Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a conductive glass substrate layer, an electron transport layer, a functional layer, a passivation layer, a hole transport layer and a metal electrode layer which are sequentially arranged from bottom to top, the functional layer is mainly composed of a perovskite light absorption layer I, or a monomer molecule passivation layer and a perovskite light absorption layer II which are sequentially arranged from bottom to top; the perovskite light absorption layer I is formed by coating the electron transport layer with a precursor solution I containing monomer molecules, and the monomer molecule passivation layer and the perovskite light absorption layer II are formed by sequentially coating the electron transport layer with a monomer molecule solution and a precursor solution II without monomer molecules. According to the perovskite solar cell, charge transfer and carrier lifetime are influenced by monomer molecules, so that the open voltage and the filling factor are greatly improved, and finally the photoelectric conversion efficiency of the perovskite solar cell is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and in particular relates to a perovskite solar cell and a preparation method thereof. Background Art

[0002] In an era of rapid economic globalization and a sharp increase in population, energy shortages are becoming increasingly serious. Today, the world's main energy supply is the combustion of fossil fuels such as oil, natural gas and coal, but this is not a renewable energy source and cannot meet future human needs. In addition, the combustion of fossil fuels will emit a large amount of carbon dioxide.

[0003] Therefore, not only for energy shortage, new energy development is needed to provide important guarantees for the sustainable development of human civilization. Perovskite solar cells are the most promising new generation of clean energy, and they are developing rapidly. The current highest photoelectric conversion efficiency is 26.41%. However, there is still a certain gap between the actual photoelectric conversion efficiency of perovskites and the theoretical photoelectric conversion efficiency. The main reasons include: defects in the perovskite light absorption layer itself, interface defects between the perovskite light absorption layer and the transmission layer, which lead to non-radiative recombination and large opening voltage loss, resulting in the inability to improve efficiency, which is fatal to the photoelectric performance.

[0004] For the preparation of perovskite solar cells, the two-step method can pre-adjust the lead iodide template, which has good operability and commercial potential. However, the growth of perovskite crystals on the lead iodide substrate and the penetration of organic cation solutions mean that the perovskite grains are prone to become disordered and non-radiative recombination sites are easily introduced, affecting the photovoltaic efficiency and stability of the device. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a perovskite solar cell and a preparation method thereof. The present invention improves the photoelectric conversion efficiency of the perovskite solar cell by introducing monomer molecules.

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

[0007] 1. A perovskite solar cell

[0008] The perovskite solar cell includes a conductive glass substrate layer, an electron transport layer, a functional layer, a passivation layer, a hole transport layer and a metal electrode layer arranged in sequence from bottom to top; the components of the functional layer include monomer molecules, and the monomer molecules include 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 stirring a precursor molecule and an inorganic salt at room temperature. The inorganic salt includes at least one of cesium carbonate (Cs2CO3), potassium carbonate (K2CO3), sodium carbonate (Na2CO3), potassium hydroxide (KOH) and sodium hydroxide (NaOH), and the precursor molecule is represented by any one 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 equal molar 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 equal molar ratio.

[0014] As an optional embodiment of the present invention, the functional layer is mainly composed of a perovskite light absorbing layer I, and the perovskite light absorbing layer I is coated by 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 absorption layer I is coated with a precursor solution I containing monomer molecules. Specifically, when the functional layer is mainly composed of the perovskite light absorption layer I, the functional layer is formed by spin-coating the precursor solution I on the electron transport layer, pre-annealing, dripping an organic cationic solution, and then annealing at a high temperature; the precursor solution I contains monomer molecules with a mass concentration of 0.5 to 3 mg / mL and lead iodide or lead bromide (PbBr2) with a molar concentration of 1.2 to 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 and dimethyl sulfoxide is preferably 7 to 9:1 to 3.

[0015] As another optional embodiment of the present invention, the functional layer is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged in sequence from bottom to top, and the monomer molecule passivation layer and the perovskite light absorption layer II are coated by a monomer molecule solution and a precursor solution II without monomer molecules, respectively. When the functional layer is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged in sequence from bottom to top, the photoelectric conversion efficiency of the perovskite solar cell can be increased to 22.5% to 23.42%. 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. Specifically, when 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, the functional layer is formed by spin-coating a monomer molecule solution and a precursor solution II on an electron transport layer in sequence, pre-annealing, dripping an organic cation solution, and then annealing at a high temperature; the monomer molecule solution contains monomer molecules with a mass concentration of 0.5 to 3 mg / mL, and the solvent of the monomer molecule solution is N,N-dimethylformamide; the precursor solution II contains lead iodide or lead bromide (PbBr2) with a molar concentration of 1.2 to 1.6 mol / L, and the solvent of the precursor solution II 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 to 9:1 to 3. The volume ratio of the monomer molecule solution to the precursor solution II is 0.5 to 2:1.

[0016] Specifically, the organic cationic solution contains formamidine hydroiodide (FAI) with a mass concentration of 50 to 100 mg / mL, methylammonium iodide (MAI) with a mass concentration of 5 to 10 mg / mL, and methylammonium chloride (MACl) with a mass concentration of 5 to 10 mg / mL; the solvent of the organic cationic solution is isopropyl alcohol (IPA).

[0017] Furthermore, the organic cationic solution further comprises at least one of methyl ammonium bromide (MABr), cesium iodide (CsI) and formamidine chloride (FACl).

[0018] Specifically, the passivation layer is formed by spin coating a passivation layer stock solution on the functional layer, wherein the passivation layer stock solution contains a passivation layer material with a concentration of 4 to 6 mg / mL, and the passivation layer material includes phenethylamine iodide (PEAI) and / or phenethylamine iodide derivatives, and the phenethylamine iodide derivatives include one or more phenethylamine 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)sulfonyl imide (Li-TFSI) and Spiro-OMeTAD;

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

[0023] 2. A method for preparing a perovskite solar cell

[0024] The preparation method comprises the following steps:

[0025] S1) coating an electron transport layer on the conductive glass substrate layer: preparing a SnO2 colloidal aqueous solution, subjecting it to ultrasonic treatment for 10 to 30 minutes and filtering it, spin-coating the filtered SnO2 solution on the FTO or ITO surface, and completing the preparation of the electron transport layer after annealing;

[0026] Preferably, the step S1) is specifically as follows: a 12% SnO2 solution is mixed with deionized water in a volume ratio of 3:1 to obtain a SnO2 colloidal aqueous solution, and the mixture is ultrasonically treated for 20 minutes and then filtered. The filtered SnO2 solution is spin-coated on the 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 on the electron transport layer;

[0028] Optionally, the step S2) is specifically as follows: adding an N,N-dimethylformamide solution of monomer molecules and lead iodide to dimethyl sulfoxide to prepare a precursor solution I, spin coating the precursor solution I on the electron transport layer, and then sequentially performing pre-annealing, dripping an 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 to 3 mg / mL and lead iodide or lead bromide with a molar concentration of 1.2 to 1.6 mol / L, and the solvent of the precursor solution I is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide;

[0029] Optionally, the step S2) is specifically as follows: spin coating a monomer molecule solution and a precursor solution II on the electron transport layer in sequence, and then pre-annealing, adding an organic cationic solution and annealing in sequence to form a functional layer on the electron transport layer; the monomer molecule solution contains monomer molecules with a mass concentration of 0.5 to 3 mg / mL, and the solvent of the monomer molecule solution is N,N-dimethylformamide; the precursor solution II contains lead iodide or lead bromide with a molar concentration of 1.2 to 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 the step S2), the organic cationic solution comprises formamidine hydroiodide (FAI) at a concentration of 50-100 mg / mL, methylammonium iodide (MAI) at a concentration of 5-10 mg / mL, and methylammonium chloride (MACl) at a concentration of 5-10 mg / mL; the solvent of the organic cationic solution is isopropyl alcohol (IPA). The organic cationic solution also comprises at least one of methylammonium bromide (MABr), cesium iodide (CsI), and formamidine chloride (FACl).

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

[0032] S3) coating a passivation layer on the functional layer; the step S3) specifically comprises: coating a passivation layer stock solution on the functional layer to form a passivation layer.

[0033] The passivation layer stock solution contains a passivation layer material with a concentration of 4 to 6 mg / mL, and the passivation layer material includes phenethylamine iodide (PEAI) and / or phenethylamine iodide derivatives, and the phenethylamine iodide derivatives include one or more phenethylamine 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.

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

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

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

[0037] 1. The present invention is aimed at the research 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 separately spin-coated before the precursor solution is spin-coated. The photoelectric conversion efficiency of the obtained device is increased by 9.7% compared with the standard device, which greatly improves the device efficiency.

[0038] 2. The present invention adjusts the growth rate and direction of perovskite crystals and optimizes the morphology and lattice structure of crystals through the interaction between monomer molecules and lead ions and iodine ions in perovskite solution. The ester functional groups of monomer molecules can improve device performance by enhancing interface 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. In addition, monomer molecules can also help reduce ion migration, improve crystal quality, and improve the efficiency of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a structural diagram of various precursor molecules in the present invention; wherein (a) is precursor molecule 1, (b) is precursor molecule 2, and (c) is precursor molecule 3;

[0040] Figure 2 1 is a structural diagram of various monomer molecules in the present invention; wherein (a) is monomer molecule 1, (b) is monomer molecule 2, and (c) is monomer molecule 3;

[0041] Figure 3 1 is the JV curve of the perovskite solar cell obtained in Example 1 of the present invention and Comparative Example 1;

[0042] Figure 4 Statistical graphs of photovoltaic parameters of perovskite solar cells obtained in Example 1 of the present invention and Comparative Example 1;

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

[0044] Figure 6 Statistical graphs of photovoltaic parameters of perovskite solar cells obtained in Example 2 of the present invention and Comparative Example 2;

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

[0046] Figure 8 Statistical graphs of photovoltaic parameters of perovskite solar cells obtained in Example 3 of the present invention and Comparative Example 3;

[0047] Fig. 9 1 is the JV curve of the perovskite solar cell obtained in Example 4 of the present invention and Comparative Example 4;

[0048] Fig.10 Statistical graphs of photovoltaic parameters of perovskite solar cells obtained in Example 4 of the present invention and Comparative Example 4;

[0049] Fig.11 5 are JV curves of the perovskite solar cells obtained in Example 5 of the present invention and Comparative Example 5;

[0050] Fig.12 Statistical graphs of photovoltaic parameters of perovskite solar cells obtained in Example 5 of the present invention and Comparative Example 5;

[0051] Fig.13 5 are JV curves of the perovskite solar cells obtained in Example 6 of the present invention and Comparative Example 6;

[0052] Fig.14 It is a statistical graph of photovoltaic parameters of the perovskite solar cells obtained in Example 6 of the present invention and Comparative Example 6. DETAILED DESCRIPTION

[0053] All technical and scientific terms used herein are consistent with the meanings commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for describing specific embodiments and are not intended to limit the present invention. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0054] The principle of the present invention is as follows: In the process of preparing perovskite solar cells, monomer molecules of different concentrations are added to the perovskite precursor solution, or before spin coating the perovskite precursor solution, monomer molecule solutions of different concentrations are first spin coated. The ester functional groups contained in the monomer molecules can affect the Pb in the perovskite. 2+ It can also form coordination bonds with SnO2, reduce oxygen vacancies on the surface of SnO2, and act as a Lewis base. In addition, the monomer molecules can also form coordination bonds with the under-coordinated Pb at the interface of the perovskite buried bottom. 2+ The formation of coordination bonds synergistically affects the formation and concentration of vacancy defects in perovskite, regulates the vacancy defects in perovskite crystals, thereby affecting charge transfer and carrier lifetime, and greatly increases the opening voltage V oc and filling factor FF, ultimately improving the photoelectric conversion efficiency of perovskite solar cells.

[0055] The above monomer molecules come from Figure 1 (a)~ Figure 1The product of the reaction of any one of the precursor molecules in (c) with any one of the inorganic salts such as cesium carbonate (Cs2CO3), potassium carbonate (K2CO3), sodium carbonate (Na2CO3), potassium hydroxide (KOH), sodium hydroxide (NaOH), etc., the structural formula of the reaction product is as follows Figure 2 (a)~ Figure 2 as shown in (c).

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

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

[0058] The monomer molecule 1 can be represented by the structural formula Figure 1 The precursor molecule 1 shown in (a) is reacted with cesium carbonate to obtain the precursor molecule 1. The structural formula of the precursor molecule 1 is:

[0059]

[0060] The monomer molecule 2 can be represented by the structural formula Figure 1 The precursor molecule 2 shown in (b) is reacted with potassium carbonate to obtain the precursor molecule 2. The structural formula of the precursor molecule 2 is:

[0061]

[0062] The monomer molecule 3 can be represented by the structural formula Figure 1 The precursor molecule 3 shown in (c) is reacted with sodium carbonate to obtain the precursor molecule 3. The structural formula of the precursor molecule 3 is:

[0063]

[0064] Example 1

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

[0066] Step 1: After washing the ITO conductive glass with deionized water, isopropanol and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 for 4 hours under heating at 150 ° C to obtain a 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 a monomer molecule 1 with a concentration of 1 mg / mL) and 100 μL of DMSO, stir and dissolve for 12 hours, and then filter to obtain precursor solution I. Spin 50 μL of precursor solution I on the surface of the electron transport layer, with a spin coater speed of 1500 r / min, and pre-anneal on a hot stage at 75 ° C for 1 minute after 30 seconds. After the substrate was restored to room temperature, an organic cation solution was dripped 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 placed on a hot plate at 150°C and annealed for 15 minutes to form a perovskite light absorption layer I.

[0068] Step 3: spin-coat a 4.8 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0069] In step 4, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0070] Step 5, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

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

[0072] Example 2

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

[0074] Step 1: After washing the ITO conductive glass with deionized water, isopropyl alcohol (IPA) and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 318.32mg of cesium carbonate and 325.82mg of precursor molecule 1 and dissolve them in 2147mL of DMF, stir for 4h under heating at 150℃ to obtain monomer molecule 1 solution, and dilute its concentration to 1.5mg / mL. Weigh 691.5mg of PbI2 and dissolve it in 900μL of DMF (containing monomer molecule 1 with a concentration of 1.5mg / mL) and 100μL of DMSO, stir and dissolve for 12h, and then filter to obtain precursor solution I. Spin 60μL of precursor solution I on the surface of the electron transport layer, with the speed of the coating machine at 1500r / min, and pre-anneal for 1min on a hot stage at 75℃ after 30s. After the substrate was restored to room temperature, an organic cation solution was dripped 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 annealed on a hot plate at 150°C for 15 minutes to form a perovskite light absorption layer I.

[0076] Step 3: spin-coat a 4.8 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0077] In step 4, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0078] Step 5, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

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

[0080] Example 3

[0081] This embodiment uses a monomer molecule 1 solution containing a mass concentration of 1 mg / mL and a precursor solution II containing lead iodide but no monomer molecules to prepare a perovskite solar cell containing a 1 mg / mL monomer molecule 1 passivation layer. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged in sequence from bottom to top. The specific steps are as follows:

[0082] Step 1: After washing the ITO conductive glass with deionized water, isopropanol and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 for 4 h at 150°C to obtain a monomer molecule 1 solution, and dilute its concentration to 1 mg / mL. Take 50 μL of the monomer molecule 1 solution and spin-coat it on 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, stir and dissolve for 12 hours, then filter to obtain precursor solution II, spin-coat 70 μL of precursor solution II on the surface of the passivation layer of monomer molecule 1, the speed of the gelling machine is 1500 r / min, and pre-anneal for 1 minute on a hot plate at 75°C after 30 seconds. After that, after the substrate is restored to room temperature, an organic cation solution is added 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; the substrate is annealed on a hot plate at 150°C for 15 minutes to form a perovskite light absorption layer II.

[0085] Step 4: spin-coat a 4.5 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0086] In step 5, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0087] Step 6, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

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

[0089] Example 4

[0090] In this embodiment, a perovskite solar cell containing a passivation layer of 2.1 mg / mL monomer molecule 1 is prepared by using a solution containing a monomer molecule 1 with a mass concentration of 2.1 mg / mL and a precursor solution II containing lead iodide but no monomer molecule. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged in sequence from bottom to top. The specific steps are as follows:

[0091] Step 1: After washing the ITO conductive glass with deionized water, isopropanol and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 for 4 h at 150°C, filter to obtain a monomer molecule solution, and dilute its concentration to 2.1 mg / mL. Take 90 μL of the monomer molecule 1 solution and spin-coat it on 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 DMF and 100 μL DMSO, stir and dissolve for 10 hours, and then filter to obtain precursor solution II. Spin 80 μL of precursor solution II on the surface of the passivation layer of monomer molecule 1, and the speed of the coating machine is 1500 r / min. After 30 seconds, pre-anneal for 1 minute on a hot plate at 75°C. After that, after the substrate is restored to room temperature, an organic cation solution is added 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; the substrate is annealed on a hot plate at 150°C for 10 minutes to form a perovskite light absorption layer II.

[0094] Step 4: spin-coat a 4 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0095] In step 5, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0096] Step 6, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

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

[0098] Example 5

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

[0100] Step 1: After washing the ITO conductive glass with deionized water, isopropanol and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 potassium carbonate and 138 mg precursor molecule 2 and dissolve them in 2220 mL DMF, stir for 4 h under heating at 150 ° C to obtain a monomer molecule 2 solution, and dilute its concentration to 1 mg / mL. Weigh 691.5 mg of PbI2 and dissolve it in 900 μL DMF (containing a monomer molecule 2 with a concentration of 1 mg / mL) and 100 μL DMSO, stir and dissolve for 12 h, and then filter to obtain a precursor solution I. Spin 90 μL of the precursor solution I on the surface of the electron transport layer, with a coating machine speed of 1500 r / min, and pre-anneal on a hot stage at 75 ° C for 1 min after 30 s. After the substrate was restored to room temperature, an organic cation solution was dripped 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 placed on a hot plate at 150°C and annealed for 15 minutes to form a perovskite light absorption layer I.

[0102] Step 3: spin-coat a 3.5 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0103] In step 4, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0104] Step 5, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

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

[0106] Example 6

[0107] In this embodiment, a perovskite solar cell containing a passivation layer of 0.5 mg / mL monomer molecule 3 is prepared by using a solution containing a monomer molecule 3 with a mass concentration of 0.5 mg / mL and a precursor solution II containing lead iodide but no monomer molecule. The functional layer of the perovskite solar cell obtained in this embodiment is mainly composed of a monomer molecule passivation layer and a perovskite light absorption layer II arranged in sequence from bottom to top. The specific steps are as follows:

[0108] Step 1: After washing the ITO conductive glass with deionized water, isopropanol and ethanol solution in sequence, blow it dry with nitrogen and treat it with a UV ozone instrument for 20 minutes. Mix a 12% SnO2 solution with deionized water in a volume ratio of 3:1 and ultrasonically treat it for 20 minutes. Spin-coat the prepared SnO2 on 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 for 4 h at 150°C to obtain a monomer molecule 3 solution, and dilute its concentration to 1 mg / mL. Take 50 μL of the monomer molecule 3 solution and spin-coat it on 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, stir and dissolve for 12 hours, then filter to obtain precursor solution II, spin-coat 100 μL of precursor solution II on the surface of the passivation layer of monomer molecule 3, the speed of the gelling machine is 1500 r / min, and pre-anneal for 1 minute on a hot plate at 75°C after 30 seconds. After that, after the substrate is restored to room temperature, an organic cation solution is added 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; the substrate is annealed on a hot plate at 150°C for 15 minutes to form a perovskite light absorption layer II.

[0111] Step 4: spin-coat a 4.5 mg / mL phenethylammonium iodide (PEAI) passivation layer on the substrate surface.

[0112] In step 5, an acetonitrile solution containing 4-tert-butylpyridine (tBP) and Li-TFSI and a chlorobenzene solution of Spiro-OMeTAD are spin-coated on the perovskite substrate as a hole transport layer.

[0113] Step 6, placing the substrate in an evaporator, first evaporating 4.5 nm of molybdenum trioxide, and then evaporating 80 nm of silver as a back electrode.

[0114] The photoelectric conversion efficiency of the perovskite solar cell obtained in this example 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 are 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, no monomer molecule 1 is 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 does not have step 2, and directly performs step 3.

[0122] Comparative Example 4

[0123] The difference between this comparative example and Example 4 is that this comparative example does not have step 2, and directly performs step 3.

[0124] Comparative Example 5

[0125] The difference between this comparative example and Example 5 is that in step 2, no monomer molecules are 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 does not have step 2, and directly performs step 3.

[0128] The following is a JV curve test and photovoltaic parameter statistics of the perovskite solar cells obtained using Examples 1 to 6 of the present invention and Comparative Examples 1 to 6, respectively. The process and results are as follows:

[0129] 1. JV curve test

[0130] The above-mentioned battery uses silver as the back battery. When performing the JV test, the instrument calibration and the formal assembly method of the perovskite solar cell device are: first calibrate the Keithley instrument using a standard silicon-based solar cell, then place the prepared battery in it, the back electrode contacts the probe in the test battery mold, and the positive and negative electrodes of the test battery mold are connected to the positive and negative electrodes of the calibrated Keithley instrument respectively. Given a voltage value of 1.2V, the battery is tested for the JV curve.

[0131] Figure 3 , Figure 5 , Figure 7 , Fig. 9 , Fig.11 and Fig.13 They are respectively the JV curves of the perovskite solar cell (Example 1) in which the perovskite precursor solution I contains 0.9 mg / mL monomer molecule 1 and the comparison sample (Comparative Example 1), the JV curves of the perovskite solar cell (Example 2) and the comparison sample (Comparative Example 2) in which the perovskite precursor solution I contains 1.35 mg / mL monomer molecule 1, the JV curves of the perovskite solar cell (Example 3) and the comparison sample (Comparative Example 3) containing a passivation layer of 1 mg / mL monomer molecule 1, the JV curves of the perovskite solar cell (Example 4) and the comparison sample (Comparative Example 4) containing a passivation layer of 2.1 mg / mL monomer molecule 1, the JV curves of the perovskite solar cell (Example 5) and the comparison sample (Comparative Example 2) in which the perovskite precursor solution I contains 1 mg / mL monomer molecule 2, and the JV curves of the perovskite solar cell (Example 6) and the comparison sample (Comparative Example 6) containing a passivation layer of 0.5 mg / mL monomer molecule 1.

[0132] from Figure 3 It can be seen that the photoelectric conversion efficiency of the perovskite solar cell prepared by adding monomer molecule 1 to the perovskite precursor solution is as high as 24.2% (Example 1), and the corresponding current density Jsc, opening voltage Voc and filling factor FF are 25.49 mA / cm 2 , 1.147V and 82.79%. The photoelectric conversion efficiency of Example 1 is improved by 11.82% compared with that of Comparative Example 1.

[0133] from Figure 5 It can be seen that the photoelectric conversion efficiency of the perovskite solar cell (Example 3) containing a passivation layer of 1 mg / mL monomer molecule is the highest at 23.71%, and the corresponding current density Jsc, opening voltage Voc and fill factor FF are 25.40 mA / cm 2 , 1.134V and 82.30%. The photoelectric conversion efficiency of Example 3 is improved by 8.26% compared with that of Comparative Example 3.

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

[0135] Figure 4 , Figure 6 , Figure 8 , Fig.10 , Fig.12 and Fig.14They are respectively photovoltaic parameter statistical graphs of a perovskite solar cell (Example 1) in which the perovskite precursor solution contains 0.9 mg / mL of monomer molecule 1 and a comparison sample (Comparative Example 1), photovoltaic parameter statistical graphs of a perovskite solar cell (Example 2) in which the perovskite precursor solution contains 1.35 mg / mL of monomer molecule 1 and a comparison sample (Comparative Example 2), photovoltaic parameter statistical graphs of a perovskite solar cell (Example 3) and a comparison sample (Comparative Example 3) containing a passivation layer of 1 mg / mL of monomer molecule 1, and photovoltaic parameter statistical graphs of a perovskite solar cell (Example 4) and a comparison sample (Comparative Example 4) containing a passivation layer of 2.1 mg / mL of monomer molecule 1, photovoltaic parameter statistical graphs of a perovskite solar cell (Example 5) and a comparison sample (Comparative Example 2) in which the perovskite precursor solution I contains 1 mg / mL of monomer molecule 2, and photovoltaic parameter statistical graphs of a perovskite solar cell (Example 6) and a comparison sample (Comparative Example 6) containing a passivation layer of 0.5 mg / mL of monomer molecule 1.

[0136] from Figure 4 It can be seen that the opening voltage V of Example 1 oc The filling factor FF has been significantly improved, which may be because the ester functional group contained in monomer molecule 1 affects the Pb in perovskite 2+ It can also form a coordination bond with SnO2, reduce the oxygen vacancies on the surface of SnO2, and act as a Lewis base. It can also form a coordination bond with the under-coordinated Pb at the interface of the perovskite buried 2+ Forming coordination bonds synergistically.

[0137] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. It should be noted that for researchers in the field, the present invention is intended to cover any variation, use or adaptive change of the present application, which follows the general principles of the present application and includes common knowledge or conventional technical means in the technical field that are not disclosed in the present application.

Claims

1. A perovskite solar cell, characterized in that: The perovskite solar cell comprises a conductive glass substrate layer, an electron transport layer, a functional layer, a passivation layer, a hole transport layer and a metal electrode layer arranged in sequence from bottom to top; the functional layer comprises monomer molecules, and the monomer molecules comprise phenolphthalein and phenolphthalein derivatives containing a Cardo ring; The functional layer is mainly composed of a perovskite light absorption layer I, and the perovskite light absorption layer I 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 in sequence from bottom to top, and 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 not containing monomer molecules.

2. The perovskite solar cell according to claim 1, characterized in that: The monomer molecule is 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, 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 one of the following structural formulas:

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

4. The perovskite solar cell according to claim 3, characterized in that: The organic cation solution contains formamidine hydroiodide with a mass concentration of 50-100 mg / mL, methylammonium iodide with a mass concentration of 5-10 mg / mL, and methylammonium chloride with a mass concentration of 5-10 mg / mL.

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

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

7. A method for preparing a perovskite solar cell according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1) coating an electron transport layer on the conductive glass substrate layer; S2) coating a functional layer on the electron transport layer; S3) coating a passivation layer on the functional layer; S4) coating a hole transport layer on the passivation layer; S5) evaporating a metal electrode on the hole transport layer to obtain the perovskite solar cell.

8. The method for preparing a perovskite solar cell according to claim 7, characterized in that: The step S2) is specifically as follows: spin coating the precursor solution I on the electron transport layer, and then sequentially performing pre-annealing, dripping the organic cationic 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 to 3 mg / mL and lead iodide or lead bromide with a molar concentration of 1.2 to 1.6 mol / L; Alternatively, the step S2) is specifically as follows: spin coating a monomer molecule solution and a precursor solution II on the electron transport layer in sequence, and then performing pre-annealing, dripping an organic cation solution and annealing in sequence to form a functional layer on the electron transport layer; the monomer molecule solution contains monomer molecules with a mass concentration of 0.5 to 3 mg / mL; the precursor solution II contains lead iodide or lead bromide with a molar concentration of 1.2 to 1.6 mol / L.

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

10. The method for preparing a perovskite solar cell according to claim 7, characterized in that: The step S3) is specifically as follows: coating a passivation layer stock solution on the functional layer to form a passivation layer; the passivation layer stock solution contains a passivation layer material with a concentration of 4 to 6 mg / mL, the passivation layer material includes phenethylamine iodide and / or phenethylamine iodide derivatives, and the phenethylamine iodide derivatives include one or more of pF-PEAI, oF-PEAI and mF-PEAI.

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