed of 0.5 Å / s.

[0062] Steps 1-6 are the methods for preparing a conventional inverted perovskite solar cell.

[0063] Example 1:

[0064] This example uses an inverted perovskite solar cell structure, and its preparation process and steps are as follows:

[0065] 1. Select a 1.5 cm × 1.5 cm FTO substrate, and sequentially place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min. Then place it in an 80°C oven to dry, and then place the cleaned conductive glass substrate in a UV-ozone generator for treatment for 30 min.

[0066] 2. Preparation of the hole transport layer: Dissolve 20 mg of NiO x powder in 2 mL of ultrapure water, and perform ultrasonic treatment for 30 min. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 100 μl of NiO x solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense NiO layer with a suitable thickness. x After spin-coating, anneal on a hot plate at 110°C for 20 min, and finally obtain NiO xlayer with a thickness of about 20 nm. On the NiO x layer, a SAM layer was deposited. 2 mg of Me-4PACz powder was dissolved in 4 mL of absolute ethanol to prepare a SAM layer solution. 100 µL of this solution was taken and spun at 3000 rpm with an acceleration of 3000 rpm / s for 30 s. After spin-coating, it was annealed on a hot plate at 100 °C for 10 min to obtain the SAM layer.

[0067] 3. On the basis of the previous step, a perovskite thin film was deposited. 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI and 0.5 mg of sericin were dissolved in 1 mL of a mixed solvent (DMF:DMSO = 4:1) respectively, so as to obtain the FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then 120 µL of the solution was spin-coated by a two-step method. Among them, the first step of spin-coating had a rotation speed of 1000 rpm, an acceleration of 500 rpm / s, and a spin-coating time of 10 s. The second step of spin-coating had a rotation speed of 5000 rpm, an acceleration of 1000 rpm / s, and a spin-coating time of 35 s. 200 µL of CB was added as an anti-solvent 15 s before the end of the second spin-coating. After spin-coating, it was annealed on a hot plate at 120 °C for 10 min, and the film thickness was about 600 nm.

[0068] 4. A layer of PC 61 BM was prepared as an electron transport layer by spin-coating technology. 20 mg of PC 61 BM powder was added to 1 ml of CB and stirred overnight at room temperature on a magnetic stirrer to obtain a PC 61 BM electron transport layer solution. The perovskite thin film prepared above was placed on a spin coater, and the rotation speed program was set to 3000 rpm, the acceleration was 3000 rpm / s, for 30 s. 80 μl of PC 61 BM solution was taken with a pipette and spin-coated on the perovskite thin film to prepare an electron transport layer with a thickness of about 25 nm.

[0069] 5. A layer of BCP was prepared as a buffer layer by spin-coating technology. 2 mg of BCP powder was added to 4 ml of IPA and stirred overnight at room temperature on a magnetic stirrer to obtain a BCP electron transport layer solution. The PC 61 BM thin film prepared above was placed on a spin coater, and the rotation speed program was set to 6000 rpm, the acceleration was 3000 rpm / s, for 30 s. 120 μl of BCP solution was taken with a pipette and spin-coated on the PC 61A buffer layer was prepared by spin-coating a solution on the BM film, with a thickness of approximately 20 nm.

[0070] 6. Finally, using an evaporation coater, with silver as the thermal evaporation source, a 100-nm-thick Ag layer was evaporated at a rate of 0.5 Å / s as the back electrode.

[0071] Example 2:

[0072] This example uses a structure of a p-i-n perovskite solar cell, and its preparation process and steps are as follows:

[0073] 1. A 1.5 cm × 1.5 cm FTO substrate was sequentially placed in detergent, deionized water, acetone, and absolute ethanol and sonicated for 30 min, then dried in an 80°C oven, and then the cleaned conductive glass substrate was placed in an ultraviolet-ozone apparatus for 30 min.

[0074] 2. Preparation of the hole transport layer: 20 mg of NiO x powder was dissolved in 2 mL of ultrapure water and sonicated for 30 min. After the ozone treatment, the transparent conductive substrate was placed on a spin coater, and 100 μl of NiO x solution was dropped each time. The rotation speed of the spin coater was adjusted to 3000 rpm to ensure the formation of a dense NiO x layer with a suitable thickness. After spin coating, it was annealed on a hot plate at 110°C for 20 min, and finally the NiO x layer was obtained, with a thickness of about 20 nm. On the basis of the NiO x layer, the SAM layer was deposited. 2 mg of Me-4PACz powder was dissolved in 4 mL of absolute ethanol to prepare the SAM layer solution. 100 µL of this solution was taken and rotated at 3000 rpm with an acceleration of 3000 rpm / s for 30 s. After spin coating, it was annealed on a hot plate at 100°C for 10 min to obtain the SAM layer.

[0075] 3. On the basis of the previous step, a perovskite thin film was deposited. 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 1.0 mg of sericin were respectively dissolved in 1 mL of a mixed solvent (DMF:DMSO = 4:1), so as to obtain FA 0.85 MA 0.1 Cs 0.05PbI3 precursor solution, and then take 120 µL of the solution and spin-coat it in a two-step method. Among them, the spinning speed in the first step of the two-step spin-coating is 1000 rpm, the acceleration is 500 rpm / s, and the spin-coating time is 10 s. The spinning speed in the second step is 5000 rpm, the acceleration is 1000 rpm / s, and the spin-coating time is 35 s. 200 µL of CB is added as an anti-solvent 15 s before the end of the second spin-coating. After the spin-coating is completed, it is annealed on a hot plate at 120 °C for 10 min, and the film thickness is approximately 600 nm.

[0076] 4. Prepare a layer of PC 61 BM as the electron transport layer. Add 20 mg of PC 61 BM powder to 1 ml of CB, and stir at room temperature overnight on a magnetic stirrer to obtain PC 61 BM electron transport layer solution. Place the perovskite film prepared above on a spin coater, set the rotation speed program to 3000 rpm, the acceleration to 3000 rpm / s, for 30 s, and use a pipette to take 80 μl of PC 61 BM solution, and spin-coat the solution on the perovskite film to prepare the electron transport layer with a thickness of approximately 25 nm.

[0077] 5. Prepare a layer of BCP as a buffer layer using the spin-coating technique. Add 2 mg of BCP powder to 4 ml of IPA, and stir at room temperature overnight on a magnetic stirrer to obtain the BCP electron transport layer solution. Place the PC 61 BM film prepared above on a spin coater, set the rotation speed program to 6000 rpm, the acceleration to 3000 rpm / s, for 30 s, and use a pipette to take 120 μl of BCP solution, and spin-coat the solution on the PC 61 BM film to prepare the buffer layer with a thickness of approximately 20 nm.

[0078] 6. Finally, use an evaporation coater with silver as the thermal evaporation source to evaporate a layer of Ag with a thickness of 100 nm as the back electrode at a speed of 0.5 Å / s.

[0079] Example 3:

[0080] This example uses a reverse perovskite solar cell structure, and its preparation process and steps are as follows:

[0081] 1. Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min, then place it in an 80 °C oven to dry, and then place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0082] 2. Hole transport layer preparation: Dissolve 20 mg of NiOx The powder was dissolved in 2 mL of ultrapure water and treated by ultrasonic for 30 min. The transparent conductive substrate after ozone treatment was placed on a spin coater, and 100 μl of NiO solution was dropped each time. x The rotation speed of the spin coater was adjusted to 3000 rpm to ensure the formation of a dense NiO layer with a suitable thickness. x After spin coating, it was annealed on a hot plate at 110 °C for 20 min, and finally the NiO layer was obtained, with a thickness of about 20 nm. x On the basis of the NiO layer, the SAM layer was deposited. 2 mg of Me-4PACz powder was dissolved in 4 mL of absolute ethanol to prepare the SAM layer solution. 100 µL of this solution was taken and spun at a rotation speed of 3000 rpm and an acceleration of 3000 rpm / s for 30 s. After spin coating, it was annealed on a hot plate at 100 °C for 10 min to obtain the SAM layer. x

[0083] 3. On the basis of the previous step, a perovskite thin film was deposited. 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI and 1.5 mg of sericin were dissolved in 1 mL of mixed solvent (DMF:DMSO = 4:1) respectively, so as to obtain the FAMA CsPbI3 precursor solution. Then, 120 µL of the solution was spin-coated by a two-step method. Among them, the rotation speed of the first step of spin coating was 1000 rpm, the acceleration was 500 rpm / s, and the spin coating time was 10 s. The rotation speed of the second step of spin coating was 5000 rpm, the acceleration was 1000 rpm / s, and the spin coating time was 35 s. 200 µL of CB was added as an antisolvent 15 s before the end of the second spin coating. After spin coating, it was annealed on a hot plate at 120 °C for 10 min, and the film thickness was about 600 nm. 0.85 MA 0.1 Cs 0.05

[0084] 4. A layer of PCBM was prepared as the electron transport layer by spin coating technology. 20 mg of PCBM powder was added to 1 ml of CB, and stirred overnight at room temperature on a magnetic stirrer to obtain the PCBM electron transport layer solution. The perovskite thin film prepared above was placed on a spin coater, and the rotation speed program was set to 3000 rpm, the acceleration was 3000 rpm / s, and for 30 s. 80 μl of PCBM solution was taken with a pipette and spin-coated on the perovskite thin film to prepare the electron transport layer, with a thickness of about 25 nm. 61 61 61 61

[0085] 5. Prepare a layer of BCP as a buffer layer using the spin-coating technique. Add 2 mg of BCP powder to 4 ml of IPA and stir overnight at room temperature on a magnetic stirrer to obtain the BCP electron transport layer solution. Place the PC 61 BM film prepared above on a spin coater, set the rotation speed program to 6000 rpm, the acceleration to 3000 rpm / s, for 30 s. Use a pipette to take 120 μl of the BCP solution and spin-coat the solution on the PC 61 BM film to prepare the buffer layer, with a thickness of approximately 20 nm.

[0086] 6. Finally, use an evaporation coater with silver as the thermal evaporation source to evaporate a 100-nm-thick Ag layer as the back electrode at a rate of 0.5 Å / s.

[0087] Example 4:

[0088] This example uses a reverse perovskite solar cell structure, and its preparation process and steps are as follows:

[0089] 1. Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min, then dry it in an 80°C oven. Then place the cleaned conductive glass substrate in an ultraviolet-ozone apparatus for treatment for 30 min.

[0090] 2. Preparation of the hole transport layer: Dissolve 20 mg of NiO x powder in 2 mL of ultrapure water and perform ultrasonic treatment for 30 min. Place the transparent conductive substrate after ozone treatment on a spin coater and drop 100 μl of NiO x solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense and appropriate-thickness NiO x layer. After spin coating, anneal it on a hot plate at 110°C for 20 min to finally obtain the NiO x layer, with a thickness of about 20 nm. Deposit the SAM layer on the basis of the NiO x layer. Dissolve 2 mg of Me-4PACz powder in 4 mL of absolute ethanol to prepare the SAM layer solution. Take 100 µL of this solution and spin it at a rotation speed of 3000 rpm and an acceleration of 3000 rpm / s for 30 s. After spin coating, anneal it on a hot plate at 100°C for 10 min to obtain the SAM layer.

[0091] 3. On the basis of the previous step, deposit a perovskite thin film. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 2.0 mg of sericin in 1 mL of a mixed solvent (DMF:DMSO = 4:1) to obtain a FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then take 120 µL of the solution and spin-coat it in two steps. Among them, the first step of spin-coating has a rotation speed of 1000 rpm, an acceleration of 500 rpm / s, and a spin-coating time of 10 s. The second step of spin-coating has a rotation speed of 5000 rpm, an acceleration of 1000 rpm / s, and a spin-coating time of 35 s. Add 200 µL of CB as an anti-solvent 15 s before the end of the second spin-coating. After spin-coating, anneal on a hot plate at 120 °C for 10 min, and the film thickness is approximately 600 nm.

[0092] 4. Use the spin-coating technique to prepare a layer of PC 61 BM as the electron transport layer. Add 20 mg of PC 61 BM powder to 1 ml of CB, and stir at room temperature overnight on a magnetic stirrer to obtain a PC 61 BM electron transport layer solution. Place the perovskite thin film prepared above on a spin coater, set the rotation speed program to 3000 rpm, the acceleration to 3000 rpm / s, for 30 s. Use a pipette to take 80 μl of PC 61 BM solution, and spin-coat the solution on the perovskite thin film to prepare the electron transport layer, with a thickness of approximately 25 nm.

[0093] 5. Use the spin-coating technique to prepare a layer of BCP as the buffer layer. Add 2 mg of BCP powder to 4 ml of IPA, and stir at room temperature overnight on a magnetic stirrer to obtain a BCP electron transport layer solution. Place the PC 61 BM thin film prepared above on a spin coater, set the rotation speed program to 6000 rpm, the acceleration to 3000 rpm / s, for 30 s. Use a pipette to take 120 μl of BCP solution, and spin-coat the solution on the PC 61 BM thin film to prepare the buffer layer, with a thickness of approximately 20 nm.

[0094] 6. Finally, use an evaporation coater, with silver as the thermal evaporation source, and evaporate a 100-nm-thick Ag as the back electrode at a speed of 0.5 Å / s.

[0095] Comparative Example 2:

[0096] This comparative example uses the formal perovskite solar cell structure, and its preparation process and steps are as follows:

[0097] 1. Select an FTO substrate with a size of 1.5 cm × 1.5 cm and sequentially place it into a detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min. Then place it in an 80°C oven to dry. After that, place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0098] 2. Preparation of the electron transport layer: Mix the SnO2 stock solution and ultrapure water in a volume ratio of 1:5 and prepare it by ultrasonic treatment for 30 minutes. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 110 μl of the SnO2 dilution solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense SnO2 layer with an appropriate thickness. After spin coating, anneal it on a heating stage at 150°C for 40 min to finally obtain the electron transport layer with a thickness of about 25 nm.

[0099] 3. Deposit a perovskite thin film on the basis of the electron transport layer. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, and 19.5 mg of CsI in 1 mL of a mixed solvent (DMF:DMSO = 4:1) respectively, so as to obtain the FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then take 120 µL of the solution and perform spin coating by the two-step method. Among them, the rotation speed of the first step of the two-step spin coating is 1000 rpm, the acceleration is 500 rpm / s, and the spin coating time is 10 s. The rotation speed of the second step of spin coating is 5000 rpm, the acceleration is 1000 rpm / s, and the spin coating time is 35 s. Add 200 µL of CB as an anti-solvent 15 s before the end of the second step of spin coating. After spin coating, anneal it on a hot plate at 120°C for 10 min, and the film thickness is about 600 nm.

[0100] 4. A layer of Spiro-OMeTAD is prepared as the hole transport layer using the spin-coating technique. 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder is added to 1 ml of acetonitrile (ACN) and stirred at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain a lithium salt solution; 450 mg of FK209 powder is added to 1 ml of ACN and stirred at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain an FK209 solution. 71 mg of Spiro-OMeTAD, 27 μl of the lithium salt, 35.6 μl of the TBP solution, 28.5 μl of the FK209 solution, and 1 ml of chlorobenzene are weighed and added to a 3-ml glass bottle to prepare a Spiro-OMeTAD hole transport layer solution. The perovskite thin film prepared above is placed on a homogenizer, the rotation speed program is set to 5000 rpm, the acceleration is 2500 rpm / s, for 30 s, and 70 μl of the Spiro-OMeTAD solution is weighed using a pipette and spin-coated dynamically on the perovskite thin film to prepare the hole transport layer with a thickness of approximately 100 nm.

[0101] 5. Finally, using an evaporation coater, with silver as the thermal evaporation source, a 100-nm-thick Ag layer is evaporated at a speed of 0.5 Å / s as the back electrode.

[0102] Steps 1-5 are the methods for preparing a conventional formal perovskite solar cell.

[0103] Example 5:

[0104] This example adopts a formal perovskite solar cell structure, and its preparation process and steps are as follows:

[0105] 1. A 1.5 cm × 1.5 cm FTO substrate is selected and successively placed in a detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min, then dried in an 80°C oven, and then the cleaned conductive glass substrate is placed in an ultraviolet-ozone device for treatment for 30 min.

[0106] 2. Preparation of the electron transport layer: The SnO2 stock solution is mixed with ultrapure water in a volume ratio of 1:5 and prepared by ultrasonic treatment for 30 minutes. The transparent conductive substrate after ozone treatment is placed on a spin coater, and 110 μl of the SnO2 dilution is dropped each time. The rotation speed of the spin coater is adjusted to 3000 rpm to ensure the formation of a dense and appropriate-thickness SnO2 layer. After spin coating, it is annealed on a 150°C heating table for 40 min, and finally the electron transport layer is prepared with a thickness of about 25 nm.

[0107] 3. On the basis of the previous step, deposit a perovskite thin film. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 0.5 mg of sericin in 1 mL of a mixed solvent (DMF:DMSO = 4:1) to obtain a FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution. Then, take 120 µL of the solution and spin-coat it using a two-step method. For the two-step spin-coating, the rotation speed in the first step is 1000 rpm, the acceleration is 500 rpm / s, and the spin-coating time is 10 s. The rotation speed in the second step is 5000 rpm, the acceleration is 1000 rpm / s, and the spin-coating time is 35 s. Add 200 µL of CB as an anti-solvent 15 s before the end of the second spin-coating. After spin-coating, anneal on a hot plate at 120 °C for 10 min. The thickness of the thin film is approximately 600 nm.

[0108] 4. Use the spin-coating technique to prepare a layer of Spiro-OMeTAD as the hole transport layer. Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 ml of acetonitrile (ACN) and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain a lithium salt solution; add 450 mg of FK209 powder to 1 ml of ACN and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain an FK209 solution. Weigh 71 mg of Spiro-OMeTAD, 27 μl of the lithium salt solution, 35.6 μl of the TBP solution, 28.5 μl of the FK209 solution, and 1 ml of chlorobenzene and add them to a 3-ml glass bottle to prepare a Spiro-OMeTAD hole transport layer solution. Place the perovskite thin film prepared above on a homogenizer, set the rotation speed program to 5000 rpm, the acceleration to 2500 rpm / s, and the time to 30 s. Use a pipette to weigh 70 μl of the Spiro-OMeTAD solution and dynamically spin-coat the solution on the perovskite thin film to prepare the hole transport layer with a thickness of approximately 100 nm.

[0109] 5. Finally, use an evaporation coater with silver as the thermal evaporation source to evaporate a 100-nm-thick Ag layer as the back electrode at a speed of 0.5 Å / s.

[0110] Example 6:

[0111] This example adopts a formal perovskite solar cell structure, and its preparation process and steps are as follows:

[0112] 1. Select an FTO substrate with a size of 1.5 cm × 1.5 cm and sequentially place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min. Then place it in an 80 °C oven to dry. After that, place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0113] 2. Preparation of the electron transport layer: Mix the SnO2 stock solution and ultrapure water in a volume ratio of 1:5 and prepare it by ultrasonic treatment for 30 minutes. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 110 μl of the SnO2 dilution solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense SnO2 layer with a suitable thickness. After spin coating, anneal it on a heating table at 150 °C for 40 min to finally obtain the electron transport layer with a thickness of about 25 nm.

[0114] 3. Deposit a perovskite thin film on the basis of the previous step. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 1.0 mg of sericin in 1 mL of a mixed solvent (DMF:DMSO = 4:1) to obtain a FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then take 120 µL of the solution and perform spin coating by the two-step method. Among them, the rotation speed of the first step of the two-step spin coating is 1000 rpm, the acceleration is 500 rpm / s, and the spin coating time is 10 s. The rotation speed of the second step of spin coating is 5000 rpm, the acceleration is 1000 rpm / s, and the spin coating time is 35 s. Add 200 µL of CB as an anti-solvent 15 s before the end of the second step of spin coating. After spin coating, anneal it on a hot plate at 120 °C for 10 min, and the film thickness is approximately 600 nm.

[0115] 4. Prepare a layer of Spiro-OMeTAD as the hole transport layer using the spin-coating technique. Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 ml of acetonitrile (ACN), and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain a lithium salt solution; add 450 mg of FK209 powder to 1 ml of ACN, and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain an FK209 solution. Weigh 71 mg of Spiro-OMeTAD, 27 μl of the lithium salt solution, 35.6 μl of TBP solution, 28.5 μl of FK209 solution, and 1 ml of chlorobenzene, and add them to a 3-ml glass bottle to prepare a Spiro-OMeTAD hole transport layer solution. Place the perovskite film prepared above on a homogenizer, set the rotation speed program to 5000 rpm, the acceleration to 2500 rpm / s, for 30 s. Use a pipette to weigh 70 μl of the Spiro-OMeTAD solution, and dynamically spin-coat the solution on the perovskite film to prepare a hole transport layer with a thickness of approximately 100 nm.

[0116] 5. Finally, use an evaporation coater with silver as the thermal evaporation source to evaporate a 100-nm-thick Ag layer as the back electrode at a speed of 0.5 Å / s.

[0117] Example 7:

[0118] This example uses a formal perovskite solar cell, and its preparation process and steps are as follows:

[0119] 1. Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min in sequence. Then place it in an 80°C oven to dry, and then place the cleaned conductive glass substrate in an ultraviolet-ozone generator for treatment for 30 min.

[0120] 2. Preparation of the electron transport layer: Mix the SnO2 stock solution and ultrapure water in a volume ratio of 1:5 and ultrasonically treat for 30 minutes. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 110 μl of the SnO2 dilution solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense and appropriate-thickness SnO2 layer. After spin coating, anneal on a 150°C heating platform for 40 min to finally obtain an electron transport layer with a thickness of about 25 nm.

[0121] 3. Deposit a perovskite film on the basis of the previous step. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 1.5 mg of sericin in 1 mL of a mixed solvent (DMF:DMSO = 4:1) to obtain FA 0.85 MA0.1 Cs 0.05 For the PbI3 precursor solution, 120 μL of the solution was spin-coated in a two-step method. Among them, the spin-coating speed in the first step of the two-step spin-coating was 1000 rpm, the acceleration was 500 rpm / s, the spin-coating time was 10 s, the spin-coating speed in the second step was 5000 rpm, the acceleration was 1000 rpm / s, and the spin-coating time was 35 s. 200 μL of CB was dropped as an anti-solvent 15 s before the end of the second-step spin-coating. After the spin-coating was completed, it was annealed on a hot plate at 120 °C for 10 min, and the film thickness was approximately 600 nm.

[0122] 4. Use the spin-coating technique to prepare a layer of Spiro-OMeTAD as the hole transport layer. Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 ml of acetonitrile (ACN), and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain the lithium salt solution; add 450 mg of FK209 powder to 1 ml of ACN, and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain the FK209 solution. Weigh 71 mg of Spiro-OMeTAD, 27 μl of the lithium salt, 35.6 μl of the TBP solution, 28.5 μl of the FK209 solution, and 1 ml of chlorobenzene and add them to a 3-ml glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Place the perovskite film prepared above on a homogenizer, set the rotation speed program to 5000 rpm, the acceleration to 2500 rpm / s, and 30 s. Use a pipette to weigh 70 μl of the Spiro-OMeTAD solution, and dynamically spin-coat the solution on the perovskite film to prepare the hole transport layer with a thickness of approximately 100 nm.

[0123] 5. Finally, use an evaporation instrument, with silver as the thermal evaporation source, and evaporate a 100-nm-thick Ag layer as the back electrode at a speed of 0.5 Å / s.

[0124] Example 8:

[0125] This example adopts the formal perovskite solar cell structure, and its preparation process and steps are as follows:

[0126] 1. Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, acetone, and absolute ethanol for ultrasonic treatment for 30 min, then place it in an 80 °C oven to dry, and then place the cleaned conductive glass substrate in a UV-ozone generator for treatment for 30 min.

[0127] 2. Preparation of the electron transport layer: Prepared by mixing the SnO2 stock solution and ultrapure water in a volume ratio of 1:5 and sonicating for 30 minutes. Place the transparent conductive substrate after ozone treatment on a spin coater, and drop 110 μl of the SnO2 dilution solution each time. Adjust the rotation speed of the spin coater to 3000 rpm to ensure the formation of a dense SnO2 layer with an appropriate thickness. After spin coating, anneal on a heating table at 150 °C for 40 min to finally obtain the electron transport layer with a thickness of about 25 nm.

[0128] 3. Deposit a perovskite thin film on the basis of the previous step. Dissolve 726.5 mg of PbI2, 219.2 mg of FAI, 23.8 mg of MAI, 19.5 mg of CsI, and 2.0 mg of sericin in 1 mL of a mixed solvent (DMF:DMSO = 4:1) respectively, so as to obtain the FA 0.85 MA 0.1 Cs 0.05 PbI3 precursor solution, and then take 120 µL of the solution and spin coat it by the two-step method. Among them, the rotation speed of the first step of the two-step spin coating is 1000 rpm, the acceleration is 500 rpm / s, the spin coating time is 10 s, the rotation speed of the second step of the spin coating is 5000 rpm, the acceleration is 1000 rpm / s, and the spin coating time is 35 s. Add 200 µL of CB as an anti-solvent 15 s before the end of the second step of spin coating. After spin coating, anneal on a hot plate at 120 °C for 10 min, and the film thickness is about 600 nm.

[0129] 4. Use the spin coating technique to prepare a layer of Spiro-OMeTAD as the hole transport layer. Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 ml of acetonitrile (ACN), and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain the lithium salt solution; add 450 mg of FK209 powder to 1 ml of ACN, and stir at room temperature on a magnetic stirrer for 3 hours until dissolved to obtain the FK209 solution. Weigh 71 mg of Spiro-OMeTAD, 27 μl of the lithium salt, 35.6 μl of the TBP solution, 28.5 μl of the FK209 solution, and 1 ml of chlorobenzene and add them to a 3 ml glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Place the perovskite thin film prepared above on a homogenizer, set the rotation speed program to 5000 rpm, the acceleration to 2500 rpm / s, and 30 s. Use a pipette gun to weigh 70 μl of the Spiro-OMeTAD solution and dynamically spin coat the solution on the perovskite thin film to prepare the hole transport layer with a thickness of about 100 nm.

[0130] 5. Finally, use an evaporation coater, with silver as the thermal evaporation source, and evaporate a 100 nm thick Ag layer as the back electrode at a speed of 0.5 Å / s.

[0131] Test results:

[0132] The performance of the above-mentioned perovskite solar cells prepared in Comparative Example 1 and Examples 1-4 was tested. Under standard test conditions (AM 1.5G, 25 °C, 100 mW / cm 2 ), the photovoltaic performance parameters such as open-circuit voltage, short-circuit current, fill factor, and cell conversion efficiency were tested respectively. The test results are shown in Table 1.

[0133]

[0134] The performance of the above-mentioned perovskite solar cells prepared in Comparative Example 2 and Examples 5-8 was tested. Under standard test conditions (AM 1.5G, 25 °C, 100 mW / cm 2 ), the photovoltaic performance parameters such as open-circuit voltage, short-circuit current, fill factor, and cell conversion efficiency were tested respectively. The test results are shown in Table 2.

[0135]

[0136] As can be seen from Table 1, the performance of the perovskite solar cells prepared by adding sericin has been significantly improved, especially the improvement of the current density and fill factor of the cells is more obvious. Among them, in Example 2, the photoelectric conversion efficiency prepared by adding 1.0 mg of sericin reached 24.17%. As can be seen from Table 2, the performance of the perovskite solar cells prepared by adding sericin has also been significantly improved, and the improvement of the current density and fill factor of the cells is more obvious. Among them, in Example 6, the photoelectric conversion efficiency prepared by adding 1.0 mg of sericin reached 24.11%.

[0137] As Figure 1 is a schematic structural diagram of the perovskite solar cell of the present invention. The SEM images of the perovskite thin films in the perovskite solar cells of Example 2 and Comparative Example 1 are as Figure 2 shown. As Figure 2 shown, the perovskite thin film of Example 2 (right figure) presents a smooth and dense structure, with blurred grain boundaries and relatively uniform grain sizes; while the thin film of Comparative Example 1 (left figure) has clear grain boundaries, uneven grain sizes, and there is some unreacted lead iodide. The presence of lead iodide will affect the performance of the cell, and grain boundary defects will hinder the carrier transport, resulting in a significant decrease in the device performance. Figure 3 is the interfacial SEM image of the perovskite layer of Example 2 of the present invention. It can be seen that the thickness of the perovskite layer is relatively uniform and the film-forming quality is good. Figure 4XRD comparison diagram of the perovskite layers in Example 2 and Comparative Example 1 of the present invention. The higher intensity of the main XRD peak in Example 2 than that in Comparative Example indicates better crystallization effect. It can be seen from the SEM diagram and XRD diagram that the film quality is improved, the crystallization effect is improved, and the defects are reduced by adding 1.0 mg of sericin in Example 2. The J-V curves of the perovskite solar cells obtained in Example 2 and Comparative Example 1 are as Figure 5 shown in (a). It can be seen that the current density of Example 2 has a significant increase. The J-V curves of the perovskite solar cells obtained in Example 6 and Comparative Example 2 are as Figure 5 shown in (b). It can be seen that the current density of Example 6 also has a significant increase. According to Figure 5 it can be illustrated that adding sericin can increase the current density to a certain extent, thereby improving the photoelectric conversion efficiency of the battery. Figure 6 (a) is the EQE diagram of the perovskite solar cell obtained in Example 2 of the present invention. The current density measured by EQE is 24.55 mA / cm 2 , and the error from the current density of 25.67 mA / cm 2 measured under AM 1.5G sunlight is about 4.36%. Figure 6 (b) is the EQE diagram of the perovskite solar cell obtained in Example 6 of the present invention. The current density measured by EQE is 24.45 mA / cm 2 , and the error from the current density of 25.67 mA / cm 2 measured under AM 1.5G sunlight is about 4.75%.

Claims

1. A preparation method of a sericin protein-modified perovskite thin film, characterized in that: Sericin protein is added as an additive to the perovskite precursor solution, and the perovskite thin film material is prepared by an anti-solvent method.

2. The preparation method according to claim 1, characterized in that: A perovskite precursor solution is prepared according to the element composition of the perovskite thin film material, wherein the perovskite thin film material is ABX3, wherein A is FA + 、MA + , Cs + Any one or more of the following, B is Pb 2+ , X is I ﹣ , Cl ﹣ Br ﹣ Any one or more of the .

3. The preparation method according to claim 2, wherein It includes the following steps: Adding the perovskite precursor to a mixed solvent, adding sericin protein, and obtaining a mixed precursor solution after uniform dispersion; taking the mixed precursor solution and performing spin coating by the anti-solvent method, and dropping the anti-solvent 15 s before the end of spin coating, and annealing after the end of spin coating to obtain the perovskite thin film material.

4. The preparation method according to claim 3, characterized in that: The mixed solvent is composed of a DMF and DMSO compound, and the volume ratio of the two is 4:

1.

5. The preparation method according to claim 3, characterized in that: In the mixed precursor solution, the concentration of sericin protein is 0.5-2.0 mg / mL.

6. The preparation method according to claim 3, characterized in that: The spin coating parameters of the anti-solvent method are as follows: first, the rotation speed is increased to 1000 rpm at an acceleration of 500 rpm / s to assist the spreading of the precursor solution, and the spin coating time is 10 s; then immediately the rotation speed is increased to 5000 rpm at 1000 rpm / s, and the spin coating time is 35 s.

7. The preparation method according to claim 3, characterized in that: The anti-solvent is chlorobenzene, diethyl ether, ethyl acetate or anisole.

8. The preparation method according to claim 3, characterized in that: The annealing temperature is 120 °C and the time is 10 min.

9. Application of the sericin protein-modified perovskite thin film prepared by any one of the preparation methods of claims 1-8 in constructing a perovskite solar cell.

10. The application according to claim 9, characterized in that: Using the sericin protein-modified perovskite thin film as the perovskite light-absorbing layer, and the thickness range of the perovskite light-absorbing layer is 500-700 nm.

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