Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. The preparation method comprises the following steps: S1, preparing an inorganic halogenated metal film on the surface of a hole transport layer of a conductive substrate; s2, coating the composite solution on the surface of an inorganic halogenated metal film through a spin-coating method, and annealing to obtain a perovskite film; the composite solution comprises an organic amine salt solution and guanidyl small molecules; the organic amine salt solution comprises at least one of formamidine hydroiodate, methylamine chloride, formamidine hydrobromide, methylamine iodide or methylamine bromide; s3, preparing an electron transport layer on the surface of the perovskite thin film; and evaporating a metal electrode on the surface of the electron transport layer to obtain the perovskite solar cell. According to the invention, the perovskite solar cell is prepared by a dry-wet two-step conversion method; the guanidyl small molecules enter the thin film through diffusion, the growth quality of the thin film is improved, and the photoelectric conversion efficiency and the open-circuit voltage of a dry-wet two-step conversion method are improved.

Description

Technical Field

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

[0002] Perovskite solar cells have developed rapidly in the past decade, and their photoelectric conversion efficiency has exceeded 26%, making them an important player in the next generation of photovoltaic cells. Currently, high-efficiency perovskite solar cells are generally prepared by configuring perovskite precursor solution through a one-step wet method. However, this method requires a large amount of harmful organic solvents and has high requirements for the purity of the raw materials. In addition, the dry-wet two-step conversion method can also be used to prepare perovskite films, but the photoelectric efficiency of perovskite solar cells prepared based on the dry-wet two-step method is still lower than that prepared by the one-step wet method.

[0003] Therefore, it is necessary to develop a new dry-wet two-step method to prepare perovskite solar cells. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first aspect of the present invention provides a method for preparing a perovskite solar cell, which can effectively improve the photoelectric conversion efficiency of the perovskite cell prepared by the dry-wet two-step method.

[0005] The second aspect of the present invention also provides a perovskite solar cell.

[0006] A method for preparing a perovskite solar cell according to an embodiment of the first aspect of the present invention comprises the following steps:

[0007] S1. preparing an inorganic halogenated metal thin film on the surface of a hole transport layer of a conductive substrate;

[0008] S2, coating the composite solution on the surface of the inorganic halide metal film by spin coating, and annealing to obtain a perovskite film; the composite solution comprises an organic amine salt solution and a guanidine small molecule; the components of the organic amine salt solution include at least one of formamidine hydroiodide, methylamine chloride, formamidine hydrobromide, methylamine iodide or methylamine bromide;

[0009] S3, preparing an electron transport layer on the surface of the perovskite film; evaporating a metal electrode on the surface of the electron transport layer to obtain a perovskite solar cell;

[0010] Wherein, the structural formula of the guanidine small molecule is as follows:

[0011]

[0012] X is selected from halogen;

[0013] R is selected from C 1～3an alkylene group, a phenyl group, a phenyl group substituted by a halogen group, or a naphthyl group.

[0014] The preparation method according to the embodiment of the present invention has at least the following beneficial effects:

[0015] The present invention adopts a dry-wet two-step conversion method to prepare a perovskite solar cell. First, an inorganic halide metal salt is evaporated by thermal evaporation to form an inorganic halide metal film on a substrate, and then an organic ammonium salt solution containing guanidine small molecules is coated on the surface of the halide metal film by spin coating. At the solid-liquid interface, the guanidine small molecules interact electrostatically with the inorganic halide metal in the film and the organic ammonium salt in the solution through guanidine groups and acid radical groups, respectively, and help to quickly form a guanidine small molecule·halide metal salt·organic ammonium salt diffusion layer under the action of an organic pure solvent as a medium. In the annealing stage, the organic ammonium salt on the surface of the film layer quickly diffuses into the inorganic halide metal film through the diffusion layer, and reacts with the inorganic halide metal salt to form a perovskite light absorption layer. The guanidine small molecules increase the diffusion rate by virtue of the interaction with the inorganic halide metal and the organic ammonium salt, and enhance the binding energy between the inorganic halide metal and the organic ammonium salt, so that the diffusion reaction is more uniform and the crystallinity of the film is improved.

[0016] According to some embodiments of the present invention, R is selected from one of the following structural formulas:

[0017] in, Indicates the connection site.

[0018] According to some embodiments of the present invention, the composition of the inorganic halogenated metal film includes at least one of PbI2, PbBr2, PbCl2, CsBr, CsI or CsCl.

[0019] According to some embodiments of the present invention, the concentration of the guanidine small molecule is 2-6 mM.

[0020] According to some embodiments of the present invention, the concentration of the guanidine small molecule is 2-4 mM.

[0021] According to some embodiments of the present invention, in step S2, the annealing temperature is 100-170°C.

[0022] According to some embodiments of the present invention, in step S2, the annealing time is 1 to 20 minutes.

[0023] According to some embodiments of the present invention, the hole transport layer comprises nickel oxide, PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), VNPB (CAS No.: 1010396-31-2), MeO-2PACz ((2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid, CAS No.: 2377770-18-6), Me-2PACz ([2-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphonic acid, CAS No.: 2996161-30-7), 2PAC At least one of MeO-4PACz ([2-(9H-carbazole-9-yl)ethyl]phosphonic acid; CAS No.: 20999-38-6), MeO-4PACz ([4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid; CAS No.: 2922526-56-3), Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid; CAS No.: 2747959-96-0) or 4PACz ([4-(9H-carbazole-9-yl)butyl]phosphonic acid, CAS No.: 20999-36-4).

[0024] According to some embodiments of the present invention, the method of preparing the electron transport layer includes an evaporation method and a deposition method.

[0025] According to some embodiments of the present invention, the material of the electron transport layer includes [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) / 2,9-dimethyl-4,7-diphenyl-o-phenanthroline (BCP), fullerene C 60 / BCP or Fullerene C 60 and atomic deposition method to prepare tin oxide combination.

[0026] According to some embodiments of the present invention, the hole transport layer is prepared by spin coating or deposition.

[0027] According to some embodiments of the present invention, the conductive base comprises a conductive glass substrate.

[0028] According to some embodiments of the present invention, the conductive substrate further comprises a pretreatment step before use.

[0029] According to some embodiments of the present invention, the pretreatment step includes: ultrasonicating the conductive substrate in a cleaning agent, ultrapure water and anhydrous ethanol for 30 minutes respectively for standby use, and performing UV-ozone treatment before use.

[0030] A perovskite solar cell provided in an embodiment according to the second aspect of the present invention is prepared by the preparation method described above.

[0031] According to some embodiments of the present invention, the thickness of the inorganic metal halide film is 200-700 nm.

[0032] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0033] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0034] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0035] Example 1

[0036] This example provides a method for preparing a perovskite solar cell, comprising the following steps:

[0037] Pretreatment: ultrasonically treat the conductive glass substrate in a cleaning agent, ultrapure water and anhydrous ethanol for 30 minutes respectively, and perform UV-ozone treatment before use;

[0038] Preparation of hole transport layer: prepare 0.5 mg / mL DMF solution of organic small molecule [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, draw 30uL and spin coat on the prepared conductive glass substrate at 3000rpm, 1500rpm / s, 30s. After spin coating, anneal at 100℃ for 10min, and obtain hole transport layer film after annealing and cooling;

[0039] S1, preparing an inorganic halogenated metal film on the surface of the obtained hole transport layer film, and using a thermal evaporation method to and Co-evaporation of PbI2 and CsBr to obtain an inorganic halide metal film with a thickness of 300nm;

[0040] S2. Prepare an organic amine salt solution: dissolve formamidine hydroiodide (29.6 mg), methylamine chloride (4.8 mg), and methylamine bromide (37.7 mg) in 1 mL of isopropanol, and add 4-guanidinobenzoic acid hydrochloride (GBAC, 2 mM) to the solution to obtain a composite solution;

[0041] The composite solution was coated on the inorganic halide metal film, the spin coating procedure was 2000rpm, 1000rpm / s, 30s, the spin coating amount was 100uL, and after the spin coating was completed, it was annealed at 150°C for 22min, and the perovskite film was obtained after annealing and cooling.

[0042] S3, 25nm C was sequentially deposited on the prepared perovskite film 60 , 6nm BCP and 110nm silver electrode, the evaporation rates are and The perovskite solar cell is obtained.

[0043] Example 2

[0044] This example provides a method for preparing a perovskite solar cell, which is basically the same as that in Example 1, except that the concentration of GBAC added to the organic ammonium salt is 4 mM, and a composite solution is obtained after mixing.

[0045] Example 3

[0046] This example provides a method for preparing a perovskite solar cell, which is basically the same as that in Example 1, except that the concentration of GBAC added to the organic ammonium salt is 6 mM, and a composite solution is obtained after mixing.

[0047] Example 4

[0048] This example provides a method for preparing a perovskite solar cell, which is basically the same as that in Example 1, except that the concentration of GBAC added to the organic ammonium salt is 8 mM, and a composite solution is obtained after mixing.

[0049] Comparative Example 1

[0050] This example provides a method for preparing a perovskite solar cell, comprising the following steps:

[0051] Pretreatment: ultrasonically treat the conductive glass substrate in a cleaning agent, ultrapure water and anhydrous ethanol for 30 minutes respectively, and perform UV-ozone treatment before use;

[0052] Preparation of hole transport layer: prepare 0.5 mg / mL DMF solution of organic small molecule [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, draw 30uL and spin coat on the prepared conductive glass substrate at 3000rpm, 1500rpm / s, 30s. After spin coating, anneal at 100℃ for 10min, and obtain hole transport layer film after annealing and cooling;

[0053] S1. Prepare an inorganic halogenated metal thin film on the surface of the obtained hole transport layer thin film, and co-evaporate PbI2 and CsBr at 1 A / s and 0.1 A / s by thermal evaporation to obtain a 300 nm inorganic halogenated metal thin film;

[0054] S2. Prepare an organic amine salt solution: dissolve formamidine hydroiodide (29.6 mg), methylamine chloride (4.8 mg), and methylamine bromide (37.7 mg) in 1 mL of isopropanol.

[0055] An organic amine salt solution was coated on the inorganic halide metal film, the spin coating procedure was 2000rpm, 1000rpm / s, 30s, the spin coating amount was 100uL, and after the spin coating was completed, annealing was performed at 150°C for 22min, and the perovskite film was obtained after annealing and cooling.

[0056] S3, 25nm C was sequentially deposited on the prepared perovskite film 60 , 6nm BCP and 110nm silver electrode, the evaporation rates are and The perovskite solar cell is obtained.

[0057] Performance Testing

[0058] The perovskite solar cells prepared in the examples of the present invention and the comparative examples were subjected to solar cell JV curve tests, and the data are shown in Table 1.

[0059] Table 1 Examples and Comparative Examples

[0060]

[0061] It can be seen from the data in Table 1 that the present invention first prepares an inorganic halide metal film, and then spin-coats an organic amine salt solution containing guanidine small molecules on the surface of the inorganic halide metal film. The perovskite film obtained by annealing and cooling has high crystal quality, reduces the defect density in the film bulk phase, and improves the open circuit voltage and photoelectric conversion efficiency of the battery.

[0062] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The steps include: S1. preparing an inorganic halogenated metal thin film on the surface of a hole transport layer of a conductive substrate; S2, coating the composite solution on the surface of the inorganic halide metal film by spin coating, and annealing to obtain a perovskite film; the composite solution comprises an organic amine salt solution and a guanidine small molecule; the components of the organic amine salt solution include at least one of formamidine hydroiodide, methylamine chloride, formamidine hydrobromide, methylamine iodide or methylamine bromide; S3, preparing an electron transport layer on the surface of the perovskite film; evaporating a metal electrode on the surface of the electron transport layer to obtain a perovskite solar cell; Wherein, the structural formula of the guanidine small molecule is as follows: X is selected from halogen; R is selected from C 1～3 an alkylene group, a phenyl group, a phenyl group substituted by a halogen group, or a naphthyl group.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The inorganic halogenated metal film comprises at least one of PbI2, PbBr2, PbCl2, CsBr, CsI or CsCl.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The concentration of the guanidine small molecule is 2-6 mM.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that: In step S2, the annealing temperature is 100-170°C.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The hole transport layer comprises at least one of nickel oxide, PTAA, VNPB, MeO-2PACz, Me-2PACz, 2PACz, MeO-4PACz, Me-4PACz or 4PACz.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The method for preparing the electron transport layer includes evaporation method and deposition method.

7. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The metal electrode includes at least one of Au, Ag, Al, Cr or Cu.

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that: In step S1, the method of preparing the inorganic halogenated metal film includes an evaporation method.

9. A perovskite solar cell, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 8.

10. The perovskite solar cell according to claim 9, characterized in that: The thickness of the inorganic halogenated metal film is 200-700 nm.

Images