Method for preparing perovskite thin film through buried bottom interface treatment and preparation methods of perovskite solar cell and perovskite / silicon laminated solar cell

Abstract

The invention belongs to the technical field of perovskite thin films, and particularly relates to a method for preparing a perovskite thin film through buried interface treatment, a perovskite solar cell and a preparation method of a perovskite / silicon laminated solar cell. The invention provides a bottom-buried interface modification method based on solvent treatment, which comprises the following steps: firstly, treating a substrate for preparing a perovskite thin film by using an organic solvent, so that the nucleation and crystallization processes of perovskite can be regulated and controlled, the interface contact and overall quality of the perovskite thin film are effectively optimized, and the crystal quality of the perovskite thin film is remarkably improved; the generation of defects is reduced, the phase separation phenomenon is inhibited, and the efficiency and the stability of the unijunction and semitransparent perovskite solar cell are obviously improved. Meanwhile, the method provided by the invention is applied to the preparation of the perovskite / silicon laminated solar cell on the textured crystal silicon substrate, effectively eliminates the gap problem of a buried interface, improves the interface contact, and finally greatly improves the conversion efficiency of the perovskite / silicon laminated solar cell.

Description

Technical Field

[0001] The invention belongs to the technical field of perovskite thin films, and specifically relates to a method for preparing a perovskite thin film by buried interface treatment, and a method for preparing a perovskite solar cell and a perovskite / silicon stacked solar cell. Background Art

[0002] Metal halide perovskite solar cells (PSCs) have emerged as strong competitors to conventional silicon photovoltaic cells, achieving power conversion efficiencies (PCEs) exceeding 26.7%. Perovskite / silicon tandem solar cells (TSCs) are considered a potential candidate to surpass the efficiency limit of single-junction solar cells. The performance of perovskite devices depends largely on the properties of the substrate (e.g., textured silicon), which can affect the nucleation density, crystal orientation, and growth rate of perovskite films. Perovskite formation is achieved through the PbI 2 -DMSO intermediate. 2 It usually has an I vacancy, so the intermediate is composed of I deficiency (organic cation)-Pb 3 I 8 Phase or I-defect PbI 2 -DMSO complexes, which can lead to non-radiative recombination due to the many defects at the phase interface. In addition, the large number of defective three-dimensional voids brought about by the evaporation of the precursor solvent dimethyl sulfoxide lead to unstable perovskite lattice structure, especially on rough surfaces. Although a rough surface generally means more nucleation sites and faster crystal growth rates, this may also lead to defect-rich perovskite films. The decline in crystal quality will lead to more ion migration pathways, which in turn accelerates crystal degradation. Therefore, under continuous illumination, phase segregation may occur in wide bandgap (WBG) absorber films, resulting in shortened device life.

[0003] The treatment of buried interface is a key method to overcome these negative effects. The buried interface, that is, the interface between the perovskite light absorption layer and the electron transport layer, is crucial to achieve efficient and stable perovskite solar cells. The buried interface treatment aims to improve the performance and stability of the device by optimizing and modifying the buried interface.

[0004] At present, the related technology uses foreign substances to pre-nucleate at the buried interface or uses additives to optimize the perovskite crystallization and morphology. However, the introduction of foreign matter (foreign substances or additives) into the perovskite film will cause impurities in the composition of the perovskite film, thereby affecting the intrinsic properties of the perovskite film. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a perovskite film by buried interface treatment, and a method for preparing a perovskite solar cell and a perovskite / silicon stacked solar cell. The method provided by the present invention can promote the uniform growth of a wide-bandgap perovskite film, effectively optimize the interface contact and overall quality of the perovskite film, reduce the generation of defects, and inhibit phase separation, so that the efficiency and stability of single-junction and semi-transparent perovskite solar cells are significantly improved.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a perovskite film by buried interface treatment, comprising the following steps:

[0008] (1) coating an organic solvent on the surface of the substrate to obtain a solvent-treated buried interface;

[0009] (2) coating a perovskite precursor solution on the solvent-treated buried interface to obtain a wet film, and annealing the wet film to obtain the perovskite thin film.

[0010] Preferably, the organic solvent comprises one or more of toluene, chlorobenzene, isopropanol, anisole, ethyl acetate and acetonitrile.

[0011] Preferably, in step (1), the coating is performed by spin coating, the rotation speed of the spin coating is 2000 to 3000 rpm, and the time is 20 to 30 s.

[0012] Preferably, the substrate is an electron transport layer; the material of the electron transport layer includes tin oxide and / or titanium oxide.

[0013] Preferably, the perovskite precursor solution comprises cesium halide, halomethylamine, haloformamidine, lead halide and an organic solvent.

[0014] Preferably, the organic solvent is a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is (3-6):1.

[0015] Preferably, the cesium halide is CsI, and the lead halide is PbI 2 and / or PbBr 2 ; The molar ratio of the cesium halide, halomethylamine and haloformamidine is (0.001-3):(0.001-5):(12-18); The molar ratio of the cesium halide and lead halide is (0.001-5):20.

[0016] Preferably, the temperature of the annealing treatment is 125-140° C., and the holding time of the annealing treatment is 15-30 min.

[0017] The present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0018] Prepare an electron transport layer on the ITO surface;

[0019] Preparing a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer;

[0020] preparing a hole transport layer on the surface of the perovskite layer;

[0021] An electrode is prepared on the surface of the hole transport layer to obtain the perovskite solar cell.

[0022] Preferably, the electrode is an Au electrode or a semi-transparent electrode; the semi-transparent electrode comprises a buffer layer, an indium zinc oxide layer and an Ag layer stacked in sequence, and the buffer layer is in contact with the hole transport layer.

[0023] The present invention provides a method for preparing a perovskite / silicon tandem solar cell, comprising the following steps:

[0024] Prepare an ITO layer on the textured crystalline silicon surface;

[0025] Preparing an electron transport layer on the surface of the ITO layer;

[0026] Preparing a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer;

[0027] preparing a hole transport layer on the surface of the perovskite layer;

[0028] An electrode is prepared on the surface of the hole transport layer to obtain the perovskite / silicon stacked solar cell.

[0029] The present invention provides a method for preparing a perovskite film by buried interface treatment, comprising the following steps: (1) coating an organic solvent on the surface of a substrate to obtain a solvent-treated buried interface; (2) coating a perovskite precursor solution on the solvent-treated buried interface to obtain a wet film, and annealing the wet film to obtain the perovskite film. The present invention provides a buried interface modification method based on solvent treatment. The present invention first uses an organic solvent to treat a substrate for preparing a perovskite film, which can regulate the nucleation and crystallization process of the perovskite, and effectively optimizes the interface contact and overall quality of the perovskite film. The present invention can achieve in-situ nucleation on the substrate at the moment when the perovskite precursor solution is coated on the solvent-treated buried interface, promote the rapid conversion of the perovskite precursor solution into the perovskite phase, and effectively inhibit the generation of the impurity phase, thereby promoting the uniform growth of a wide-bandgap perovskite film. Therefore, the buried interface treatment method provided by the present invention does not need to introduce foreign matter (foreign substances or additives) into the perovskite film, significantly improves the crystal quality of the perovskite film, reduces the generation of defects, and inhibits the phase separation phenomenon, thereby significantly improving the efficiency and stability of single-junction and semi-transparent perovskite solar cells.

[0030] At the same time, the method for preparing perovskite film by buried interface treatment provided by the present invention is applied to the preparation of perovskite / silicon stacked solar cells on a velvet crystalline silicon substrate, which effectively eliminates the gap problem of the buried interface, improves the interface contact, and ultimately greatly improves the conversion efficiency of the perovskite / silicon stacked solar cells.

[0031] Further, in the present invention, the organic solvent includes one or more of toluene, chlorobenzene, isopropanol, anisole, ethyl acetate and acetonitrile. The present invention can further improve the crystal quality of the perovskite film, reduce the generation of defects, and inhibit the phase separation phenomenon by controlling the type of organic solvent, so that the efficiency and stability of single-junction and semi-transparent perovskite solar cells are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Surface electron microscope photos of the perovskite films prepared in Example 1 and Comparative Example 1;

[0033] Figure 2 Steady-state photoluminescence spectra of the perovskite films prepared in Example 1 and Comparative Example 1 before and after aging;

[0034] Figure 3 JV diagrams of the perovskite solar cells prepared in Example 1 and Comparative Example 1;

[0035] Figure 4 Cross-sectional electron microscope photos of the perovskite films prepared in Example 2 and Comparative Example 2

[0036] Figure 5The cell JV diagrams of the perovskite / silicon tandem solar cells prepared in Example 2 and Comparative Example 2;

[0037] Figure 6 The cell JV diagram of the semi-transparent perovskite solar cells prepared in Example 3 and Comparative Example 3. DETAILED DESCRIPTION

[0038] The present invention provides a method for preparing a perovskite film by buried interface treatment, comprising the following steps:

[0039] (1) coating an organic solvent on the surface of the substrate to obtain a solvent-treated buried interface;

[0040] (2) coating a perovskite precursor solution on the solvent-treated buried interface to obtain a wet film, and annealing the wet film to obtain the perovskite thin film.

[0041] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0042] The present invention coats an organic solvent on the surface of the substrate (hereinafter referred to as the first coating) to obtain a solvent-treated buried interface. In the present invention, the organic solvent preferably includes one or more of toluene, chlorobenzene, isopropanol, anisole, ethyl acetate and acetonitrile, and toluene is most preferred. The substrate is an electron transport layer; the material of the electron transport layer preferably includes tin oxide and / or titanium oxide. The first coating is preferably spin coating, and the rotation speed of the spin coating is preferably 2000-3000rpm, and the time is preferably 20-30s. The present invention has no special requirements for the amount of toluene used, and the surface of the substrate can be covered.

[0043] After obtaining the solvent-treated buried interface, the present invention coats a perovskite precursor solution (hereinafter referred to as the second coating) on ​​the solvent-treated buried interface to obtain a wet film, and anneals the wet film (hereinafter referred to as the first annealing treatment) to obtain the perovskite film.

[0044] In the present invention, the perovskite precursor solution preferably includes cesium halide, methyl halide, methyl halide, lead halide and an organic solvent. In the present invention, the cesium halide is preferably CsI. The methyl halide is preferably methyl iodine (MAI). The methyl halide is preferably methyl iodine (FAI). The lead halide is preferably PbI 2 and / or PbBr 2In the present invention, the molar ratio of the cesium halide, methyl halide and methyl halide is preferably (0.001-3): (0.001-5): (12-18), and more preferably 1:3:16. The molar ratio of the cesium halide and the lead halide is preferably (0.001-5): 20, and more preferably 1:20. The lead halide is preferably PbI 2 and PbBr 2 When the PbI 2 and PbBr 2 The molar ratio of is preferably 5:(1-3). In the present invention, the organic solvent is preferably a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). In the present invention, the volume ratio of DMF and DMSO is preferably (3-6):1.

[0045] In the present invention, the method for preparing the perovskite precursor solution preferably comprises: dissolving cesium halide, halomethylamine, haloformamidine and lead halide in an organic solvent to obtain a perovskite precursor solution. The dissolution temperature is preferably room temperature. The dissolution time is preferably 8 hours. The dissolution is preferably carried out under stirring conditions, and the present invention has no special requirements for the specific implementation process of the stirring.

[0046] In the present invention, the second coating is preferably spin coating, and the present invention has no special requirements for the specific implementation process of the spin coating.

[0047] In the present invention, the temperature of the first annealing treatment is preferably 125-140° C., more preferably 130° C. The holding time of the first annealing treatment is preferably 15-30 min, more preferably 20 min.

[0048] The present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0049] Prepare an electron transport layer on the ITO surface;

[0050] Preparing a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer;

[0051] preparing a hole transport layer on the surface of the perovskite layer;

[0052] An electrode is prepared on the surface of the hole transport layer to obtain the perovskite solar cell.

[0053] In the present invention, the perovskite solar cell is a single-junction perovskite solar cell or a semi-transparent perovskite solar cell.

[0054] The present invention prepares an electron transport layer on the surface of ITO. The material of the electron transport layer preferably includes tin oxide and / or titanium oxide. The thickness of the electron transport layer is preferably 10 to 50 nm.

[0055] In the present invention, the method for preparing the electron transport layer preferably comprises the following steps:

[0056] The metal oxide is dissolved in ammonia water to obtain an electron transport layer precursor solution; the electron transport layer precursor solution is coated (hereinafter referred to as the third coating) on ​​the TIO surface and then a second annealing treatment is performed.

[0057] In the present invention, the metal oxide is preferably tin oxide or titanium oxide. The mass concentration of the ammonia water is preferably 25%. The present invention has no special requirements for the amount of ammonia water, as long as the metal oxide can be completely dissolved. The mass percentage of the metal oxide in the electron transport layer precursor solution is preferably 12wt%. The third coating is preferably spin coating, and the present invention has no special requirements for the specific implementation process of the spin coating. In the present invention, the temperature of the second annealing treatment is preferably 150°C. In the present invention, the holding time of the second annealing treatment is 30min.

[0058] After obtaining the electron transport layer, the present invention prepares a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer.

[0059] After obtaining the perovskite layer, the present invention prepares a hole transport layer on the surface of the perovskite layer. In the present invention, the material of the hole transport layer preferably includes 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMe TAD) or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). The thickness of the hole transport layer is preferably 80 to 120 nm.

[0060] In the present invention, the method for preparing the hole transport layer preferably comprises the following steps:

[0061] The hole transport layer material is dissolved in a polar organic solvent to obtain a hole transport layer precursor solution; the hole transport layer precursor solution is coated (hereinafter referred to as the fourth coating) on ​​the surface of the perovskite layer.

[0062] In the present invention, the hole transport layer material preferably includes Spiro-OMe TAD or PTAA. The polar organic solvent is preferably chlorobenzene. The hole transport layer precursor solution preferably also includes lithium bis(trifluoromethanesulfonyl)imide solution and 4-tert-butylpyridine. The present invention has no special requirements on the amount of the polar organic solvent, as long as it can completely dissolve the hole transport layer material. In the present invention, the fourth coating is preferably spin coating, and the present invention has no special requirements on the specific implementation process of the spin coating.

[0063] After obtaining the hole transport layer, the present invention prepares an electrode on the surface of the hole transport layer to obtain the perovskite solar cell. In the present invention, the electrode is preferably an Au electrode or a semi-transparent electrode. The thickness of the Au electrode is preferably 70nm. The semi-transparent electrode preferably includes a buffer layer, an indium zinc oxide (IZO) layer and an Ag layer stacked in sequence. The buffer layer contacts the hole transport layer, and the buffer layer is preferably MoO 3 The thickness of the buffer layer is preferably 20 nm, the thickness of the IZO layer is preferably 100 nm, and the thickness of the Ag layer is preferably 150 nm. In the present invention, the preparation method of the Au electrode is preferably vacuum evaporation. The preparation method of the buffer layer is preferably vacuum evaporation, the preparation method of the IZO layer is preferably magnetron sputtering, and the preparation method of the Ag layer is preferably vacuum evaporation.

[0064] The present invention provides a method for preparing a perovskite / silicon tandem solar cell, comprising the following steps:

[0065] Prepare an ITO layer on the textured crystalline silicon surface;

[0066] Preparing an electron transport layer on the surface of the ITO layer;

[0067] Preparing a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer;

[0068] preparing a hole transport layer on the surface of the perovskite layer;

[0069] An electrode is prepared on the surface of the hole transport layer to obtain the perovskite / silicon stacked solar cell.

[0070] The present invention prepares an ITO layer on the surface of textured crystalline silicon. The present invention has no special requirements on the preparation method of the ITO layer.

[0071] After obtaining the ITO layer, the present invention prepares an electron transport layer on the surface of the ITO layer. In the present invention, the preparation method of the electron transport layer in the perovskite / silicon tandem solar cell is the same as the preparation method of the electron transport layer in the above-mentioned perovskite solar cell, which will not be repeated here.

[0072] After obtaining the electron transport layer, the present invention prepares a perovskite film on the surface of the electron transport layer according to the method described in the above technical solution to obtain a perovskite layer.

[0073] After obtaining the perovskite layer, the present invention prepares a hole transport layer on the surface of the perovskite layer. In the present invention, the preparation method of the hole transport layer in the perovskite / silicon stacked solar cell is the same as the preparation method of the hole transport layer in the above-mentioned perovskite solar cell, which will not be repeated here.

[0074] After obtaining the hole transport layer, the present invention prepares an electrode on the surface of the hole transport layer to obtain the perovskite / silicon tandem solar cell. In the present invention, the electrode of the perovskite / silicon tandem solar cell is preferably a semi-transparent electrode. The semi-transparent electrode preferably includes a buffer layer, an indium zinc oxide (IZO) layer and an Ag layer stacked in sequence. The buffer layer contacts the hole transport layer, and the buffer layer is preferably MoO 3 The thickness of the buffer layer is preferably 20 nm, the thickness of the IZO layer is preferably 100 nm, and the thickness of the Ag layer is preferably 150 nm. In the present invention, the preparation method of the buffer layer is preferably vacuum evaporation, the preparation method of the IZO layer is preferably magnetron sputtering, and the preparation method of the Ag layer is preferably vacuum evaporation.

[0075] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0076] Example 1

[0077] (1) SnO 2 Dissolved in 25% ammonia water to obtain an electron transport layer precursor solution (SnO 2 , 12wt%); the electron transport layer precursor solution was spin-coated on the surface of the ITO substrate and annealed at 150°C for 30min to obtain SnO 2 Electron transport layer, thickness 40nm.

[0078] (2) Spin-coat the toluene solvent onto the surface of the electron transport layer at a rotation speed of 3000 rpm for 30 seconds to obtain a solvent-treated buried interface.

[0079] (3) 0.06 mol of CsI, 0.18 mol of MAI, 0.9 mol of FAI, and 0.75 mol of PbI 2 and 0.45 mol of PbBr 2Dissolve in a mixed organic solvent of DMF and DMSO in sequence, wherein the volume ratio of DMF to DMSO is 4:1, stir and mix at room temperature for 8 hours to obtain a perovskite precursor solution; spin-coat the perovskite precursor solution on the buried interface treated with the solvent obtained in step (2), anneal at 130°C for 20 minutes to obtain a halide perovskite film (i.e., a toluene-treated halide perovskite film), and obtain a perovskite layer. The surface electron microscope photograph of the toluene-treated halide perovskite film prepared in this embodiment is shown in FIG. Figure 1 As shown in Figure b.

[0080] (4) Dissolve 0.0723 g of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMe TAD) in 1 mL of chlorobenzene, then add 35 μL of lithium bis(trifluoromethanesulfonyl)imide and 30 μL of 4-tert-butylpyridine in sequence and stir evenly to obtain a hole transport layer precursor solution; spin-coat the hole transport layer precursor solution on the surface of the perovskite layer to obtain a hole transport layer with a thickness of 80 to 120 nm.

[0081] (5) A vacuum evaporation method is used to evaporate 70 nm of gold as an electrode on the surface of the hole transport layer to obtain a perovskite solar cell (i.e., a toluene-treated perovskite solar cell).

[0082] Comparative Example 1

[0083] (1) SnO 2 Dissolved in 25% ammonia water to obtain an electron transport layer precursor solution (SnO 2 , 12wt%); the electron transport layer precursor solution was spin-coated on the surface of the ITO substrate and annealed at 150°C for 30min to obtain SnO 2 Electron transport layer, thickness 40nm.

[0084] (2) 0.06 mol of CsI, 0.18 mol of MAI, 0.9 mol of FAI, and 0.75 mol of PbI 2 and 0.45 mol of PbBr 2 The mixture was dissolved in a mixed organic solvent of DMF and DMSO in a volume ratio of 4:1, and stirred for 8 hours at room temperature to obtain a perovskite precursor solution. The perovskite precursor solution was spin-coated on SnO 2 The electron transport layer was annealed at 130°C for 20 minutes to obtain an untreated halide perovskite film. The surface electron microscope photo of the untreated halide perovskite film prepared in this comparative example is shown in FIG. Figure 1 As shown in Figure a.

[0085] (3) Dissolve 0.0723 g of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMe TAD) in 1 mL of chlorobenzene, then add 35 μL of lithium bis(trifluoromethanesulfonyl)imide and 30 μL of 4-tert-butylpyridine in sequence and stir evenly to obtain a hole transport layer precursor solution; spin-coat the hole transport layer precursor solution on the surface of the untreated perovskite layer in step (2) to obtain a hole transport layer with a thickness of 80 to 120 nm.

[0086] (4) A vacuum evaporation method is used to evaporate a gold single substance with a thickness of 70 nm on the surface of the hole transport layer as an electrode to obtain a perovskite solar cell (i.e., an untreated perovskite solar cell).

[0087] Depend on Figure 1 The results show that the grains of the halide perovskite film treated with toluene prepared in Example 1 become larger, the particle size of the crystals is more uniform, and the uniform defects are reduced, which is different from SnO 2 The contact of the electron transport layer is closer, which suppresses the phase separation phenomenon.

[0088] Test Example 1

[0089] The toluene-treated halide perovskite film prepared in Example 1 and the untreated halide perovskite film prepared in Comparative Example 1 were subjected to a 100 mW / cm 2 The intensity of the film was continuously irradiated with 365nm ultraviolet light for 5 minutes for aging treatment, and then the steady-state photoluminescence (PL) of the two perovskite films before and after aging was measured. The results are as follows Figure 2 As shown, the steady-state photoluminescence spectra of the untreated halide perovskite film prepared in Comparative Example 1 before and after aging are shown in Figure 2 As shown in a in the figure, the steady-state photoluminescence spectra of the toluene-treated halide perovskite film prepared in Example 1 before and after aging are shown in Figure 2 As shown in b.

[0090] Depend on Figure 2 It can be seen that the main peak of the untreated halide perovskite film prepared in Comparative Example 1 shows a red shift after 5 minutes of illumination, indicating the formation of a low-bandgap iodine-rich domain. In contrast, the toluene-treated halide perovskite film prepared in Example 1 shows no peak shift after 5 minutes of illumination, and no lower energy peak is formed.

[0091] Test Example 2

[0092] The cell JV diagrams of the toluene-treated perovskite solar cell prepared in Example 1 and the untreated perovskite solar cell prepared in Comparative Example 1 were tested. The results are as follows: Figure 3 And as shown in Table 1.

[0093] Table 1 Performance test results of perovskite solar cells prepared in Example 1 and Comparative Example 1

[0094] NO. <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE(%) Comparative Example 1 Product 1.21 20.04 71.82 17.47 Example 1 Product 1.25 21.61 75.62 20.41

[0095] Depend on Figure 3 As shown in Table 1, the efficiency of the toluene-treated perovskite solar cell prepared in Example 1 is significantly improved.

[0096] Example 2

[0097] (1) SnO 2 Dissolved in 25% ammonia water to obtain an electron transport layer precursor solution (SnO 2 , 12wt%); an ITO layer was prepared on the surface of a suede crystalline silicon substrate, and an electron transport layer precursor solution was spin-coated on the surface of the ITO layer, and annealed at 150°C for 30min to obtain SnO 2 Electron transport layer, thickness 40nm.

[0098] (2) Spin-coat the toluene solvent on the surface of the electron transport layer at a rotation speed of 3000 rpm for 30 seconds to obtain a solvent-treated buried interface.

[0099] (3) 0.06 mol of CsI, 0.18 mol of MAI, 0.9 mol of FAI, and 0.75 mol of PbI 2 and 0.45 mol of PbBr 2 Dissolve in a mixed organic solvent of DMF and DMSO in sequence, wherein the volume ratio of DMF to DMSO is 4:1, stir and mix at room temperature for 8 hours to obtain a perovskite precursor solution; spin-coat the perovskite precursor solution on the buried interface treated with the solvent obtained in step (2), anneal at 130°C for 20 minutes to obtain a halide perovskite film (i.e., a toluene-treated halide perovskite film), and obtain a perovskite layer. The cross-sectional electron microscope photograph of the toluene-treated halide perovskite film prepared in this embodiment is shown in FIG. Figure 4 As shown in Figure b.

[0100] (4) Dissolve 0.0723 g of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMe TAD) in 1 mL of chlorobenzene, then add 35 μL of lithium bis(trifluoromethanesulfonyl)imide and 30 μL of 4-tert-butylpyridine in sequence and stir evenly to obtain a hole transport layer precursor solution; spin-coat the hole transport layer precursor solution on the surface of the perovskite layer to obtain a hole transport layer with a thickness of 80 to 120 nm.

[0101] (5) Using vacuum evaporation equipment, 20 nm MoO was evaporated on the hole transport layer. 3As a buffer layer, 100nm IZO is further sputtered using a magnetron sputtering device, and finally a 150nm Ag layer is evaporated using a vacuum evaporation device to obtain a semi-transparent electrode to obtain a perovskite / silicon stacked solar cell.

[0102] Comparative Example 2

[0103] (1) SnO 2 Dissolved in 25% ammonia water to obtain an electron transport layer precursor solution (SnO 2 , 12wt%); an ITO layer was prepared on the surface of a suede crystalline silicon substrate, and an electron transport layer precursor solution was spin-coated on the surface of the ITO layer, and annealed at 150°C for 30min to obtain SnO 2 Electron transport layer, thickness 40nm.

[0104] (2) 0.06 mol of CsI, 0.18 mol of MAI, 0.9 mol of FAI, and 0.75 mol of PbI 2 and 0.45 mol of PbBr 2 Dissolve in a mixed organic solvent of DMF and DMSO in turn, wherein the volume ratio of DMF to DMSO is 4:1, and stir and mix at room temperature for 8 hours to obtain a perovskite precursor solution; spin-coat the perovskite precursor solution on the SnO 2 The electron transport layer was annealed at 130°C for 20 minutes to obtain an untreated halide perovskite film. The side electron microscope photo of the untreated halide perovskite film prepared in this comparative example is shown in FIG. Figure 4 As shown in Figure a.

[0105] (3) Dissolve 0.0723 g of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMe TAD) in 1 mL of chlorobenzene, then add 35 μL of lithium bis(trifluoromethanesulfonyl)imide and 30 μL of 4-tert-butylpyridine in sequence and stir evenly to obtain a hole transport layer precursor solution; spin-coat the hole transport layer precursor solution on the surface of the perovskite layer treated in step (2) to obtain a hole transport layer with a thickness of 80 to 120 nm.

[0106] (4) Using vacuum evaporation equipment, 20 nm MoO was evaporated on the hole transport layer. 3 As a buffer layer, 100nm IZO is further sputtered using a magnetron sputtering device, and finally a 150nm Ag layer is evaporated using a vacuum evaporation device to obtain a semi-transparent electrode to obtain a perovskite / silicon stacked solar cell.

[0107] Depend on Figure 4 The results show that the buried interface voids of the perovskite / silicon tandem solar cell prepared in Example 2 are significantly reduced.

[0108] Test Example 3

[0109] The cell JV diagrams of the toluene-treated perovskite / silicon tandem solar cell prepared in Example 2 and the untreated perovskite / silicon tandem solar cell prepared in Comparative Example 2 were tested. The results are as follows: Figure 5 And as shown in Table 2.

[0110] Table 2 Performance test results of perovskite / silicon tandem solar cells prepared in Example 2 and Comparative Example 2

[0111] NO. <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE(%) Comparative Example 2 Product 1.77 16.78 73.57 21.85 Example 2 Product 1.86 18.38 76.10 26.01

[0112] Depend on Figure 5 As shown in Table 2, the efficiency of the perovskite / silicon tandem solar cell prepared in Example 2 is significantly improved.

[0113] Example 3

[0114] The preparation method is basically the same as that of Example 1, except that step (5) is replaced by: (5) using a vacuum evaporation device to evaporate 20 nm MoO on the hole transport layer. 3 As a buffer layer, 100nm IZO was further sputtered using a magnetron sputtering device, and finally a 150nm Ag layer was evaporated using a vacuum evaporation device to obtain a semi-transparent electrode, thereby obtaining a toluene-treated semi-transparent perovskite solar cell.

[0115] Comparative Example 3

[0116] The preparation method is basically the same as that of Comparative Example 1, except that step (4) is replaced by: (4) using a vacuum evaporation device to evaporate 20 nm MoO on the hole transport layer. 3 As a buffer layer, 100nm IZO was further sputtered using a magnetron sputtering device, and finally a 150nm Ag layer was evaporated using a vacuum evaporation device to obtain a semi-transparent electrode, thereby obtaining an untreated semi-transparent perovskite solar cell.

[0117] Test Example 4

[0118] The cell JV diagrams of the toluene-treated semi-transparent perovskite solar cell prepared in Example 3 and the untreated semi-transparent perovskite solar cell prepared in Comparative Example 3 were tested. The results are as follows: Figure 6 And as shown in Table 3.

[0119] Table 3 Performance test results of semi-transparent perovskite solar cells prepared in Example 3 and Comparative Example 3

[0120] Solvents <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE(%) Comparative Example 3 Product 1.15 19.79 71.92 16.33 Example 3 Product 1.21 21.05 76.49 19.48

[0121] Depend on Figure 6As shown in Table 3, the efficiency of the toluene-treated semi-transparent perovskite solar cell prepared in Example 3 is significantly improved after being treated with toluene.

[0122] Example 4

[0123] The preparation method is basically the same as that of Example 1, except that the toluene used in step (2) is replaced by chlorobenzene.

[0124] Example 5

[0125] The preparation method is basically the same as that of Example 1, except that the toluene used in step (2) is replaced by isopropanol.

[0126] Example 6

[0127] The preparation method is basically the same as that of Example 1, except that the toluene used in step (2) is replaced by anisole.

[0128] Example 7

[0129] The preparation method is basically the same as that of Example 1, except that the toluene used in step (2) is replaced by ethyl acetate.

[0130] Example 8

[0131] The preparation method is basically the same as that of Example 1, except that the toluene used in step (2) is replaced by acetonitrile.

[0132] Test Example 7

[0133] The performance test results of the perovskite solar cells prepared in Examples 4 to 8 are shown in Table 4.

[0134] Table 4 Performance test results of titanium ore solar cells prepared in Examples 4 to 8

[0135] NO. <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE(%) Example 4 Product 1.21 20.69 72.23 18.11 Example 5 Product 1.24 20.23 76.46 19.15 Example 6 Product 1.22 20.87 75.83 19.27 Example 7 Product 1.20 20.71 74.29 18.30 Example 8 Product 1.23 20.24 76.41 19.98

[0136] From Table 4 and Figure 3 Compared with Table 1, it can be seen that Examples 4 to 8 respectively use chlorobenzene, isopropanol, anisole, ethyl acetate and acetonitrile for bottom buried interface treatment, which can achieve basically the same effect as the toluene bottom buried interface treatment.

[0137] From the above examples, it can be seen that the present invention uses toluene, a common laboratory solvent, to treat the buried interface, in-situ pre-nucleation, and prepares a perovskite film with a large grain size. In particular, on a rough substrate (such as suede silicon), the buried interface voids can be reduced, and a high-quality perovskite film can be prepared on the rough substrate, thereby preparing high-performance perovskite and stacked devices.

[0138] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite film by buried interface treatment, characterized in that: The following steps are involved: (1) coating an organic solvent on the surface of the substrate to obtain a solvent-treated buried interface; (2) coating a perovskite precursor solution on the solvent-treated buried interface to obtain a wet film, and annealing the wet film to obtain the perovskite thin film.

2. The method according to claim 1, characterized in that The organic solvent includes one or more of toluene, chlorobenzene, isopropanol, anisole, ethyl acetate and acetonitrile.

3. The method according to claim 1, characterized in that In step (1): the coating is spin coating, the rotation speed of the spin coating is 2000-3000 rpm, and the time is 20-30s.

4. The method according to claim 1, characterized in that: The substrate is an electron transport layer; the material of the electron transport layer includes tin oxide and / or titanium oxide.

5. The method according to claim 1, characterized in that The perovskite precursor solution includes cesium halide, halomethylamine, haloformamidine, lead halide and an organic solvent; The organic solvent is a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is (3-6):

1.

6. The method according to claim 5, characterized in that The cesium halide is CsI, and the lead halide is PbI2 and / or PbBr2; The molar ratio of the cesium halide, methyl halide and methyl halide is (0.001-3):(0.001-5):(12-18); the molar ratio of the cesium halide and lead halide is (0.001-5):

20.

7. The method according to any one of claims 1 to 6, characterized in that: The temperature of the annealing treatment is 125-140° C., and the holding time of the annealing treatment is 15-30 minutes.

8. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: Prepare an electron transport layer on the ITO surface; Preparing a perovskite film on the surface of the electron transport layer according to the method according to any one of claims 1 to 7 to obtain a perovskite layer; preparing a hole transport layer on the surface of the perovskite layer; An electrode is prepared on the surface of the hole transport layer to obtain the perovskite solar cell.

9. The preparation method according to claim 8, characterized in that: The electrode is an Au electrode or a semi-transparent electrode; The semi-transparent electrode includes a buffer layer, an indium zinc oxide layer and an Ag layer which are stacked in sequence, and the buffer layer is in contact with the hole transport layer.

10. A method for preparing a perovskite / silicon tandem solar cell, characterized in that: The following steps are involved: Prepare an ITO layer on the textured crystalline silicon surface; Preparing an electron transport layer on the surface of the ITO layer; Preparing a perovskite film on the surface of the electron transport layer according to the method according to any one of claims 1 to 7 to obtain a perovskite layer; preparing a hole transport layer on the surface of the perovskite layer; An electrode is prepared on the surface of the hole transport layer to obtain the perovskite / silicon stacked solar cell.

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