Solar cell based on 4-phosphate butyric acid perovskite additive and preparation method thereof

Abstract

The invention discloses a solar cell based on a 4-phosphate butyric acid perovskite additive and a preparation method thereof, and relates to the technical field of solar cells. The cell structure comprises a substrate, a first functional layer, a perovskite layer, a second functional layer, a transparent conductive layer and a metal electrode layer which are sequentially stacked from bottom to top, if the first functional layer is a hole transport layer, the second functional layer is an electron transport layer; if the first functional layer is an electron transport layer, the second functional layer is a hole transport layer. A buffer layer is arranged between the second functional layer and the transparent conductive layer in the laminated cell structure; a perovskite additive with a certain concentration is deposited in the perovskite absorption layer, the molecules of the perovskite additive are 4-phosphoric acid butyric acid, and the concentration of an organic solution of the 4-phosphoric acid butyric acid is 0.1-5.0 mg / mL. The 4-phosphobutyric acid is used as an additive material to be applied to the perovskite layer prepared by the evaporation two-step method, so that the crystal quality of perovskite can be effectively improved, and the photoelectric conversion efficiency and the stability of the solar cell are improved.

Description

Technical Field

[0001] The present invention belongs to the field of new energy, and specifically relates to a method for preparing a wide-bandgap perovskite solar cell using an evaporation / solution two-step method based on a 4-phosphobutyric acid additive. Background Art

[0002] With the increasing use of fossil fuels, the environmental problems facing mankind are becoming increasingly prominent. Solar energy resources can continue to last for 60 billion years, which is inexhaustible for the existence of mankind. The excellent photoelectric conversion efficiency and low manufacturing cost of perovskite have made it one of the research hotspots that have attracted much attention. The perovskite film prepared by the evaporation / solution two-step method has the advantages of good crystallization quality, low defect density, and good uniformity, which can effectively improve the conversion efficiency and stability of perovskite solar cells. In addition, this method has the advantages of simple preparation process, low cost, and large-area preparation, and has good prospects for industrial application. However, there is a large gap between the photoelectric conversion efficiency (PCE) of the wide-bandgap perovskite solar cell prepared by the evaporation / solution two-step method and the wide-bandgap perovskite solar cell prepared by the one-step method. One of the key factors is the large opening voltage loss of the wide-bandgap perovskite cell, which is mainly attributed to the following aspects:

[0003] 1. High defect density: Defects such as lead halide vacancies and interstitial atoms are easily formed in perovskite crystals. These defects act as non-radiative recombination centers, significantly reducing the carrier lifetime and leading to voltage loss.

[0004] 2. Interface recombination: The interface energy level mismatch between the perovskite and the charge transport layer or the high interface state density causes carriers to recombine at the interface instead of being effectively extracted.

[0005] 3. Band structure limitations: Perovskites have a wide band gap, but the actual open-circuit voltage is affected by non-ideal factors and cannot reach the theoretical limit. In addition, non-ideal band alignment may lead to low charge extraction efficiency.

[0006] Furthermore, wide-bandgap perovskite films also present challenges. During the annealing process, the large difference in thermal expansion coefficients between the substrate and the perovskite leads to compressive stress in the perovskite. This stress can cause lattice distortion and defects, accelerating the decomposition of the perovskite. This can also lead to degradation of solar cells under high humidity conditions.

[0007] In summary, the main problems of existing wide-bandgap perovskite solar cells are severe open-circuit voltage loss and poor stability. Summary of the Invention

[0008] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a method for preparing wide-bandgap perovskite solar cells using an evaporation / solution two-step process based on a 4-phosphobutyric acid additive.

[0009] To achieve the purpose of the present invention, it is proposed to add 4-phosphobutyric acid to an organic salt solution and spin-coat it on the surface of an inorganic precursor film, and then prepare a wide-bandgap perovskite film after high-temperature annealing. The phosphoric acid and carboxylic acid groups inside the 4-phosphobutyric acid will interact with the uncoordinated lead ions inside the perovskite film, reducing the defect density at the grain boundaries inside the film and inhibiting the non-radiative recombination of carriers; regulating the band structure at the I / N interface, promoting the transport and transfer of photogenerated carriers; and supplementing the anchoring of the self-assembled monolayer. Due to the squeezing effect of the perovskite crystal, some 4-phosphobutyric acid molecules migrate to the P / I interface, and the phosphate groups inside the molecules interact with ITO or NiO. X The hydroxyl groups on the film undergo dehydration and condensation, spontaneously anchoring to the vacancies in the self-assembled monolayer, improving the P / I interface. This synergistic effect allows the battery to achieve a higher open-circuit voltage.

[0010] The technical solution of the present invention is:

[0011] The purpose of the first aspect is that the present invention provides a solar cell based on a 4-phosphobutyric acid perovskite additive, characterized in that the structure of the perovskite solar cell is stacked from bottom to top as follows: a substrate, a first functional layer, a perovskite absorption layer, a second functional layer, a transparent electrode and a metal electrode layer. If the first functional layer is a hole transport layer, the second functional layer is an electron transport layer; if the first functional layer is an electron transport layer, the second functional layer is a hole transport layer; there is a buffer layer between the second functional layer and the transparent conductive layer in the stacked cell structure; a certain concentration of perovskite additive is deposited in the perovskite absorption layer, the perovskite additive molecule is 4-phosphobutyric acid, and the concentration of the organic solution of 4-phosphobutyric acid is 0.1 to 5.0 mg / mL.

[0012] Furthermore, the band gap of the perovskite of the present invention is a band gap between 1.51 eV and 1.80 eV.

[0013] The second aspect of the present invention provides a method for preparing a solar cell based on a 4-phosphate butyric acid perovskite additive, which is a method for preparing a perovskite solar cell based on a 4-phosphate butyric acid additive using an evaporation / solution two-step method, the method comprising:

[0014] (1) cleaning the transparent conductive substrate and preparing a first functional layer on the transparent conductive substrate;

[0015] (2) A 200 nm inorganic precursor film was prepared by a dual-source co-evaporation process of PbX2 and CsX, where X = I, Br, Cl;

[0016] (3) spin-coating an organic salt solution containing 4-phosphobutyric acid on the inorganic precursor film, and preparing a perovskite film after high-temperature annealing;

[0017] (4) preparing a second functional layer on the upper interface passivation layer;

[0018] (5) Prepare a metal electrode on the electron transport layer.

[0019] In the present invention, the first functional layer and the second functional layer are either hole transport layers or electron transport layers. That is, if the first functional layer is a hole transport layer, the second functional layer is an electron transport layer; if the first functional layer is an electron transport layer, the second functional layer is a hole transport layer.

[0020] Furthermore, the transparent conductive substrate in step (1) of the present invention is one of FTO and ITO conductive glass;

[0021] The hole transport layer in step (1) is NiO x , SAM, PTAA;

[0022] The perovskite precursor solution solvent in step (2) is isopropanol, and the solutes are FAI, FABr and MACl; the concentration of the solutes is 0.6 to 0.8 mol / L;

[0023] The inorganic precursor film described in step (2) is prepared by co-evaporation of PbI2 and CsBr, and the evaporation rates are The evaporation thickness is 200nm;

[0024] The solvent of the 4-phosphobutyric acid solution in step (3) is one or a combination of isopropanol, ethanol or propanol, and the concentration is 0.5 to 1.0 mg / mL.

[0025] The perovskite absorption layer described in step (3) is prepared by spin coating an organic salt solution onto an inorganic precursor film and then annealing, the spin coating speed is 3000-5000 rpm / min, and the time is 90-110 seconds; the annealing condition is annealing at 140-150°C for 15-20 minutes in ambient air with a humidity of 30-40%;

[0026] The electron transport layer in step (4) is PCBM, SnO2, C 60 One of the following;

[0027] The metal electrode described in step (5) is one of silver, copper and gold electrodes deposited with a thickness of 80 to 100 nm by vacuum evaporation.

[0028] In a third aspect, the present invention provides a use of a 4-phosphate butyrate perovskite, which is suitable for the following structural devices:

[0029] a. Perovskite single-junction solar cells prepared by the evaporation / spin coating two-step method;

[0030] b. Perovskite single-junction solar cells prepared by the two-step evaporation / blade coating method;

[0031] c. Perovskite single-junction solar cells prepared by the two-step evaporation / slit coating method;

[0032] d. Perovskite / crystalline silicon tandem solar cells.

[0033] The advantages and positive effects of the present invention are:

[0034] The core innovation of this patent lies in utilizing the unique molecular structure of 4-phosphobutyric acid to modify perovskite thin films through its multifunctional functional groups, thereby significantly improving the performance and stability of perovskite solar cells. The following is a detailed explanation of the key points and technical details of this patent:

[0035] 1. Passivation of internal defects in perovskite films. 4-Phosphobutyric acid can passivate the under-coordinated Pb in perovskite. 2+ Lewis acid-base reaction occurs, forming an interaction. This interaction improves the perovskite crystal quality while passivating defect sites at the grain boundaries after the perovskite film is formed. This synergistic effect reduces the defect density inside the perovskite film, inhibits the non-radiative recombination of photogenerated carriers inside the film, and improves the V of the solar cell. OC and FF.

[0036] 2. Supplementary anchoring of the self-assembled monolayer. Due to the squeezing effect during the perovskite crystallization process, the 4-phosphobutyric acid molecules migrate to the lower interface of the perovskite film. At this lower interface, some 4-phosphobutyric acid molecules react with vacancies in the self-assembled layer under high temperature conditions. At this point, the phosphate groups within the 4-phosphobutyric acid molecules dehydrate and condense with the hydroxyl groups on the ITO surface, thereby supplementing the anchoring of the self-assembled monolayer.

[0037] 3. Modulating the I / N interface band structure: The introduction of 4-phosphobutyric acid makes the film band structure more n-type. At the I / N interface, a more n-type band structure on the film surface facilitates carrier transfer across the I / N interface, reducing the open-circuit voltage loss of the solar cell.

[0038] 4. Improved photoelectric conversion efficiency: After the introduction of 4-phosphobutyric acid, the internal defects of the perovskite film grain boundaries are passivated, the P / I interface contact is improved, and the I / N interface band structure is regulated. The three work synergistically. This molecule significantly reduces and optimizes the carrier transport and separation efficiency, thereby greatly improving the photoelectric conversion efficiency of the battery.

[0039] This patented technology is not only applicable to wide-bandgap perovskite solar cells, but is also effective in perovskite / crystalline silicon tandem solar cells. It can also be extended to other perovskite optoelectronic devices, such as perovskite light-emitting diodes (PeLEDs) and perovskite photodetectors. The technology's low cost and high efficiency make it promising for large-scale commercial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the structure of a perovskite solar cell based on a comparative example of the present invention without 4-phosphobutyric acid molecular additive modification;

[0041] Figure 2 Schematic diagram of the structure of a perovskite solar cell with a 4-phosphobutyric acid molecular additive according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic flow chart of a method for preparing a perovskite-based solar cell according to the present invention;

[0043] Figure 4 This is a graph showing the volt-ampere characteristic of a wide-bandgap perovskite solar cell based on the introduction of a 4-phosphobutyric acid molecular additive at a concentration of 0.5 mg / mL according to Example 1 of the present invention;

[0044] Figure 5 This is a graph showing the volt-ampere characteristic of a wide-bandgap perovskite solar cell based on the introduction of a 4-phosphobutyric acid molecular additive at a concentration of 0.75 mg / mL according to Example 2 of the present invention;

[0045] Figure 6 This is a graph showing the volt-ampere characteristic of a wide-bandgap perovskite solar cell based on the introduction of a 4-phosphobutyric acid molecular additive at a concentration of 1 mg / mL according to Example 3 of the present invention;

[0046] Figure 7 This is a volt-ampere characteristic curve of a wide-bandgap perovskite solar cell without the introduction of 4-phosphobutyric acid molecular additive in the comparative example of the present invention; DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] This invention provides a method for preparing a wide-bandgap perovskite solar cell based on the introduction of 4-phosphobutyric acid. 4-phosphobutyric acid is used to passivate internal defects in the perovskite film, improve the P / I interface contact, and regulate the I / N interface band structure, effectively improving the efficiency and stability of the perovskite solar cell. The cell structure, stacked from bottom to top, consists of a transparent conductive substrate, a hole transport layer, a perovskite absorption layer, an upper interface passivation layer, an electron transport layer, and a metal electrode.

[0049] Example 1:

[0050] The present invention provides a method for preparing a wide-bandgap perovskite solar cell using a two-step evaporation / solution method based on a 4-phosphobutyric acid additive, comprising the following steps:

[0051] 1. Place the ITO conductive glass substrate (2×2cm 2 ) ultrasonically cleaning the substrate with detergent, deionized water, and isopropyl alcohol for 15 to 20 minutes, drying the substrate with nitrogen, and treating the substrate with ultraviolet ozone for 20 to 30 minutes to obtain a clean and well-wettable ITO conductive glass substrate;

[0052] 2. Add 10-30 mg of NiO x The powder was added to 1 mL of deionized water to obtain 10-30 mg / mL of NiO. x colloidal solutions;

[0053] 3. Take NiO from step 2 x The colloidal solution is spin-coated on the ITO conductive glass substrate prepared in step 1 at a rotation speed of 2000-3000 rpm / min for 20-30 seconds; thereafter, the colloidal solution is annealed in ambient air at 100-130° C. for 15-30 minutes to obtain a nickel oxide thin film.

[0054] 4. Dissolve an appropriate amount of Me-4PACz in isopropanol. Heat and stir in a nitrogen atmosphere until completely dissolved, obtaining a 1.5 mol / L Me-4PACz solution. Spin-coat the solution onto the nickel oxide film obtained in step 3 at a speed of 5000 rpm / min for 60 seconds. Anneal at 150°C in a nitrogen atmosphere for 10-15 minutes to obtain a hole transport layer.

[0055] 5. The hole transport layer substrate obtained in step 4 was transferred to a vacuum chamber and co-evaporated using PbI2 and CsBr dual sources at evaporation rates of and The inorganic precursor film was prepared by evaporation with a thickness of 200 nm;

[0056] 6. Dissolve FAI and FABr in isopropanol at a molar ratio of 1:1. Then, heat and stir in a nitrogen atmosphere until completely dissolved to obtain an organic salt solution with a concentration of 0.6-0.8 mol / L.

[0057] 7. Add 0.5 mg of 4-phosphobutyric acid to 1 mL of an organic salt solution (FAI:FABr=1:1, solvent is isopropanol) to prepare an organic salt solution doped with 4-phosphobutyric acid.

[0058] 8. Spin-coat the organic salt solution obtained in step 7 on the inorganic precursor film obtained in step 5 at a rotation speed of 3000-5000 rpm / min for 30-50 s; then anneal at 140-150°C for 15-20 min in an environment with a humidity of 30-40% to obtain a wide-bandgap perovskite film with a thickness of 400-500 nm.

[0059] 9. Use evaporation method to deposit 20nm thick C on the perovskite film obtained in step 8 60 thin film to obtain an electron transport layer;

[0060] 10. Evaporate a silver film with a thickness of 80 to 100 nm on the electron transport layer in step 9 to obtain a wide bandgap perovskite solar cell.

[0061] Experimental results: Conduct performance tests on solar cells, such as Figure 4 As shown, at AM1.5, 100mW / cm 2 Under standard light intensity, the open circuit voltage of the solar cell prepared in this embodiment is 1.145V and the short circuit current density is 20.43mA / cm 2 , filling factor 81.89% and efficiency 19.13%.

[0062] Example 2:

[0063] The present invention provides a method for preparing a wide-bandgap perovskite solar cell using a two-step evaporation / solution method based on a 4-phosphobutyric acid additive, comprising the following steps:

[0064] 1. Place the ITO conductive glass substrate (2×2cm 2 ) ultrasonically cleaning the substrate with detergent, deionized water, and isopropyl alcohol for 15 to 20 minutes, drying the substrate with nitrogen, and treating the substrate with ultraviolet ozone for 20 to 30 minutes to obtain a clean and well-wettable ITO conductive glass substrate;

[0065] 2. Add 10-30 mg of NiO x The powder was added to 1 mL of deionized water to obtain 10-30 mg / mL of NiO. x colloidal solutions;

[0066] 3. Take NiO from step 2 x The colloidal solution is spin-coated on the ITO conductive glass substrate prepared in step 1 at a rotation speed of 2000-3000 rpm / min for 20-30 seconds; thereafter, the colloidal solution is annealed in ambient air at 100-130° C. for 15-30 minutes to obtain a nickel oxide thin film.

[0067] 4. Dissolve an appropriate amount of Me-4PACz in isopropanol. Heat and stir in a nitrogen atmosphere until completely dissolved, obtaining a 1.5 mol / L Me-4PACz solution. Spin-coat the solution onto the nickel oxide film obtained in step 3 at a speed of 5000 rpm / min for 60 seconds. Anneal at 150°C in a nitrogen atmosphere for 10-15 minutes to obtain a hole transport layer.

[0068] 5. The hole transport layer substrate obtained in step 4 was transferred to a vacuum chamber and co-evaporated using PbI2 and CsBr dual sources at evaporation rates of and The inorganic precursor film was prepared by evaporation with a thickness of 200 nm;

[0069] 6. Dissolve FAI and FABr in isopropanol at a molar ratio of 1:1. Then, heat and stir in a nitrogen atmosphere until completely dissolved to obtain an organic salt solution with a concentration of 0.6-0.8 mol / L.

[0070] 7. Add 0.75 mg of 4-phosphobutyric acid to 1 mL of an organic salt solution (FAI:FABr=1:1, solvent: isopropanol) to prepare an organic salt solution doped with 4-phosphobutyric acid.

[0071] 8. Spin-coat the organic salt solution obtained in step 7 on the inorganic precursor film obtained in step 5 at a rotation speed of 3000-5000 rpm / min for 30-50 s; then anneal at 140-150°C for 15-20 min in an environment with a humidity of 30-40% to obtain a wide-bandgap perovskite film with a thickness of 400-500 nm.

[0072] 9. Use evaporation method to deposit 20nm thick C on the perovskite film obtained in step 8 60 thin film to obtain an electron transport layer;

[0073] 10. Evaporate a silver film with a thickness of 80 to 100 nm on the electron transport layer in step 9 to obtain a wide bandgap perovskite solar cell.

[0074] Experimental results: Conduct performance tests on solar cells, such as Figure 4 As shown, at AM1.5, 100mW / cm 2 Under standard light intensity, the open circuit voltage of the solar cell prepared in this embodiment is 1.203V and the short circuit current density is 20.76mA / cm 2 , fill factor 84.22% and efficiency 21.05%.

[0075] Example 3:

[0076] The present invention provides a method for preparing a wide-bandgap perovskite solar cell using a two-step evaporation / solution method based on a 4-phosphobutyric acid additive, comprising the following steps:

[0077] 1. Place the ITO conductive glass substrate (2×2cm 2 ) ultrasonically cleaning the substrate with detergent, deionized water, and isopropyl alcohol for 15 to 20 minutes, drying the substrate with nitrogen, and treating the substrate with ultraviolet ozone for 20 to 30 minutes to obtain a clean and well-wettable ITO conductive glass substrate;

[0078] 2. Add 10-30 mg of NiO x The powder was added to 1 mL of deionized water to obtain 10-30 mg / mL of NiO. x colloidal solutions;

[0079] 3. Take NiO from step 2 x The colloidal solution is spin-coated on the ITO conductive glass substrate prepared in step 1 at a rotation speed of 2000-3000 rpm / min for 20-30 seconds; thereafter, the colloidal solution is annealed in ambient air at 100-130° C. for 15-30 minutes to obtain a nickel oxide thin film.

[0080] 4. Dissolve an appropriate amount of Me-4PACz in isopropanol. Heat and stir in a nitrogen atmosphere until completely dissolved, obtaining a 1.5 mol / L Me-4PACz solution. Spin-coat the solution onto the nickel oxide film obtained in step 3 at a speed of 5000 rpm / min for 60 seconds. Anneal at 150°C in a nitrogen atmosphere for 10-15 minutes to obtain a hole transport layer.

[0081] 5. The hole transport layer substrate obtained in step 4 was transferred to a vacuum chamber and co-evaporated using PbI2 and CsBr dual sources at evaporation rates of and The inorganic precursor film was prepared by evaporation with a thickness of 200 nm;

[0082] 6. Dissolve FAI and FABr in isopropanol at a molar ratio of 1:1. Then, heat and stir in a nitrogen atmosphere until completely dissolved to obtain an organic salt solution with a concentration of 0.6-0.8 mol / L.

[0083] 7. Add 1 mg of 4-phosphobutyric acid to 1 mL of an organic salt solution (FAI:FABr=1:1, solvent: isopropanol) to prepare an organic salt solution doped with 4-phosphobutyric acid.

[0084] 8. Spin-coat the organic salt solution obtained in step 7 on the inorganic precursor film obtained in step 5 at a rotation speed of 3000-5000 rpm / min for 30-50 s; then anneal at 140-150°C for 15-20 min in an environment with a humidity of 30-40% to obtain a wide-bandgap perovskite film with a thickness of 400-500 nm.

[0085] 9. Use evaporation method to deposit 20nm thick C on the perovskite film obtained in step 8 60 thin film to obtain an electron transport layer;

[0086] 10. Evaporate a silver film with a thickness of 80 to 100 nm on the electron transport layer in step 9 to obtain a wide bandgap perovskite solar cell.

[0087] Experimental results: Conduct performance tests on solar cells, such as Figure 4 As shown, at AM1.5, 100mW / cm 2 Under standard light intensity, the open circuit voltage of the solar cell prepared in this embodiment is 1.199V and the short circuit current density is 20.43mA / cm 2 , fill factor 80.42% and efficiency 19.71%.

[0088] Comparative Example:

[0089] The present invention provides a method for preparing a wide-bandgap perovskite solar cell containing 4-phosphobutyric acid without an additive, comprising the following steps:

[0090] 1. Place the ITO conductive glass substrate (2×2cm 2 ) ultrasonically cleaning the substrate with detergent, deionized water, and isopropyl alcohol for 15 to 20 minutes, drying the substrate with nitrogen, and treating the substrate with ultraviolet ozone for 20 to 30 minutes to obtain a clean and well-wettable ITO conductive glass substrate;

[0091] 2. Add 10-30 mg of NiO x The powder was added to 1 mL of deionized water to obtain 10-30 mg / mL of NiO. x colloidal solutions;

[0092] 3. Take NiO from step 2 x The colloidal solution is spin-coated on the ITO conductive glass substrate prepared in step 1 at a rotation speed of 2000-3000 rpm / min for 20-30 seconds; thereafter, the colloidal solution is annealed in ambient air at 100-130° C. for 15-30 minutes to obtain a nickel oxide thin film.

[0093] 4. Dissolve an appropriate amount of Me-4PACz in isopropanol. Heat and stir in a nitrogen atmosphere until completely dissolved, obtaining a 1.5 mol / L Me-4PACz solution. Spin-coat the solution onto the nickel oxide film obtained in step 3 at a speed of 5000 rpm / min for 60 seconds. Anneal at 150°C in a nitrogen atmosphere for 10-15 minutes to obtain a hole transport layer.

[0094] 5. The hole transport layer substrate obtained in step 4 was transferred to a vacuum chamber and co-evaporated using PbI2 and CsBr dual sources at evaporation rates of and The inorganic precursor film was prepared by evaporation with a thickness of 200 nm;

[0095] 6. Dissolve FAI and FABr in isopropanol at a molar ratio of 1:1. Then, heat and stir in a nitrogen atmosphere until completely dissolved to obtain an organic salt solution with a concentration of 0.6-0.8 mol / L.

[0096] 7. Spin-coat the organic salt solution obtained in step 6 on the inorganic precursor film obtained in step 5 at a rotation speed of 3000-5000 rpm / min for 30-50 s; then anneal at 140-150°C for 15-20 min in an environment with a humidity of 30-40% to obtain a wide-bandgap perovskite film with a thickness of 400-500 nm.

[0097] 8. Use evaporation method to deposit 20nm thick C on the perovskite film obtained in step 7 60 thin film to obtain an electron transport layer;

[0098] 9. Evaporate a silver film with a thickness of 80 to 100 nm on the electron transport layer in step 8 to obtain a wide bandgap perovskite solar cell.

[0099] The difference from Examples 1-3 is that this comparative example does not introduce 4-phosphobutyric acid molecular additive. Experimental results: The performance test of the solar cell is carried out. Figure 7 As shown, at AM1.5, 100mW / cm 2 Under standard light intensity, the open circuit voltage of the solar cell prepared in this embodiment is 1.143V and the short circuit current density is 20.20mA / cm 2 , fill factor 78.26% and efficiency 18.08%.

[0100] In summary, a method for preparing wide-bandgap perovskite solar cells using a two-step evaporation / solution method with a 4-phosphobutyric acid additive is provided. The 4-phosphobutyric acid additive is added to an organic salt solution, spin-coated onto an inorganic precursor film, and annealed to produce a perovskite film. During the annealing process, due to the crystallization of the perovskite, some of the phosphate and carboxylic acid groups in the 4-phosphobutyric acid interact with the perovskite. Some of the 4-phosphobutyric acid molecules also interact with the P / I interface, providing additional anchoring for the self-assembled monolayer and improving interfacial contact. Ultimately, efficient and stable single-cell perovskite solar cells and tandem solar cells are obtained.

[0101] The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and the embodiments shown do not cover all options of the technical solutions of the present invention. For example, in the embodiment, the hole transport layer is made of NiO. x In addition to SAM and PTAA, the electron transport layer can also be selected. In addition to PCBM, C 60 , SnO2; in step 5, the dual-source co-evaporation is not limited to PbI2 and CsBr, and can be arbitrarily selected from PbX2 and CsX (X = I, Br, Cl). Any of the above-mentioned selected embodiments can achieve the objectives of the present invention and achieve the technical effects of the present invention. It should be understood that any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A solar cell based on 4-phosphobutyrate perovskite additive, characterized in that: The structure of the perovskite solar cell is stacked from bottom to top as follows: a substrate, a first functional layer, a perovskite absorption layer, a second functional layer, a transparent electrode and a metal electrode layer. If the first functional layer is a hole transport layer, the second functional layer is an electron transport layer; if the first functional layer is an electron transport layer, the second functional layer is a hole transport layer; a buffer layer is provided between the second functional layer and the transparent conductive layer in the stacked cell structure; a certain concentration of a perovskite additive is deposited on the perovskite absorption layer, the perovskite additive molecule being 4-phosphobutyric acid, and the organic solution concentration of 4-phosphobutyric acid is 0.1 to 5.0 mg / mL.

2. The solar cell based on 4-phosphobutyrate perovskite additive according to claim 1, characterized in that: The band gap of perovskite is one of 1.51eV-1.80eV.

3. A method for preparing a solar cell based on a 4-phosphobutyrate perovskite additive according to claim 1 or 2, characterized in that: The following steps are involved: (1) preparing a first functional layer on a substrate; the substrate is a silicon substrate with an intermediate connecting layer or a glass substrate with a transparent electrode; (2) first depositing an inorganic perovskite precursor film having PbX2 and CsX on the first functional layer; wherein X = I, Br, Cl; (3) depositing an organic salt containing 4-phosphobutyric acid on an inorganic perovskite precursor film, and preparing a perovskite film after high-temperature annealing; (4) preparing a second functional layer on the perovskite film; (5) sequentially preparing a transparent electrode and a metal electrode on the second functional layer; The thickness of the inorganic precursor film is 5-1000 nm, and the concentration of the organic solution of 4-phosphobutyric acid is 0.1-5.0 mg / mL.

4. The preparation method according to claim 3, wherein The inorganic precursor film described in step (2) is prepared by co-evaporation of PbI2 and CsBr, and the evaporation rates are / S, / S; the evaporation thickness is 200nm.

5. The preparation method according to claim 3, wherein The solvent of the organic salt solution in step (3) is one or a combination of isopropanol, ethanol or propanol, and the solutes are FAI, FABr and MACl; the concentration of the solutes is 0.6-0.8 mol / L.

6. The preparation method according to claim 3, wherein The perovskite film in step (3) is prepared by spin coating, scraping or slit coating an organic salt solution containing 4-phosphobutyric acid onto an inorganic precursor film and then annealing.

7. The preparation method according to claim 3, wherein In step (3), the perovskite absorption layer is prepared by spin coating an organic salt solution onto an inorganic precursor film and then annealing. The spin coating speed is 3000-5000 rpm / min and the time is 90-110s. The annealing condition is annealing at 140-150°C for 15-20min in ambient air with a humidity of 30-40%.

8. The preparation method according to claim 3, wherein The transparent electrode is one of FTO and ITO conductive glass; the first functional layer and the second functional layer are hole transport layers or electron transport layers, and the hole transport layer is NiO x , SAM, PTAA; the electron transport layer is PCBM, C 60 , SnO2; the metal electrode is one of a silver electrode, a gold electrode or a metal grid line with a thickness of 80 to 100 nm.

9. A use of the 4-phosphobutyrate perovskite according to claim 1 or 2, characterized in that: This perovskite is suitable for the following structural devices: a. Perovskite single-junction solar cells prepared by the evaporation / spin coating two-step method; b. Perovskite single-junction solar cells prepared by the two-step evaporation / blade coating method; c. Perovskite single-junction solar cells prepared by the two-step evaporation / slit coating method; d. Perovskite / crystalline silicon tandem solar cells.

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