Method for modifying and optimizing performance of perovskite solar cell through hole transport layer

Abstract

The invention discloses a method for modifying and optimizing the performance of a perovskite solar cell through a hole transport layer, and belongs to the field of perovskite solar cells. According to the invention, the hole transport layer is modified at low cost, so that the problems that a perovskite solution is difficult to spread on the surface of the SAM layer and a uniform perovskite thin film cannot be formed due to irregular oriented growth of an SAM layer end chain on the substrate are solved. According to the method, the wettability of the perovskite solution on the surface of the hole transport layer can be effectively improved, uniform film forming of the perovskite precursor solution on the hole transport layer is assisted, the film forming quality of the perovskite light absorption layer is improved, and the photoelectric conversion efficiency and the light stability of the wide-band-gap perovskite solar cell are further improved.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and in particular relates to a method for optimizing the performance of perovskite solar cells by modifying a hole transport layer. Background Art

[0002] Current environmentally friendly new energy sources primarily include wind, tidal, biomass, and solar energy. Solar energy, as a new renewable energy source, holds enormous development potential. Solar cells have undergone three generations of development. Perovskite solar cells, a novel third-generation thin-film cell, offer advantages such as high conversion efficiency, adjustable bandgap, low production costs, and the ability to fabricate tandem cells. They have currently achieved a certified efficiency of 26.95%, comparable to commercial crystalline silicon cells. Limited by the Shockley-Queisser (SQ) theoretical efficiency limit, conventional single-junction cells can only achieve an efficiency of around 30%. Therefore, constructing tandem cells is an effective way to significantly improve cell efficiency. Tandem cells have achieved theoretical efficiencies as high as 45%, far exceeding the 33% SQ limit of a single-junction cell. While conventional III-V semiconductor tandem cells have achieved relatively high efficiencies, they are expensive and complex to manufacture. Tandem cells such as wide-bandgap perovskite / narrow-bandgap perovskite (all-perovskite stack), wide-bandgap perovskite / crystalline silicon (crystalline silicon perovskite stack), and wide-bandgap perovskite / organic thin film (organic perovskite stack) are important technical means to achieve high-efficiency and low-cost photovoltaic cells.

[0003] Wide-bandgap perovskite cells are widely used as top cells in tandem cells. However, the incorporation of large amounts of cesium and bromide ions into the wide-bandgap perovskite light-absorbing layer leads to problems such as poor crystallinity, surface roughness, and numerous defects. Furthermore, the perovskite solution struggles to spread evenly across the SAM layer, resulting in low photoelectric conversion efficiency and stability in the resulting devices. This severely hinders the further development of wide-bandgap perovskite solar cells and tandem cells. Summary of the Invention

[0004] The present invention addresses the problems of the above-mentioned prior art by providing a method for optimizing the performance of perovskite solar cells by modifying the hole transport layer. This method addresses the difficulty in uniformly coating the perovskite layer on the SAM layer in NiOx-free inverse wide-bandgap perovskite solar cells. By modifying the hole transport layer at low cost, the present invention effectively increases the wettability of the perovskite solution on the hole transport layer surface, assisting in the uniform film formation of the perovskite precursor solution on the hole transport layer, improving the film formation quality of the perovskite light-absorbing layer, and further enhancing the photoelectric conversion efficiency and light stability of the wide-bandgap perovskite solar cell.

[0005] The method of the present invention for optimizing the performance of perovskite solar cells by modifying the hole transport layer comprises adding an additive to a SAM solution to prepare a modified SAM layer, and then preparing a perovskite layer by two-step spin coating on the SAM layer.

[0006] The SAM molecules contained in the SAM solution are Me-4PACz or Me-2PACz, and the solution concentration is 0.5 mg / mL.

[0007] The additives are PbI2 and FAI.

[0008] Furthermore, the mass ratio of SAM molecules, PbI2 and FAI is 1:5-10:5-10.

[0009] The SAM molecules are arranged vertically on the ITO glass surface and horizontally on the glass surface. The horizontally arranged SAM molecules lack effective binding sites, resulting in the inability of the perovskite solution to effectively wet the surface of the SAM layer, and it is impossible to prepare a uniform perovskite layer film. The low-cost method of modifying the hole transport layer of the present invention is to introduce PbI2 and FAI into the SAM layer precursor solution so that the perovskite solution has a smaller wetting angle on the surface of the SAM layer, thereby solving the problem that the perovskite solution is difficult to coat on the SAM layer. The added PbI2 and FAI are evenly distributed in the SAM layer, providing effective binding sites for the perovskite layer. At the same time, the strong interaction between FAI and the PbI2 precursor solution effectively increases the wettability of the perovskite solution, assists the spreading of the perovskite solution, promotes the uniform film formation of the perovskite, and improves the film formation quality of the perovskite film and the photoelectric conversion efficiency of the device.

[0010] The perovskite solar cell is of PIN type, and its structure from bottom to top is sequentially arranged as a transparent conductive substrate, a p-type hole transport layer, a wide bandgap perovskite light absorption layer, an n-type electron transport layer and a metal electrode.

[0011] Specifically, in the pin structure:

[0012] The transparent conductive substrate is indium tin oxide (ITO) or fluorine-doped indium tin oxide (FTO), but is not limited to the transparent conductive substrates listed above.

[0013] The p-type hole transport layer can be made of one or more p-type semiconductor materials selected from polystyrene sulfonate (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), redox graphene, [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid (Me-2PACz), 4-butyl-N,N-diphenylaniline homopolymer (PloyTPD), etc., but is not limited to the materials listed above.

[0014] The wide bandgap perovskite light absorbing layer is ABX3, where 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 .

[0015] The n-type electron transport layer may be C 60 、PC 60 BM, PC 61 The BM is made of one or more n-type semiconductor materials, but is not limited to the above materials.

[0016] The metal electrodes are gold (Au), silver (Ag), copper (Cu), etc., but are not limited to the metal electrodes listed above.

[0017] The purpose of the present invention is to provide a method for preparing the above-mentioned wide bandgap perovskite solar cell. Here, the preparation process of a PIN-type titanite solar cell is taken as an example. The steps are as follows:

[0018] Step 1: Select ITO glass as the conductive glass substrate and clean it sequentially with detergent, deionized water, acetone, and ethanol, each cleaning step performed under ultrasound. After each cleaning step, dry the substrate in an 80°C air drying oven and then perform a UV-ozone treatment.

[0019] In step 1, the ultrasonic treatment time is 15-20 min.

[0020] In step 1, the drying time in the blast drying oven is 6-8 h.

[0021] In step 1, the UV-ozone treatment time is 5-20 min.

[0022] Step 2: Prepare the hole transport layer using spin coating. Prepare the modified hole transport layer masterbatch. Place the UV-ozone-treated ITO transparent conductive substrate on a spin coater and drip 80 μL of the masterbatch at a time. Adjust the spin coater speed to ensure a dense SAM layer of appropriate thickness. After spin coating, anneal the mixture on a heating plate at 100-120°C for 10 minutes to complete the hole transport layer.

[0023] In step 2, the spin coating speed is 3000-4000 rpm, and the working time is 25-35 s.

[0024] In step 2, the material used for the hole transport layer is Me-4PACz or Me-2PACz.

[0025] Step 3: Based on the previous step, a wide-bandgap perovskite film was prepared by two-step spin coating. Precursor solutions A and B were prepared separately. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO = 4:1) to prepare Precursor Solution A. 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare Precursor Solution B. 100 μL of Precursor Solution A was dropwise added to the ITO conductive substrate, followed by 100 μL of Precursor Solution B. After annealing, the wide-bandgap perovskite film was prepared.

[0026] In step 3, the spin coating speed of precursor solution A was 3000 rpm, the spin coating time was 30 s, and the spin coating acceleration was 2000 rpm / s. The spin coating speed of precursor solution B was 3500 rpm, the spin coating time was 30 s, and the spin coating acceleration was 2000 rpm / s.

[0027] Step 4: Spin-coat a passivation layer on the perovskite film prepared in step 3. PEAI was selected as the passivation agent, dissolved in isopropyl alcohol (IPA) at a concentration of 0.5 mg / mL. The spin coating speed was 5000 rpm for 30 s.

[0028] Step 5: Prepare PCBM as an electron transport layer using spin coating. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution onto the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0029] Step 6: Prepare the BCP layer using spin coating technology. Dissolve BCP in isopropyl alcohol (IPA) to make a solution with a concentration of 0.5 mg / mL. Stir overnight. Set the spin coater speed program to 6000 rpm, acceleration to 5000 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 110 μL of BCP solution and static spin coating to prepare the BCP layer.

[0030] Step 7: Use an evaporator to evaporate a 100 nm thick metal electrode as the back electrode on the ITO conductive substrate at a rate of 0.5 Å / s.

[0031] In step 7, the metal electrode includes gold, silver, copper, etc.

[0032] A wide-bandgap titanite solar cell with a modified hole transport layer is prepared by the preparation method described in steps 1-7.

[0033] The present invention has the following beneficial effects:

[0034] 1. The present invention introduces a portion of PbI2 and FAI into the hole transport layer to modify the hole transport layer. PbI2 and FAI are evenly dispersed in the SAM layer, adjusting the orientation of the SAM molecules to a certain extent.

[0035] 2. Modify the hole transport layer by introducing some PbI2 and FAI into the hole transport layer. This low-cost modification method provides binding sites for the perovskite solution on the surface of the SAM layer, assisting the spreading of the perovskite solution.

[0036] 3. When preparing perovskite films by a two-step method, the PbI2 precursor solution used in the first step has a strong interaction with FAI. This strong interaction is conducive to the combination of the perovskite solution and the SAM layer, and assists the uniform formation of the perovskite layer.

[0037] Through this method, the wettability of the perovskite solution can be effectively increased, the spreading of the perovskite solution can be assisted, and the quality and performance of the perovskite film can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings related to 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 diagrams and files related to the specific implementation methods are listed. It should be noted that the drawings contained in this document are only representative implementation examples of the present invention. Those skilled in the relevant art can deduce other implementation diagrams based on the illustrated examples without inventive work, provided that they fully understand the technical key points of the present invention.

[0039] Figure 1 Schematic diagram of the structure of the wide-bandgap perovskite solar cell prepared by the present invention.

[0040] Figure 2 Schematic diagram of the structure of the flexible wide-bandgap perovskite solar cell prepared by the present invention.

[0041] Figure 3 Band gap diagram of the wide band gap perovskite solar cell prepared in the present invention.

[0042] Figure 4 The coverage of the perovskite solution on the surface of the SAM layer after the unmodified (a) and modified (b) SAM of the present invention.

[0043] Figure 5 These are SEM images of perovskite films prepared on the surfaces of unmodified (a) and modified (b) SAMs of the present invention.

[0044] Figure 6 This is an SEM image of the interface thickness of the wide-bandgap perovskite film prepared in the present invention.

[0045] Figure 7 The JV characteristic curves of the wide-bandgap perovskite solar cells prepared with the unmodified SAM and the modified SAM of the present invention tested under AM1.5G.

[0046] Figure 8 This is a stability test chart of the wide-bandgap perovskite solar cell prepared with the unmodified SAM and the modified SAM of the present invention under continuous illumination at AM1.5G. DETAILED DESCRIPTION

[0047] The present invention discloses an application of a low-cost modified hole transport layer in the preparation of a wide-bandgap perovskite solar cell. The present invention solves the problem of the difficulty of spreading the perovskite layer on the surface of the SAM layer, which is often seen in NiOx-free inverse wide-bandgap perovskite solar cell systems, by modifying the hole transport layer at a low cost. The principle is that the added PbI2 and FAI are evenly distributed in the SAM layer. On the one hand, they provide binding sites for the perovskite layer, assisting the spreading of the perovskite solution. On the other hand, there is a strong interaction between FAI and PbI2, which is conducive to the uniform film formation of the perovskite layer. Through this method, the wettability of the perovskite solution can be effectively improved, the spreading of the perovskite solution can be assisted, and the quality and performance of the perovskite film can be improved. The present invention can accelerate the commercial application of tandem solar cells with wide-bandgap perovskite solar cells as bottom cells, and promote continuous breakthroughs in the efficiency of tandem cells.

[0048] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. However, the protection scope of the present invention is not limited to the following embodiment.

[0049] Comparative Example 1:

[0050] The preparation process and steps of a wide bandgap perovskite solar cell in this comparative example are as follows:

[0051] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0052] (2) Preparation of hole transport layer: Me-4PACz was dissolved in anhydrous ethanol at a concentration of 0.5 mg / mL and ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0053] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0054] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0055] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0056] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0057] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0058] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0059] Steps (1) to (8) are a conventional two-step method for preparing an inverse wide-bandgap perovskite solar cell.

[0060] Comparative Example 2:

[0061] The preparation process and steps of a wide bandgap perovskite solar cell in this comparative example are as follows:

[0062] (1) Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60 ° C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone device for 15 min.

[0063] (2) Preparation of hole transport layer: Me-4PACz was dissolved in anhydrous ethanol at a concentration of 0.5 mg / mL and ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0064] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0065] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0066] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0067] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0068] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0069] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the FTO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0070] Steps (1) to (8) are a conventional two-step method for preparing an inverse wide-bandgap perovskite solar cell.

[0071] Example 1:

[0072] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0073] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0074] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:10:10, where the concentration of Me-4PACz was 0.5 mg / mL and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0075] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0076] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0077] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0078] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0079] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0080] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0081] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0082] Example 2:

[0083] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0084] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0085] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:5:10, where the concentration of Me-4PACz was 0.5 mg / mL and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0086] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0087] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0088] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0089] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0090] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0091] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0092] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0093] Example 3:

[0094] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0095] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0096] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:5:5, where the concentration of Me-4PACz was 0.5 mg / mL and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0097] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0098] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0099] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0100] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0101] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0102] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0103] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0104] Example 4:

[0105] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0106] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0107] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:7:6. The concentration of Me-4PACz was 0.5 mg / mL, and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater, and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0108] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0109] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0110] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0111] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0112] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0113] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0114] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0115] Example 5:

[0116] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0117] (1) Select an ITO substrate of 1.5 cm × 1.5 cm and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60°C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone chamber for 15 min.

[0118] (2) Preparation of hole transport layer: Me-4PACz and PbI2 were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:10, where the concentration of Me-4PACz was 0.5 mg / mL and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0119] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0120] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0121] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0122] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0123] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0124] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0125] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0126] Example 6:

[0127] A wide bandgap perovskite solar cell according to this embodiment is prepared in the following process and steps:

[0128] (1) Select a 1.5 cm × 1.5 cm FTO substrate and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Place it in a 60 ° C oven for drying. Then place the cleaned conductive glass substrate in a UV-ozone device for 15 min.

[0129] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:7:6. The concentration of Me-4PACz was 0.5 mg / mL, and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater, and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0130] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0131] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0132] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0133] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0134] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0135] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the FTO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0136] The preparation method of steps (1)-(8) is used to prepare a two-step wide-bandgap inverse perovskite solar cell after a low-cost modified hole transport layer.

[0137] Example 7:

[0138] This embodiment provides a flexible wide-bandgap inverse perovskite solar cell fabricated using a modified SAM method using a 1.5 cm × 1.5 cm flexible substrate as a conductive base. The fabrication process and steps are as follows:

[0139] (1) A 1.5 cm × 1.5 cm flexible substrate was selected and placed in a UV-ozone chamber for 15 min to improve the surface contact between the electron transport layer and the glass substrate.

[0140] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:7:6. The concentration of Me-4PACz was 0.5 mg / mL, and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated flexible substrate was placed on a spin coater, and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0141] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped on the flexible substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0142] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0143] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0144] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0145] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0146] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the flexible substrate at a rate of 0.5 Å / s as the back electrode.

[0147] The preparation method of steps (1)-(8) can produce a large-area wide-bandgap inverted flexible perovskite solar cell with a low-cost modified hole transport layer.

[0148] Example 8:

[0149] This example provides a method for fabricating a large-area wide-bandgap inverse perovskite solar cell using an ITO (5 cm × 5 cm) conductive glass substrate using a modified SAM method. The fabrication process and steps are as follows:

[0150] (1) Select a 5 cm × 5 cm ITO substrate and place it in detergent, deionized water, isopropyl alcohol, and anhydrous ethanol in turn for 15 min of ultrasonic treatment. Then place it in a 60 ° C oven for drying. Then, place the cleaned conductive glass substrate in a UV-ozone device for 15 min to improve the surface contact between the electron transport layer and the glass substrate.

[0151] (2) Preparation of hole transport layer: Me-4PACz, PbI2, and FAI were dissolved in a mixture of anhydrous ethanol (EtOH) and dimethyl sulfoxide (DMSO) at a ratio of 1:7:6. The concentration of Me-4PACz was 0.5 mg / mL, and the ratio of EtOH:DMSO was 10:1. The mixture was ultrasonically treated for 1 h. The ozone-treated transparent conductive substrate was placed on a spin coater, and 90 μL of SAM solution was added at a time. The spin coater speed was adjusted to 3000 rpm, and the SAM layer was prepared by static spin coating. After spin coating, the substrate was annealed on a heating plate at 100°C for 10 min to obtain the hole transport layer.

[0152] (3) Based on the previous step, a wide bandgap perovskite film was prepared by two-step spin coating, and precursor solution A and precursor solution B were prepared respectively. 553 mg of PbI2 and 34.8 mg of CsI were dissolved in DMF and DMSO (DMF:DMSO=4:1) to prepare precursor solution A, and 34.9 mg of FABr and 16.0 mg of MABr were dissolved in 1 mL of isopropyl alcohol (IPA) to prepare precursor solution B. First, 100 μL of precursor solution A was dropped onto the ITO conductive substrate, and then 100 μL of precursor solution B was added to prepare the wide bandgap perovskite film.

[0153] (4) The spin-coated wet film was placed on a hot plate at 100°C and annealed for 20 min to obtain a wide bandgap perovskite film with a thickness of approximately 350 nm.

[0154] (5) A passivation layer was spin-coated on the prepared perovskite film. The passivation agent was PEAI, 0.5 mg / mL dissolved in isopropyl alcohol (IPA), with a spin-coating speed of 5000 rpm and a spin-coating time of 30 s. The film was then annealed on a hot plate at 100°C for 10 min.

[0155] (6) Prepare PCBM as an electron transport layer using spin coating technology. Dissolve PCBM in chlorobenzene (CB) at a concentration of 20 mg / mL and shake overnight. Place the passivated perovskite film prepared above on a spin coater. Set the spin coater speed program to 3000 rpm, acceleration to 1500 rpm / s, and spin coating time to 30 s. Use a pipette to weigh 80 μL of PCBM solution and dynamically spin coat the solution on the perovskite film to prepare an electron transport layer with a thickness of approximately 100 nm.

[0156] (7) The BCP layer was prepared using spin coating technology. BCP was dissolved in isopropyl alcohol (IPA) to prepare a solution with a concentration of 0.5 mg / mL. The solution was stirred overnight. The speed of the gel spinner was set to 6000 rpm, the acceleration was 5000 rpm / s, and the spin coating time was 30 s. 110 μL of BCP solution was weighed using a pipette and the BCP layer was prepared by static spin coating.

[0157] (8) Using an evaporator, a layer of metal Ag with a thickness of 100 nm was evaporated on the ITO conductive substrate at a rate of 0.5 Å / s as the back electrode.

[0158] The preparation method of steps (1)-(8) can produce a large-area wide-bandgap inverse perovskite solar cell after low-cost modification of the hole transport layer.

[0159] Test results:

[0160] The performance of the solar cells prepared in the above comparative examples and embodiments was tested under standard test conditions (AM 1.5G, 25°C, 100 Mw / cm 2 ), and tested its open circuit voltage, short circuit current, fill factor, and cell conversion efficiency photovoltaic performance parameters. The test results are shown in Table 1.

[0161]

[0162] As shown in Table 1, the open circuit voltage, short circuit current, and fill factor of the wide-bandgap perovskite solar cell after the low-cost modified hole transport layer are significantly improved. In Example 4, under the optimal ratio of SAM, PbI2, and FAI, the resulting device has a photoelectric conversion efficiency of up to 22.02%.

[0163] Figure 1 Schematic diagram of the structure of the wide-bandgap perovskite solar cell prepared according to the present invention.

[0164] Figure 2 Schematic diagram of the structure of the flexible wide-bandgap perovskite solar cell prepared according to the patent of this invention.

[0165] Figure 3 This is the EQE diagram of the wide-bandgap perovskite film prepared according to the present invention. Data analysis shows that the bandgap width of the perovskite film is about 1.66 eV.

[0166] Figure 4 Coverage of perovskite films in perovskite solar cells prepared with unmodified SAM and modified SAM. Figure 3It shows that the perovskite film of the modified SAM (b) is almost completely spread on the conductive substrate, while the perovskite film of the unmodified SAM (a) is only spread on the ITO surface of the conductive substrate and not at all on the glass surface. This situation will cause the concentration of the perovskite solution at various positions on the substrate during the spin coating process to be uneven, thereby affecting the quality of the prepared film.

[0167] Figure 5 SEM images of perovskite films in perovskite solar cells prepared with unmodified SAM and modified SAM. Figure 4 The perovskite film with modified SAM (b) exhibits a smooth, dense structure with blurred grain boundaries and large grains, while the unmodified SAM (a) film exhibits uneven grain size, varying heights, and contains voids. Voids can form leakage channels, while grain boundary defects can hinder carrier transport, significantly degrading device performance.

[0168] Figure 6 This is an SEM image of the interface thickness of the perovskite film prepared in the patent of this invention. Figure 6 It shows that the cross-sectional thickness of the wide-bandgap perovskite film prepared by the two-step method in the present invention is about 480 nm.

[0169] Figure 7 JV curves of wide bandgap perovskite solar cells prepared with modified SAM and unmodified SAM. Figure 7 It shows that the open circuit voltage and current density of the battery are greatly improved after the modified SAM.

[0170] Figure 8 Figure 1 shows the stability of wide-bandgap perovskite solar cells made with the modified and unmodified SAMs under continuous illumination at 1.5G AM sunlight. After 30 days of continuous operation, the PCE of the cell made with the modified SAM still maintained approximately 80% of its initial efficiency, while the PCE of the unmodified cell declined to below 65%.

[0171] This proves that the hole transport layer modification and optimization method proposed in the present invention has a significant improvement in the photoelectric conversion efficiency and stability of wide-bandgap perovskite solar cells.

[0172] Obviously, the above embodiments are merely examples for clarification and are not intended to limit the implementation methods. Any person skilled in the art may utilize the technical content disclosed above to modify or modify the above embodiments into equivalent embodiments with equivalent variations. However, any simple modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention remain within the scope of protection of the technical solution of the present invention.

Claims

1. A method for optimizing the performance of perovskite solar cells by modifying the hole transport layer, characterized in that: When preparing the hole transport layer, additives are added to the SAM solution to prepare a modified SAM layer, and then the perovskite layer is prepared on the SAM layer by a two-step spin coating method; The additives are PbI2 and FAI.

2. The method according to claim 1, wherein: The perovskite solar cell is a pin type, and its structure from bottom to top includes a transparent conductive substrate, a p-type hole transport layer, a wide bandgap perovskite light absorption layer, an n-type electron transport layer and a metal electrode; The p-type hole transport layer is selected from one or more p-type semiconductor materials of polystyrene sulfonate, poly [bis (4-phenyl) (2,4,6-trimethylphenyl) amine], redox graphene, [4- (3,6-dimethyl-9H-carbazol-9-yl) butyl] phosphoric acid, (2- (3,6-dimethyl-9H-carbazol-9-yl) ethyl) phosphonic acid, and 4-butyl-N,N-diphenylaniline homopolymer.

3. The method according to claim 1 or 2, characterized in that: The SAM molecules contained in the SAM solution are Me-4PACz or Me-2PACz, and the solution concentration is 0.5 mg / mL.

4. The method according to claim 3, wherein: The mass ratio of SAM molecules, PbI2 and FAI is 1:5-10:5-10.

5. The method according to claim 4, characterized in that: The hole transport layer is prepared on the pretreated transparent conductive substrate by spin coating. First, a SAM solution is prepared and an additive is added to obtain a modified SAM mother solution. Place the pretreated transparent conductive substrate on a spin coater, add 80 μL of modified SAM mother solution each time, and adjust the spin coater speed to ensure the formation of a dense and appropriately thick SAM layer. After spin coating, anneal at 100-120°C for 10 min to finally obtain a hole transport layer.

6. The method according to claim 5, characterized in that: The spin coating speed is 3000-4000 rpm and the working time is 25-35 s.

7. The method according to claim 5, characterized in that: PbI2 and CsI were dissolved in DMF and DMSO to prepare precursor solution A; FABr and MABr were dissolved in isopropanol to prepare precursor solution B; the precursor solution A was first added dropwise onto the prepared hole transport layer, and then the precursor solution B was added dropwise, and a wide bandgap perovskite film was prepared after annealing.

8. The method according to claim 7, wherein: The spin coating speed of the precursor solution A is 3000 rpm, the spin coating time is 30 s, and the spin coating acceleration is 2000 rpm / s; the spin coating speed of the precursor solution B is 3500 rpm, the spin coating time is 30 s, and the spin coating acceleration is 2000 rpm / s.

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