A perovskite solar cell and its fabrication method

Abstract

This invention discloses a perovskite solar cell and its fabrication method. The perovskite solar cell of this invention comprises, from bottom to top, a conductive glass substrate, an electron transport layer, a functional layer, a passivation layer, a hole transport layer, and a metal electrode layer. The functional layer mainly consists of a perovskite light-absorbing layer I, or, from bottom to top, a monomer molecule passivation layer and a perovskite light-absorbing layer II. The perovskite light-absorbing layer I is formed by coating the electron transport layer with a precursor solution I containing monomer molecules. The monomer molecule passivation layer and the perovskite light-absorbing layer II are formed by sequentially coating the electron transport layer with a monomer molecule solution and a precursor solution II without monomer molecules. This invention significantly improves the turn-on voltage and fill factor by influencing charge transport and carrier lifetime through monomer molecules, ultimately improving the photoelectric conversion efficiency of the perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and particularly relates to a perovskite solar cell and its preparation method. Background Technology

[0002] In an era of rapid economic globalization and a dramatic increase in population, the problem of energy shortages is becoming increasingly serious. Currently, the world's main energy supply comes from the combustion of fossil fuels such as oil, natural gas, and coal. However, these are not renewable energy sources and cannot meet the future needs of humanity. Furthermore, the combustion of fossil fuels emits large amounts of carbon dioxide.

[0003] Therefore, not only is energy scarcity a pressing concern, but the development of new energy sources is also crucial for ensuring the sustainable development of human civilization. Perovskite solar cells represent the most promising next-generation clean energy source, experiencing rapid development with a current peak photoelectric conversion efficiency of 26.41%. However, the actual photoelectric conversion efficiency of perovskite solar cells still falls short of the theoretical efficiency. The main reasons include: defects in the perovskite light-absorbing layer itself, and interface defects between the light-absorbing and transport layers, leading to non-radiative recombination and significant voltage drop, thus hindering efficiency improvement. This is detrimental to photoelectric performance.

[0004] For perovskite solar cell fabrication methods, the two-step method allows for pre-conditioning of the lead iodide template, offering good operability and commercial potential. However, the growth of perovskite crystals on the lead iodide substrate and the infiltration of organic cation solutions mean that the perovskite grains are prone to disorder and the introduction of non-radiative recombination sites, affecting the photovoltaic efficiency and stability of the device. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a perovskite solar cell and its fabrication method. This invention improves the photoelectric conversion efficiency of perovskite solar cells by introducing monomer molecules.

[0006] The present invention adopts the following technical solution:

[0007] I. A type of perovskite solar cell

[0008] The perovskite solar cell comprises, from bottom to top, a conductive glass substrate, an electron transport layer, a functional layer, a passivation layer, a hole transport layer, and a metal electrode layer; the functional layer comprises monomer molecules, including phenolphthalein and phenolphthalein derivatives containing a Cardo ring, that is, the unit molecule is phenolphthalein or a phenolphthalein derivative containing a Cardo ring.

[0009] Optionally, the monomer molecule is represented by any of the following structural formulas:

[0010]

[0011] Optionally, the monomer molecule is obtained by reacting a precursor molecule with an inorganic salt at room temperature under stirring. The inorganic salt includes at least one selected from cesium carbonate (Cs₂CO₃), potassium carbonate (K₂CO₃), sodium carbonate (Na₂CO₃), potassium hydroxide (KOH), and sodium hydroxide (NaOH), and the precursor molecule is represented by any of the following structural formulas:

[0012]

[0013] If the inorganic salt is selected from cesium carbonate, potassium carbonate, and sodium carbonate, the precursor molecule reacts with the inorganic salt in an equimolar ratio. If the inorganic salt is selected from potassium hydroxide or sodium hydroxide, the molar ratio of the precursor molecule to the inorganic salt is 1:2 or 1:3 to ensure that the hydroxyl groups in the precursor molecule react with the inorganic salt in an equimolar ratio.

[0014] In an optional embodiment of the present invention, the functional layer is mainly composed of a perovskite light-absorbing layer I, which is formed by coating a precursor solution I containing monomer molecules. When the functional layer is mainly composed of the perovskite light-absorbing layer I, the photoelectric conversion efficiency of the perovskite solar cell can be increased to 23.1% to 24.2%. The perovskite light-absorbing layer I is formed by coating a precursor solution I containing monomer molecules. Specifically, when the functional layer is mainly composed of the perovskite light-absorbing layer I, the functional layer is formed by spin-coating the precursor solution I onto the electron transport layer, followed by pre-annealing, adding an organic cation solution, and then high-temperature annealing. The precursor solution I contains monomer molecules with a mass concentration of 0.5–3 mg / mL and lead iodide or lead bromide (PbBr2) with a molar concentration of 1.2–1.6 mol / L. The solvent of the precursor solution I is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is preferably 7–9:1–3.

[0015] In another optional embodiment of the present invention, the functional layer mainly consists of a monomer molecule passivation layer and a perovskite light absorption layer II arranged sequentially from bottom to top. The monomer molecule passivation layer and the perovskite light absorption layer II are respectively coated with a monomer molecule solution and a precursor solution II without monomer molecules. When the functional layer mainly consists of a monomer molecule passivation layer and a perovskite light absorption layer II arranged sequentially from bottom to top, the photoelectric conversion efficiency of the perovskite solar cell can be increased to 22.5% to 23.42%. The monomer passivation layer and perovskite light absorption layer II are respectively coated with a monomer solution and a precursor solution II containing no monomer molecules. Specifically, when the functional layer is mainly composed of a monomer passivation layer and a perovskite light absorption layer II arranged sequentially from bottom to top, the functional layer is formed by spin-coating a monomer solution and a precursor solution II sequentially onto an electron transport layer, followed by pre-annealing, adding an organic cation solution, and then high-temperature annealing. The monomer solution contains monomer molecules with a mass concentration of 0.5–3 mg / mL, and the solvent of the monomer solution is N,N-dimethylformamide. The precursor solution II contains lead iodide or lead bromide (PbBr2) with a molar concentration of 1.2–1.6 mol / L, and the solvent of the precursor solution II is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is preferably 7–9:1–3. The volume ratio of the monomer solution to the precursor solution II is 0.5–2:1.

[0016] Specifically, the organic cation solution comprises formamidin hydroiodide (FAI) at a mass concentration of 50–100 mg / mL, methylamine iodide (MAI) at a mass concentration of 5–10 mg / mL, and methylamine chloride (MACl) at a mass concentration of 5–10 mg / mL; the solvent of the organic cation solution is isopropanol (IPA).

[0017] Furthermore, the organic cation solution also contains at least one of methylammonium bromide (MABr), cesium iodide (CsI), and formamidinium chloride (FACl).

[0018] Specifically, the passivation layer is formed by spin-coating a passivation layer stock solution onto the functional layer. The passivation layer stock solution contains a passivation layer material with a concentration of 4-6 mg / mL. The passivation layer material includes phenylethyl iodide (PEAI) and / or phenylethyl iodide derivatives. The phenylethyl iodide derivatives include one or more of the phenylethyl iodide derivatives such as pF-PEAI, oF-PEAI, and mF-PEAI, in which the hydrogen atoms on the benzene ring are replaced by halogen elements.

[0019] Preferably, the material of the conductive glass substrate layer includes FTO (fluorine-doped tin oxide) or ITO (indium tin oxide);

[0020] Preferably, the material of the electron transport layer includes tin oxide;

[0021] Preferably, the material of the hole transport layer includes 4-tert-butylpyridine (tBP), lithium bis(trifluoromethane)sulfonylimide (Li-TFSI), and Spiro-OMeTAD;

[0022] Preferably, the material of the metal electrode layer includes molybdenum trioxide and silver.

[0023] II. A method for fabricating perovskite solar cells

[0024] The preparation method includes the following steps:

[0025] S1) Coating an electron transport layer on a conductive glass substrate: Prepare a SnO2 colloidal aqueous solution, sonicate it for 10-30 min and then filter it. Spin-coat the filtered SnO2 solution onto the FTO or ITO surface and anneal it to complete the preparation of the electron transport layer.

[0026] Preferably, step S1) specifically involves: mixing a 12% SnO2 solution by mass with deionized water at a volume ratio of 3:1 to obtain a SnO2 colloidal aqueous solution, ultrasonicating for 20 minutes, and then filtering. The filtered SnO2 solution is then spin-coated onto an FTO or ITO surface and annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the electron transport layer.

[0027] S2) Coating a functional layer onto the electron transport layer;

[0028] Optionally, step S2) specifically involves: preparing precursor solution I by adding an N,N-dimethylformamide solution of monomer molecules and lead iodide to dimethyl sulfoxide; spin-coating precursor solution I onto an electron transport layer; and then sequentially subjecting the solution to pre-annealing, dropwise addition of an organic cation solution, and annealing to form a functional layer on the electron transport layer; wherein precursor solution I contains monomer molecules with a mass concentration of 0.5–3 mg / mL and lead iodide or lead bromide with a molar concentration of 1.2–1.6 mol / L, and the solvent of precursor solution I is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide;

[0029] Optionally, step S2) specifically involves: sequentially spin-coating a monomer molecular solution and precursor solution II onto the electron transport layer, followed by sequential pre-annealing, dropwise addition of an organic cation solution, and annealing to form a functional layer on the electron transport layer; the monomer molecular solution contains monomer molecules with a mass concentration of 0.5–3 mg / mL, and the solvent of the monomer molecular solution is N,N-dimethylformamide; the precursor solution II contains lead iodide or lead bromide with a molar concentration of 1.2–1.6 mol / L, and the solvent of the precursor solution II is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide.

[0030] In step S2), the organic cation solution comprises formamidinium hydroiodate (FAI) at a concentration of 50–100 mg / mL, methylamine iodide (MAI) at a concentration of 5–10 mg / mL, and methylamine chloride (MACl) at a concentration of 5–10 mg / mL; the solvent of the organic cation solution is isopropanol (IPA). The organic cation solution further comprises at least one of methylamine bromide (MABr), cesium iodide (CsI), and formamidinium chloride (FACl).

[0031] In step S2), the spin coating conditions are: spin coater speed of 1000-2000 r / min, time of 20-40 s; the pre-annealing conditions are: pre-annealing temperature of 60-80℃, pre-annealing time of 30-90 s; and the annealing conditions are: annealing temperature of 100-150℃, annealing time of 10-20 min.

[0032] S3) Coating a passivation layer onto the functional layer; Specifically, step S3) involves coating the functional layer with a passivation solution to form a passivation layer.

[0033] The passivation layer stock solution contains a passivation layer material at a concentration of 4-6 mg / mL. The passivation layer material includes phenylethyl iodide (PEAI) and / or phenylethyl iodide derivatives. The phenylethyl iodide derivatives include one or more of the following phenylethyl iodide derivatives in which the hydrogen atoms on the benzene ring are replaced by halogen elements: pF-PEAI, oF-PEAI, and mF-PEAI.

[0034] S4) Coat the hole transport layer on the passivation layer.

[0035] S5) Deposit a metal electrode onto the hole transport layer to obtain the perovskite solar cell.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. This invention focuses on the passivation of defects in the perovskite light absorption layer. Based on the two-step preparation method of perovskite solar cells, only monomer molecules are added to the precursor solution or the monomer molecule solution is spin-coated separately before spin-coating the precursor solution. The photoelectric conversion efficiency of the resulting device is increased by 9.7% compared with the standard device, which significantly improves the device efficiency.

[0038] 2. This invention utilizes the interaction between monomer molecules and lead and iodine ions in the perovskite solution to regulate the growth rate and orientation of perovskite crystals, optimizing crystal morphology and lattice structure. The ester functional groups of the monomer molecules can improve device performance by enhancing interfacial stability, reducing defects, promoting better film formation, and passivating surface defects. Cesium ions can enhance the stability of the perovskite layer and improve its electronic properties. Furthermore, the monomer molecules can help reduce ion migration, improve crystal quality, and increase the efficiency of solar cells. Attached Figure Description

[0039] Figure 1 These are structural diagrams of various precursor molecules in this invention; wherein, (a) is precursor molecule 1, (b) is precursor molecule 2, and (c) is precursor molecule 3;

[0040] Figure 2 These are structural diagrams of various monomer molecules in this invention; wherein, (a) is monomer molecule 1, (b) is monomer molecule 2, and (c) is monomer molecule 3;

[0041] Figure 3 These are the JV curves of the perovskite solar cells obtained in Example 1 and Comparative Example 1 of this invention;

[0042] Figure 4 This is a statistical chart of photovoltaic parameters of the perovskite solar cells obtained in Example 1 and Comparative Example 1 of the present invention;

[0043] Figure 5 These are the JV curves of the perovskite solar cells obtained in Example 2 and Comparative Example 2 of this invention;

[0044] Figure 6 This is a statistical chart of photovoltaic parameters of the perovskite solar cells obtained in Example 2 and Comparative Example 2 of the present invention;

[0045] Figure 7 These are the JV curves of the perovskite solar cells obtained in Example 3 and Comparative Example 3 of this invention;

[0046] Figure 8 This is a statistical chart of photovoltaic parameters of the perovskite solar cells obtained in Example 3 and Comparative Example 3 of the present invention;

[0047] Figure 9 These are the JV curves of the perovskite solar cells obtained in Example 4 and Comparative Example 4 of this invention;

[0048] Figure 10 These are statistical graphs of photovoltaic parameters of the perovskite solar cells obtained in Example 4 and Comparative Example 4 of this invention;

[0049] Figure 11 These are the JV curves of the perovskite solar cells obtained in Example 5 and Comparative Example 5 of this invention;

[0050] Figure 12 This is a statistical chart of photovoltaic parameters of the perovskite solar cells obtained in Example 5 and Comparative Example 5 of the present invention;

[0051] Figure 13 These are the JV curves of the perovskite solar cells obtained in Example 6 and Comparative Example 6 of this invention;

[0052] Figure 14 This is a statistical chart of photovoltaic parameters of the perovskite solar cells obtained in Example 6 and Comparative Example 6 of the present invention. Detailed Implementation

[0053] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “described,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0054] The principle of this invention is as follows: In the fabrication of perovskite solar cells, different concentrations of monomer molecules are added to the perovskite precursor solution, or different concentrations of monomer molecule solutions are spin-coated before spin-coating the perovskite precursor solution. The ester functional groups contained in the monomer molecules can affect the Pb content in the perovskite. 2+ The monomer can coordinate to form adducts and also form coordinate bonds with SnO2, reducing oxygen vacancies on the SnO2 surface and acting as a Lewis base. Furthermore, the monomer can also react with undercoordinated Pb at the perovskite buried interface. 2+ The formation of coordination bonds and their synergistic effects influence the formation and concentration of vacancy defects in perovskites, thus regulating vacancy defects in perovskite crystals and affecting charge transport and carrier lifetime, significantly increasing the turn-on voltage V. oc The fill factor FF ultimately improves the photoelectric conversion efficiency of perovskite solar cells.

[0055] The above monomer molecules are derived from Figure 1 (a)~ Figure 1The product of the reaction of any precursor molecule in (c) with any inorganic salt such as cesium carbonate (Cs₂CO₃), potassium carbonate (K₂CO₃), sodium carbonate (Na₂CO₃), potassium hydroxide (KOH), or sodium hydroxide (NaOH) has the structural formula as follows: Figure 2 (a)~ Figure 2 As shown in (c).

[0056] Specific embodiments of the present invention are as follows:

[0057] In the embodiments of this invention, the structural formula selected is as follows: Figure 2 Monomer molecule 1 is shown in (a). Figure 2 Monomer molecule 2 shown in (b), and Figure 2 Monomer molecule 3 is shown in (c).

[0058] Monomer molecule 1 can be obtained through structural formulas such as Figure 1 The precursor molecule 1 shown in (a) is obtained by reacting with cesium carbonate. The structural formula of precursor molecule 1 is:

[0059]

[0060] Monomer molecule 2 can be obtained through structural formulas such as Figure 1 The precursor molecule 2 shown in (b) is obtained by reacting potassium carbonate. The structural formula of precursor molecule 2 is:

[0061]

[0062] Monomer molecule 3 can be obtained through structural formulas such as Figure 1 The precursor molecule 3 shown in (c) is obtained by reacting it with sodium carbonate. The structural formula of precursor molecule 3 is:

[0063]

[0064] Example 1

[0065] This embodiment uses a perovskite precursor solution I containing 0.9 mg / mL monomer molecules 1 to prepare a perovskite solar cell. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of perovskite light-absorbing layer I. The specific steps are as follows:

[0066] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol, and ethanol solutions, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0067] Step 2: Weigh 318.32 mg of cesium carbonate and 325.82 mg of precursor molecule 1 and dissolve them in 2147 mL of DMF. Stir at 150 °C for 4 h to obtain monomer molecule 1 solution, and dilute its concentration to 1 mg / mL. Weigh 691.5 mg of PbI2 and dissolve it in 900 μL of DMF (containing monomer molecule 1 at a concentration of 1 mg / mL) and 100 μL of DMSO. Stir and dissolve for 12 h, then filter to obtain precursor solution I. Spin-coat 50 μL of precursor solution I onto the surface of the electron transport layer at a spin coater speed of 1500 r / min for 30 s, and then pre-anneal at 75 °C for 1 min. After the substrate was brought back to room temperature, an organic cation solution was dropped into the center of the perovskite substrate. The organic cation was prepared by dissolving 90 mg of FAI, 6.4 mg of MAI and 9 mg of MACl in 1 mL of isopropanol (IPA). The substrate was then placed on a hot plate at 150 °C and annealed for 15 min to form the perovskite light-absorbing layer I.

[0068] Step 3: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 4.8 mg / mL onto the substrate surface.

[0069] Step 4: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0070] Step 5: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0071] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 24.20%.

[0072] Example 2

[0073] This embodiment uses a perovskite precursor solution I containing 1.35 mg / mL monomer molecules 1 to prepare a perovskite solar cell. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of perovskite light-absorbing layer I. The specific steps are as follows:

[0074] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol (IPA), and ethanol solution, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0075] Step 2: Weigh 318.32 mg of cesium carbonate and 325.82 mg of precursor molecule 1 and dissolve them in 2147 mL of DMF. Stir at 150 °C for 4 h to obtain monomer molecule 1 solution, and dilute its concentration to 1.5 mg / mL. Weigh 691.5 mg of PbI2 and dissolve it in 900 μL of DMF (containing monomer molecule 1 at a concentration of 1.5 mg / mL) and 100 μL of DMSO. Stir and dissolve for 12 h, then filter to obtain precursor solution I. Spin-coat 60 μL of precursor solution I onto the surface of the electron transport layer at a spin coater speed of 1500 r / min for 30 s, and then pre-anneal at 75 °C for 1 min. After the substrate was brought back to room temperature, an organic cation solution was dropped into the center of the perovskite substrate. The organic cation was prepared by dissolving 90 mg of FAI, 6.4 mg of MAI and 9 mg of MACl in 1 mL of IPA. The substrate was then annealed on a hot plate at 150 °C for 15 min to form the perovskite light-absorbing layer I.

[0076] Step 3: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 4.8 mg / mL onto the substrate surface.

[0077] Step 4: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0078] Step 5: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0079] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 22.70%.

[0080] Example 3

[0081] This embodiment uses a solution containing monomer molecules 1 (1 mg / mL) and a precursor solution II containing lead iodide but no monomer molecules to prepare a perovskite solar cell with a passivation layer containing 1 mg / mL monomer molecules. The functional layer of the perovskite solar cell obtained in this embodiment mainly consists of a monomer molecule passivation layer and a perovskite light-absorbing layer II arranged sequentially from bottom to top. The specific steps are as follows:

[0082] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol, and ethanol solutions, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0083] Step 2: Weigh 318.32 mg of cesium carbonate and 325.82 mg of precursor molecule 1 and dissolve them in 2147 mL of DMF. Stir at 150 °C for 4 h to obtain a monomer molecule 1 solution, and dilute its concentration to 1 mg / mL. Take 50 μL of monomer molecule 1 solution and spin-coat it onto the surface of the electron transport layer to form a monomer molecule 1 passivation layer.

[0084] Step 3: Weigh 691.5 mg of PbI₂ and dissolve it in 900 μL of DMF and 100 μL of DMSO. After stirring and dissolving for 12 h, filter to obtain precursor solution II. Spin-coat 70 μL of precursor solution II onto the surface of the monomer molecule 1 passivation layer using a spin coater at 1500 r / min for 30 s. Then, pre-anneal the substrate at 75 °C for 1 min. After the substrate has returned to room temperature, add an organic cation solution dropwise to the center of the perovskite substrate. The organic cation solution is prepared by dissolving 60 mg of FAI, 5.3 mg of MAI, and 6 mg of MACl in 1 mL of IPA. Anneal the substrate at 150 °C for 15 min to form the perovskite light-absorbing layer II.

[0085] Step 4: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 4.5 mg / mL onto the substrate surface.

[0086] Step 5: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0087] Step 6: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0088] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 23.71%.

[0089] Example 4

[0090] This embodiment uses a solution containing monomer molecule 1 with a mass concentration of 2.1 mg / mL and a precursor solution II containing lead iodide but no monomer molecules to prepare a perovskite solar cell with a passivation layer containing 2.1 mg / mL monomer molecule 1. The functional layer of the perovskite solar cell obtained in this embodiment mainly consists of a monomer molecule passivation layer and a perovskite light-absorbing layer II arranged sequentially from bottom to top. The specific steps are as follows:

[0091] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol, and ethanol solutions, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0092] Step 2: Weigh 318.32 mg of cesium carbonate and 325.82 mg of precursor molecule 1 and dissolve them in 2147 mL of DMF. Stir at 150 °C for 4 h, filter to obtain a monomer molecule solution, and dilute its concentration to 2.1 mg / mL. Take 90 μL of monomer molecule 1 solution and spin-coat it onto the surface of the electron transport layer to form a monomer molecule 1 passivation layer.

[0093] Step 3: Weigh 691.5 mg of PbI₂ and dissolve it in 900 μL LDMSO and 100 μL LDMSO. After stirring and dissolving for 10 h, filter to obtain precursor solution II. Spin-coat 80 μL of precursor solution II onto the surface of the monomer molecule 1 passivation layer using a spin coater at 1500 r / min for 30 s. Then, pre-anneal the substrate at 75 °C for 1 min. After the substrate has returned to room temperature, add an organic cation solution dropwise to the center of the perovskite substrate. The organic cation is prepared by dissolving 90 mg of FAI, 6.4 mg of MAI, and 9 mg of MACl in 1 mL of IPA. Anneal the substrate at 150 °C for 10 min to form the perovskite light-absorbing layer II.

[0094] Step 4: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 4 mg / mL onto the substrate surface.

[0095] Step 5: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0096] Step 6: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0097] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 22.19%.

[0098] Example 5

[0099] This embodiment uses a perovskite precursor solution I containing 1 mg / mL monomer molecules 2 to prepare a perovskite solar cell. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of perovskite light-absorbing layer I. The specific steps are as follows:

[0100] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol, and ethanol solutions, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0101] Step 2: Weigh 317 mg of potassium carbonate and 138 mg of precursor molecule 2 and dissolve them in 2220 mL of DMF. Stir at 150 °C for 4 h to obtain monomer molecule 2 solution, and dilute its concentration to 1 mg / mL. Weigh 691.5 mg of PbI2 and dissolve it in 900 μL of DMF (containing monomer molecule 2 at a concentration of 1 mg / mL) and 100 μL of DMSO. Stir and dissolve for 12 h, then filter to obtain precursor solution I. Spin-coat 90 μL of precursor solution I onto the surface of the electron transport layer at a spin coater speed of 1500 r / min for 30 s, and then pre-anneal at 75 °C for 1 min. After the substrate was brought back to room temperature, an organic cation solution was dropped into the center of the perovskite substrate. The organic cation was prepared by dissolving 90 mg of FAI, 6.4 mg of MAI and 9 mg of MACl in 1 mL of isopropanol IPA. The substrate was then placed on a hot plate at 150 °C and annealed for 15 min to form the perovskite light absorption layer I.

[0102] Step 3: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 3.5 mg / mL onto the substrate surface.

[0103] Step 4: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0104] Step 5: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0105] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 21.32%.

[0106] Example 6

[0107] This embodiment uses a solution containing monomer molecule 3 with a mass concentration of 0.5 mg / mL and a precursor solution II containing lead iodide but no monomer molecules to prepare a perovskite solar cell with a 0.5 mg / mL monomer molecule 3 passivation layer. The functional layer of the perovskite solar cell obtained in this embodiment mainly consists of a monomer molecule passivation layer and a perovskite light-absorbing layer II arranged sequentially from bottom to top. The specific steps are as follows:

[0108] Step 1: After sequentially cleaning the ITO conductive glass with deionized water, isopropanol, and ethanol solutions, dry it with nitrogen gas and then treat it with an ultraviolet ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water at a volume ratio of 3:1 and sonicate for 20 minutes. Spin-coat the prepared SnO2 onto the ITO surface and anneal it on a hot plate at 150°C for 30 minutes to form an electron transport layer.

[0109] Step 2: Weigh 320 mg of sodium carbonate and 106 mg of precursor molecule 3 and dissolve them in 1704 mL of DMF. Stir at 150 °C for 4 h to obtain a monomer molecule 3 solution, and dilute its concentration to 1 mg / mL. Spin-coat 50 μL of monomer molecule 3 solution onto the surface of the electron transport layer to form a monomer molecule 3 passivation layer.

[0110] Step 3: Weigh 691.5 mg of PbI2 and dissolve it in 900 μL of DMF and 100 μL of DMSO. After stirring and dissolving for 12 h, filter to obtain precursor solution II. Spin-coat 100 μL of precursor solution II onto the surface of monomer molecule 3 passivation layer using a spin coater at 1500 r / min for 30 s, and then pre-anneal at 75 °C for 1 min. After the substrate is brought back to room temperature, add an organic cation solution dropwise to the center of the perovskite substrate. The organic cation solution is prepared by dissolving 60 mg of FAI, 5.3 mg of MAI, and 6 mg of MACl in 1 mL of IPA. Anneal the substrate at 150 °C for 15 min to form perovskite light-absorbing layer II.

[0111] Step 4: Spin-coat a passivation layer of phenylethyl iodide (PEAI) with a concentration of 4.5 mg / mL onto the substrate surface.

[0112] Step 5: An acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI, and a chlorobenzene solution containing Spiro-OMeTAD are spin-coated onto a perovskite substrate as a hole transport layer.

[0113] Step 6: Place the substrate in the vapor deposition apparatus, first vapor deposit 4.5 nm of molybdenum trioxide, then vapor deposit 80 nm of silver as the back electrode.

[0114] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 21.19%.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 1 is that in step 2, no monomer molecules were added to the perovskite precursor solution I.

[0117] The photoelectric conversion efficiency of the perovskite solar cell obtained in this comparative example is 21.90%.

[0118] Comparative Example 2

[0119] The difference between this comparative example and Example 2 is that in step 2, monomer molecule 1 was not added to the perovskite precursor solution I.

[0120] Comparative Example 3

[0121] The difference between this comparative example and Example 3 is that this comparative example omits step 2 and directly proceeds to step 3.

[0122] Comparative Example 4

[0123] The difference between this comparative example and Example 4 is that this comparative example omits step 2 and directly proceeds to step 3.

[0124] Comparative Example 5

[0125] The difference between this comparative example and Example 5 is that in step 2, no monomer molecules were added to the perovskite precursor solution I.

[0126] Comparative Example 6

[0127] The difference between this comparative example and Example 6 is that this comparative example omits step 2 and directly proceeds to step 3.

[0128] The JV curve tests and photovoltaic parameter statistics of the perovskite solar cells obtained using Examples 1 to 6 and Comparative Examples 1 to 6 of the present invention are as follows:

[0129] 1. JV curve test

[0130] The aforementioned battery uses silver as the back electrode. During JV testing, the instrument calibration and assembly method for the final perovskite solar cell device are as follows: First, the Keithley instrument is calibrated using a standard silicon-based solar cell. Then, the prepared battery is placed within it, with the back electrode in contact with the probe in the test cell mold. The positive and negative electrodes of the test cell mold are connected to the positive and negative electrodes of the calibrated Keithley instrument, respectively. A voltage of 1.2V is applied, and the battery is subjected to JV curve testing.

[0131] Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 and Figure 13 The JV curves are as follows: JV curves of perovskite solar cells containing 0.9 mg / mL monomer molecules 1 in perovskite precursor solution I (Example 1) and the control sample (Comparative Example 1); JV curves of perovskite solar cells containing 1.35 mg / mL monomer molecules 1 in perovskite precursor solution I (Example 2) and the control sample (Comparative Example 2); JV curves of perovskite solar cells containing a passivation layer of 1 mg / mL monomer molecules 1 (Example 3) and the control sample (Comparative Example 3); JV curves of perovskite solar cells containing a passivation layer of 2.1 mg / mL monomer molecules 1 (Example 4) and the control sample (Comparative Example 4); JV curves of perovskite solar cells containing 1 mg / mL monomer molecules 2 in perovskite precursor solution I (Example 5) and the control sample (Comparative Example 2); and JV curves of perovskite solar cells containing a passivation layer of 0.5 mg / mL monomer molecules 1 (Example 6) and the control sample (Comparative Example 6).

[0132] from Figure 3 As can be seen, the perovskite solar cell prepared by adding monomer molecule 1 to the perovskite precursor solution has a maximum photoelectric conversion efficiency of 24.2% (Example 1), with corresponding current density Jsc, onset voltage Voc, and fill factor FF of 25.49 mA / cm². 2 The photoelectric conversion efficiency of Example 1 was 11.82% higher than that of Comparative Example 1, at 1.147V and 82.79%.

[0133] from Figure 5 As can be seen, the perovskite solar cell containing a 1 mg / mL monomer molecule passivation layer (Example 3) has a maximum photoelectric conversion efficiency of 23.71%, with corresponding current density Jsc, onset voltage Voc, and fill factor FF of 25.40 mA / cm². 2 The photoelectric conversion efficiency of Example 3 was 1.134V and 82.30%. Compared to Comparative Example 3, Example 3 showed an 8.26% improvement in photoelectric conversion efficiency.

[0134] 2. Statistical distribution chart of photovoltaic parameters.

[0135] Figure 4 , Figure 6 , Figure 8 , Figure 10 , Figure 12 and Figure 14The photovoltaic parameter statistics are as follows: perovskite solar cell with perovskite precursor solution containing 0.9 mg / mL monomer molecule 1 (Example 1) and control sample (Comparative Example 1); perovskite solar cell with perovskite precursor solution containing 1.35 mg / mL monomer molecule 1 (Example 2) and control sample (Comparative Example 2); perovskite solar cell with passivation layer containing 1 mg / mL monomer molecule 1 (Example 3) and control sample (Comparative Example 3); perovskite solar cell with passivation layer containing 2.1 mg / mL monomer molecule 1 (Example 4) and control sample (Comparative Example 4); perovskite solar cell with perovskite precursor solution I containing 1 mg / mL monomer molecule 2 (Example 5) and control sample (Comparative Example 2); and perovskite solar cell with passivation layer containing 0.5 mg / mL monomer molecule 1 (Example 6) and control sample (Comparative Example 6).

[0136] from Figure 4 As can be seen from this, the opening pressure V in Example 1 oc The fill factor FF was significantly improved, which may be because the ester functional group contained in monomer molecule 1 affects the Pb in perovskite. 2+ Coordination can form adducts, and it can also form coordination bonds with SnO2, reducing oxygen vacancies on the SnO2 surface and acting as a Lewis base. It can also react with undercoordinated Pb at the perovskite buried interface. 2+ Coordination bonds are formed for synergistic effects.

[0137] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. It should be noted that, for those skilled in the art, the present invention is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary technical means in the art that are not disclosed in this application.

Claims

1. A perovskite solar cell, characterized in that: The perovskite solar cell comprises, from bottom to top, a conductive glass substrate, an electron transport layer, a functional layer, a passivation layer, a hole transport layer, and a metal electrode layer; the functional layer contains monomer molecules, including phenolphthalein and phenolphthalein derivatives containing a Cardo ring. The functional layer is mainly composed of a perovskite light absorption layer I, which is coated with a precursor solution I containing monomer molecules; or, the functional layer is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged sequentially from bottom to top, wherein the monomer molecule passivation layer and the perovskite light absorption layer II are coated with a monomer molecule solution and a precursor solution II without monomer molecules, respectively. The monomer molecule can be represented by any of the following structural formulas: And / or, the monomer molecule is obtained by reacting a precursor molecule with an inorganic salt at room temperature, wherein the inorganic salt includes at least one of cesium carbonate, potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, and the precursor molecule is represented by any of the following structural formulas:

2. The perovskite solar cell according to claim 1, characterized in that: When the functional layer is mainly composed of perovskite light absorption layer I, the functional layer is formed by spin-coating precursor solution I onto the electron transport layer, followed by pre-annealing, dropwise addition of organic cation solution, and then high-temperature annealing; the precursor solution I contains monomer molecules with a mass concentration of 0.5-3 mg / mL and lead iodide or lead bromide with a molar concentration of 1.2-1.6 mol / L. When the functional layer is mainly composed of a monomer passivation layer and a perovskite light absorption layer II arranged sequentially from bottom to top, the functional layer is formed by spin-coating a monomer solution and a precursor solution II onto an electron transport layer, followed by pre-annealing, adding an organic cation solution, and then high-temperature annealing; the monomer solution contains monomer molecules with a mass concentration of 0.5–3 mg / mL; the precursor solution II contains lead iodide or lead bromide with a molar concentration of 1.2–1.6 mol / L.

3. The perovskite solar cell according to claim 2, characterized in that: The organic cation solution contains formamidin hydroiodate at a mass concentration of 50–100 mg / mL, methyl iodide at a mass concentration of 5–10 mg / mL, and methyl ammonium chloride at a mass concentration of 5–10 mg / mL.

4. The perovskite solar cell according to claim 1, characterized in that: The passivation layer is formed by spin-coating a passivation layer stock solution onto the functional layer. The passivation layer stock solution contains a passivation layer material with a concentration of 4-6 mg / mL. The passivation layer material includes phenylethyl iodide and / or phenylethyl iodide derivatives. The phenylethyl iodide derivatives include one or more of pF-PEAI, oF-PEAI, and mF-PEAI.

5. The perovskite solar cell according to claim 1, characterized in that: The conductive glass substrate layer is made of FTO or ITO; and / or the electron transport layer is made of tin oxide; and / or the hole transport layer is made of 4-tert-butylpyridine, lithium bis(trifluoromethanesulfonylimide) salt and Spiro-OMeTAD; and / or the metal electrode layer is made of molybdenum trioxide and silver.

6. A method for preparing a perovskite solar cell as described in any one of claims 1 to 5, characterized in that: The preparation method includes the following steps: S1) Coating an electron transport layer onto a conductive glass substrate; S2) Coating a functional layer onto the electron transport layer; S3) A passivation layer is coated on the functional layer; S4) Coat the hole transport layer on the passivation layer; S5) Deposit a metal electrode onto the hole transport layer to obtain the perovskite solar cell.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that: Step S2) specifically involves spin-coating precursor solution I onto the electron transport layer, followed by pre-annealing, dropwise addition of organic cation solution, and annealing to form a functional layer on the electron transport layer; the precursor solution I contains monomer molecules with a mass concentration of 0.5–3 mg / mL and lead iodide or lead bromide with a molar concentration of 1.2–1.6 mol / L. Alternatively, step S2) specifically involves: sequentially spin-coating a monomer molecule solution and precursor solution II onto the electron transport layer, followed by sequential pre-annealing, dropwise addition of an organic cation solution, and annealing to form a functional layer on the electron transport layer; the monomer molecule solution contains monomer molecules with a mass concentration of 0.5–3 mg / mL; the precursor solution II contains lead iodide or lead bromide with a molar concentration of 1.2–1.6 mol / L.

8. The method for preparing a perovskite solar cell according to claim 7, characterized in that: In step S2), the spin coating conditions are: spin coater speed of 1000-2000 r / min, time of 20-40 s; the pre-annealing conditions are: pre-annealing temperature of 60-80℃, pre-annealing time of 30-90 s; and the annealing conditions are: annealing temperature of 100-150℃, annealing time of 10-20 min.

9. The method for preparing a perovskite solar cell according to claim 6, characterized in that: Step S3) specifically involves coating a passivation layer stock solution onto the functional layer to form a passivation layer; the passivation layer stock solution contains a passivation layer material with a concentration of 4-6 mg / mL, the passivation layer material includes phenylethyl iodide and / or phenylethyl iodide derivatives, and the phenylethyl iodide derivatives include one or more of pF-PEAI, oF-PEAI and mF-PEAI.

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