Perovskite solar cell and preparation method thereof, photovoltaic module

Abstract

This invention discloses a perovskite solar cell, its fabrication method, and a photovoltaic module. The fabrication method includes the following steps: S1, mixing a self-assembled monomolecular material with an organic solvent to obtain solution I; mixing solution I with a pyrrolidone compound to obtain solution II; coating solution II onto the surface of a conductive substrate; annealing solution I to obtain a hole transport layer; S2, coating a perovskite precursor solution onto the surface of the hole transport layer and annealing solution II to obtain a perovskite thin film; S3, sequentially fabricating an electron transport layer, a hole blocking layer, and an electrode on the surface of the perovskite thin film to obtain a perovskite solar cell; wherein the pyrrolidone compound is selected from at least one of 2-pyrrolidone, N-methylpyrrolidone, or N-ethylpyrrolidone. This method avoids the use of antisolvents and effectively improves the thin film quality and device performance.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a perovskite solar cell and its preparation method, as well as a photovoltaic module. Background Technology

[0002] Perovskite solar cells represent a significant breakthrough in photovoltaic technology in recent years. Perovskite materials possess unique photoelectric properties, including high absorption coefficients, long carrier diffusion lengths, and tunable band gaps, making them potential solar cell materials with high energy conversion efficiency. Since the first report of perovskite solar cells in 2009, their energy conversion efficiency has rapidly increased from an initial 3.8% to over 26% currently, approaching the efficiency of silicon-based solar cells. This significant efficiency improvement is mainly attributed to material optimization, process improvements, and device structure innovations. The general formula for perovskite materials is ABX3, where A is an organic or inorganic cation (such as methylammonium, formamidinium, or cesium ions), B is a metal cation (such as lead or tin), and X is a halide anion (such as iodine, bromine, or chlorine). The unique crystal structure and chemical composition of perovskite enable it to effectively absorb sunlight and generate photogenerated charges, thereby improving the conversion efficiency of solar cells.

[0003] The main reason hindering the large-scale application of perovskite solar cells is the limitation of perovskite thin film preparation process. Traditional perovskite thin film preparation requires further treatment with antisolvents to obtain perovskite thin films with better uniformity. However, the use of antisolvents not only limits the size of perovskite preparation, but the toxicity of antisolvents is also one of the main reasons.

[0004] Therefore, there is an urgent need to develop a method for fabricating perovskite solar cells without anti-solvents. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a method for fabricating perovskite solar cells; this method avoids the use of anti-solvents and effectively improves the thin film quality and device performance.

[0006] A second aspect of the present invention also provides a perovskite solar cell.

[0007] A third aspect of the present invention also provides a photovoltaic module.

[0008] A method for fabricating a perovskite solar cell according to a first aspect embodiment of the present invention includes the following steps:

[0009] S1. Mix self-assembled single-molecule material (SAM) with an organic solvent to obtain solution I; mix solution I with a pyrrolidone compound to obtain solution II; coat solution II on the surface of a conductive substrate; anneal solution I to obtain the hole transport layer;

[0010] S2. The perovskite precursor solution is coated on the surface of the hole transport layer and then annealed (II) to obtain the perovskite film.

[0011] S3. An electron transport layer, a hole blocking layer, and an electrode are sequentially fabricated on the surface of a perovskite thin film to obtain a perovskite solar cell.

[0012] The pyrrolidone compound is selected from at least one of 2-pyrrolidone, N-methylpyrrolidone, or N-ethylpyrrolidone.

[0013] The preparation method according to embodiments of the present invention has at least the following beneficial effects:

[0014] In related technologies, self-assembled single-molecule materials are directly used as hole transport layers to prepare anti-solvent-free perovskite solar cells. However, due to the mismatch between the homo energy levels of the self-assembled single-molecule materials and the homo energy levels of the anti-solvent-free perovskite films, hole transport is hindered, resulting in significant open-circuit voltage loss.

[0015] This invention employs a mixture of pyrrolidone compounds and self-assembled monomolecules. By combining the carbonyl groups on the pyrrolidone compounds with the self-assembled monomolecules, the homo energy level is lowered, thereby enabling tunable hole transport layer energy levels. This allows for the fabrication of high-performance, anti-solvent-free perovskite solar cells.

[0016] According to some embodiments of the present invention, the volume ratio of solution I to the pyrrolidone compound is 100:(0.5-3). When the volume ratio of the pyrrolidone compound is too low, the improvement effect is not significant; when the volume ratio of the pyrrolidone compound is too high, it will affect the aggregation of SAM, thereby reducing conductivity and hole transport capacity. Therefore, when the volume ratio of solution I to the pyrrolidone compound is within the range defined by the present invention, high-performance perovskite solar cells can be fabricated.

[0017] According to some embodiments of the present invention, the mass concentration of solution I is 0.3 mg / mL to 1 mg / mL.

[0018] According to some embodiments of the present invention, the self-assembled monomolecular material is selected from at least one of ME-4PACZ ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid), MEO-2PACZ ((2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid), or 4PADCB ([4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid).

[0019] According to some embodiments of the present invention, the components of the perovskite precursor solution are selected from FA. x Cs (1-x) PbI3; where x is 0.83–0.95. This results in a more stable crystal structure for perovskites.

[0020] According to some embodiments of the present invention, in step S1, the annealing temperature is 80°C to 100°C.

[0021] According to some embodiments of the present invention, in step S1, the annealing time is 10 min to 30 min.

[0022] According to some embodiments of the present invention, in step S2, the annealing temperature is 130°C to 150°C.

[0023] According to some embodiments of the present invention, in step S2, the annealing time of step II is 10 min to 30 min.

[0024] According to some embodiments of the present invention, the material of the electron transport layer is selected from C60 or PCBM.

[0025] According to some embodiments of the present invention, the material of the hole blocking layer is selected from at least one of BCP, acetylacetonate, and TPBi:1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene.

[0026] According to some embodiments of the present invention, the material of the electrode is selected from gold, copper or silver.

[0027] According to some embodiments of the present invention, the thickness of the electron transport layer is 30–50 nm.

[0028] According to some embodiments of the present invention, the thickness of the barrier layer is 6 to 10 nm.

[0029] According to some embodiments of the present invention, the thickness of the electrode is 100-200 nm.

[0030] According to some embodiments of the present invention, the conductive substrate includes an indium tin oxide conductive glass substrate (ITO) or a fluorine-doped tin dioxide conductive glass substrate (FTO).

[0031] According to some embodiments of the present invention, the conductive substrate is further pretreated before use.

[0032] According to some embodiments of the present invention, the pretreatment steps include cleaning, ultrasonication, and ultraviolet ozone irradiation.

[0033] A perovskite solar cell according to a second aspect of the present invention is prepared by the preparation method described in the first aspect of the present invention.

[0034] A third aspect of the present invention provides a photovoltaic module, including the perovskite solar cell described in the second aspect of the present invention.

[0035] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0036] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0037] Figure 1 This is a JV curve diagram of the perovskite solar cells prepared in the embodiments and comparative examples of the present invention.

[0038] Figure 2 This is the infrared spectrum of the self-assembled single-molecule material according to an embodiment of the present invention. Detailed Implementation

[0039] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0040] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0041] Example 1

[0042] This example provides a perovskite solar cell, the fabrication method of which is as follows:

[0043] Pretreatment of conductive glass substrate: (1) Clean the ITO conductive glass substrate with conductive glass cleaner, deionized water and ethanol, and sonicate at 99% power for 30 minutes to obtain a clean ITO conductive glass substrate.

[0044] (2) Take a clean ITO conductive glass substrate and irradiate it in an ultraviolet ozone cleaner for 30 minutes.

[0045] Perovskite precursor solution: Take 461 mg PbI2, 142.8 mg FAI, 27.8 mg PbCl2 and 44.2 mg CsI2 and stir them in a mixed solution of DMF:NMP = 500:96. Stir for 2 hours and let stand to obtain a homogeneous perovskite precursor solution.

[0046] S1. Take 0.3 mg of ME-4PACZ and stir it in 1 mL of isopropanol solution for 30 min. Let it stand to obtain a homogeneous SAM molecular solution I. Take 10 μL of 2-pyrrolidone and add it to SAM molecular solution I. Continue stirring for 30 min to obtain solution II.

[0047] Solution II was used to prepare a monolayer on an ITO conductive substrate by spin coating at a speed of 4000 rpm for 30 s. The layer was then annealed on a heating stage at 100 °C for 10 min to obtain the hole transport layer.

[0048] S2. Take the perovskite precursor solution and use spin coating to prepare a solvent-free perovskite film on the hole transport layer. The spin coating speed is 5000 rpm and the spin coating time is 50 s. Then, anneal at 150℃ for 10 min to obtain a solvent-free perovskite film.

[0049] S3. Place the perovskite thin film in a vacuum evaporation chamber and sequentially deposit C60 with a thickness of 40 nm, BCP with a thickness of 8 nm, and Cu with a thickness of 100 nm; thus obtaining a solar perovskite cell.

[0050] Example 2

[0051] This example provides a perovskite solar cell, the fabrication method of which is as follows:

[0052] Pretreatment of conductive glass substrate: (1) Clean the ITO conductive glass substrate with conductive glass cleaner, deionized water and ethanol, and sonicate at 99% power for 30 minutes to obtain a clean ITO conductive glass substrate.

[0053] (2) Take a clean ITO conductive glass substrate and irradiate it in an ultraviolet ozone cleaner for 30 minutes.

[0054] Perovskite precursor solution: Take 461 mg PbI2, 142.8 mg FAI, 27.8 mg PbCl2 and 44.2 mg CsI2 and stir them in a mixed solution of DMF:NMP = 500:96. Stir for 2 hours and let stand to obtain a homogeneous perovskite precursor solution.

[0055] S1. Take 0.3 mg of ME-4PACZ and shake and stir it in 1 mL of isopropanol solution. Stir for 30 min and let it stand to obtain a homogeneous SAM molecular solution I. Take 10 μL of N-methylpyrrolidone and add it to SAM molecular solution I. Continue stirring for 30 min to obtain solution II.

[0056] Solution II was used to prepare a monolayer on an ITO conductive substrate by spin coating at a speed of 4000 rpm for 30 s. The layer was then annealed on a heating stage at 100 °C for 10 min to obtain the hole transport layer.

[0057] S2. Take the perovskite precursor solution and use spin coating to prepare a solvent-free perovskite film on the hole transport layer. The spin coating speed is 5000 rpm and the spin coating time is 50 s. Then, anneal at 150℃ for 10 min to obtain a solvent-free perovskite film.

[0058] S3. Place the perovskite thin film in a vacuum evaporation chamber and sequentially deposit C60 with a thickness of 40 nm, BCP with a thickness of 8 nm, and Cu with a thickness of 100 nm; thus obtaining a solar perovskite cell.

[0059] Example 3

[0060] This example provides a perovskite solar cell, the fabrication method of which is as follows:

[0061] Pretreatment of conductive glass substrate: (1) Clean the ITO conductive glass substrate with conductive glass cleaner, deionized water and ethanol, and sonicate at 99% power for 30 minutes to obtain a clean ITO conductive glass substrate.

[0062] (2) Take a clean ITO conductive glass substrate and irradiate it in an ultraviolet ozone cleaner for 30 minutes.

[0063] Perovskite precursor solution: Take 461 mg PbI2, 142.8 mg FAI, 27.8 mg PbCl2 and 44.2 mg CsI2 and stir them in a mixed solution of DMF:NMP = 500:96. Stir for 2 hours and let stand to obtain a homogeneous perovskite precursor solution.

[0064] S1. Take 0.3 mg of ME-4PACZ and shake and stir it in 1 mL of isopropanol solution. Stir for 30 min and let it stand to obtain a homogeneous SAM molecular solution I. Take 10 μL of N-ethylpyrrolidone and add it to SAM molecular solution I. Continue stirring for 30 min to obtain solution II.

[0065] Solution II was used to prepare a monolayer on an ITO conductive substrate by spin coating at a speed of 4000 rpm for 30 s. The layer was then annealed on a heating stage at 100 °C for 10 min to obtain the hole transport layer.

[0066] S2. Take the perovskite precursor solution and use spin coating to prepare a solvent-free perovskite film on the hole transport layer. The spin coating speed is 5000 rpm and the spin coating time is 50 s. Then, anneal at 150℃ for 10 min to obtain a solvent-free perovskite film.

[0067] S3. Place the perovskite thin film in a vacuum evaporation chamber and sequentially deposit C60 with a thickness of 40 nm, BCP with a thickness of 8 nm, and Cu with a thickness of 100 nm; thus obtaining a solar perovskite cell.

[0068] Example 4

[0069] This example provides a perovskite solar cell, which is prepared in a manner that is basically the same as in Example 1, except that the volume ratio of solution I to pyrrolidone compounds is 100:3.

[0070] Example 5

[0071] This example provides a perovskite solar cell, the preparation method of which is basically the same as that in Example 1, except that the volume ratio of solution I to pyrrolidone compounds is 100:0.5.

[0072] Example 6

[0073] This example provides a perovskite solar cell, which is prepared in a manner that is basically the same as that in Example 1, except that the volume ratio of solution I to pyrrolidone compounds is 100:5.

[0074] Example 7

[0075] This example provides a perovskite solar cell, the preparation method of which is basically the same as that in Example 1, except that the volume ratio of solution I to pyrrolidone compounds is 100:0.1.

[0076] Comparative Example 1

[0077] Comparative Example 1 provides a perovskite solar cell, the preparation method of which is as follows:

[0078] Pretreatment of conductive glass substrate: (1) Clean the ITO conductive glass substrate with conductive glass cleaner, deionized water and ethanol, and sonicate at 99% power for 30 minutes to obtain a clean ITO conductive glass substrate.

[0079] (2) Take a clean ITO conductive glass substrate and irradiate it in an ultraviolet ozone cleaner for 30 minutes.

[0080] Perovskite precursor solution: Take 461 mg PbI2, 142.8 mg FAI, 27.8 mg PbCl2 and 44.2 mg CsI2 and stir them in a mixed solution of DMF:NMP = 500:96. Stir for 2 hours and let stand to obtain a homogeneous perovskite precursor solution.

[0081] S1. Take 0.3 mg of ME-4PACZ and stir it in 1 mL of isopropanol solution. Stir for 30 min and let it stand to obtain a homogeneous SAM molecular solution I.

[0082] A monolayer was prepared on an ITO conductive substrate using spin coating with SAM molecular solution I at a spin coating speed of 4000 rpm for 30 s. The substrate was then annealed on a 100℃ heating stage for 10 min to obtain a hole transport layer.

[0083] S2. Take the perovskite precursor solution and use spin coating to prepare a solvent-free perovskite film on the hole transport layer. The spin coating speed is 5000 rpm and the spin coating time is 50 s. Then, anneal at 150℃ for 10 min to obtain a solvent-free perovskite film.

[0084] S3. Place the perovskite thin film in a vacuum evaporation chamber and sequentially deposit C60 with a thickness of 40 nm, BCP with a thickness of 8 nm, and Cu with a thickness of 100 nm; thus obtaining a solar perovskite cell.

[0085] Comparative Example 2

[0086] Comparative Example 2 provides a perovskite solar cell, the preparation method of which is as follows:

[0087] Pretreatment of conductive glass substrate: (1) Clean the ITO conductive glass substrate with conductive glass cleaner, deionized water and ethanol, and sonicate at 99% power for 30 minutes to obtain a clean ITO conductive glass substrate.

[0088] (2) Take a clean ITO conductive glass substrate and irradiate it in an ultraviolet ozone cleaner for 30 minutes.

[0089] 462 mg PbI2, 142.8 mg FAI, 27.8 mg PbCl2, and 44.2 mg CsI2 of perovskite precursor materials were mixed with 500 mL of precursor solvent I DMF, 96 μL of precursor solvent II NMP, and 0.5 mg of monomolecular self-assembled material ME-4PACZ. The mixture was stirred with vibration for 2 h to obtain a perovskite precursor solution.

[0090] The precursor solution was prepared on a conductive glass substrate ITO using a spin coating method with a spin coating speed of 5000 rpm and a spin coating time of 50 s. Then, it was annealed at 150 °C for 10 min to obtain a solvent-free perovskite film.

[0091] A perovskite thin film was placed in a vacuum evaporation chamber, and C60 with a thickness of 40 nm, BCP with a thickness of 8 nm, and Cu with a thickness of 100 nm were deposited sequentially to obtain a solar cell.

[0092] Performance testing

[0093] Infrared spectroscopy was performed on solution II prepared in step S1 of Examples 1-3 of the present invention and SAM molecular solution I in Comparative Example 1. The results are as follows: Figure 2 As shown in the figure, the peak position of transmittance at the position of the yellow line in Comparative Example 1 and Examples 1, 2, and 3 all show a certain shift, indicating that the pyrrolidone additives interact with each other after being added to the SAM solution.

[0094] The perovskite solar cells prepared in Examples 1-7 and Comparative Example 1 of this invention were subjected to JV testing. The results of Examples 1-3 and Comparative Example 1 are as follows: Figure 1 As shown in Table 1, the data is as follows.

[0095] Table 1 Examples 1-7 and Comparative Examples 1-2

[0096]

[0097] As can be seen from the data in Table 1, the perovskite solar cells prepared in Examples 1-3 of this invention have higher open-circuit voltage, photoelectric conversion efficiency, fill factor, and short-circuit current than the perovskite solar cell in Comparative Example 1. This indicates that the present invention uses pyrrolidone compounds to mix with self-assembled single-molecule materials; by combining the carbonyl groups on the pyrrolidone compounds with the self-assembled single-molecule materials, the HOMO energy level is reduced, thereby achieving tunable hole transport layer energy level; thus, a high-performance anti-solvent-free perovskite solar cell is prepared.

[0098] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: S1. Mix the self-assembled monomolecular material with an organic solvent to obtain solution I; mix solution I with a pyrrolidone compound to obtain solution II; coat solution II on the surface of a conductive substrate; anneal solution I to obtain the hole transport layer. S2. The perovskite precursor solution is coated on the surface of the hole transport layer and then annealed (II) to obtain the perovskite film. S3. An electron transport layer, a hole blocking layer, and an electrode are sequentially prepared on the surface of a perovskite thin film to obtain a perovskite solar cell. The pyrrolidone compound is selected from at least one of 2-pyrrolidone, N-methylpyrrolidone, or N-ethylpyrrolidone; the volume ratio of solution I to the pyrrolidone compound is 100:(0.5~3); the mass concentration of solution I is 0.3 mg / mL~1 mg / mL; the self-assembled monomolecule material is selected from at least one of ME-4PACZ, MEO-2PACZ, or 4PADCB.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The components of the perovskite precursor solution are selected from FA. x Cs (1-x) PbI3; where x is 0.83~0.

95.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step S1, the annealing temperature is 80℃~100℃.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step S2, the annealing temperature II is 130℃~150℃.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step S2, the annealing time for step II is 10 min to 30 min.

6. A perovskite solar cell, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

7. A photovoltaic module, characterized in that, Including the perovskite solar cell of claim 6.

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