Perovskite precursor solution, preparation method thereof and perovskite solar cell

Abstract

The invention belongs to the technical field of solar cells, and particularly relates to a perovskite precursor solution, a preparation method thereof and a perovskite solar cell. The perovskite precursor solution provided by the invention contains the 2-hydrazino-2-imidazoline hydrobromide, and the perovskite precursor solution contains the 2-hydrazino-2-imidazoline hydrobromide. An imidazoline group in the 2-hydrazino-2-imidazoline hydrobromide in the perovskite precursor solution can be embedded into a perovskite lead iodine octahedron, thin film crystal lattices are stabilized, and thin film defects are passivated; the hydrazine group can inhibit the process that iodide ions in the perovskite precursor solution are oxidized into iodine simple substances, and the stability of the solar cell is improved.

Description

Technical Field

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

[0002] As the global demand for clean energy continues to grow, the development and utilization of solar energy as a clean and renewable energy source has received widespread attention. Perovskite solar cells have become a research hotspot in the current photovoltaic field due to their significant advantages such as high photoelectric conversion efficiency, solution processing and low cost.

[0003] In perovskite solar cells, there are a large number of defect states on the surface and grain boundaries of perovskite materials. These defects will capture carriers, leading to serious non-radiative recombination losses, greatly reducing the photoelectric conversion efficiency and stability of the cell. Therefore, passivation technology plays a key role in improving the performance of perovskite solar cells.

[0004] At present, a variety of technical means have been developed for the passivation of perovskite solar cells. For example, organic molecule passivation technology uses specific organic molecules to cover the surface defects of perovskite materials. For example, terpyridine molecules can be stacked in an orderly manner on the surface of perovskite at high concentrations, causing little damage to the lattice, and are conducive to the extraction and transmission of interfacial charges, which can improve the photoelectric conversion efficiency of the device. However, conventional organic passivators have concentration problems. Low-concentration passivators designed for freshly prepared devices are difficult to continuously passivate new defects generated during battery operation, and increasing the concentration will have a negative impact on device performance.

[0005] The binary synergistic passivation strategy forms a high-quality passivation layer by mixing two organic halide salts (such as 4-tBBAI and phenylpropylammonium iodide) and spin-coating them on the perovskite surface, which can reduce the surface defect state density, enhance crystallinity, optimize the energy band arrangement, etc. However, this technology increases the complexity and cost of the preparation process, which is not conducive to large-scale production.

[0006] In summary, although the existing perovskite solar cell passivation technology has improved the cell performance to a certain extent, it still has many shortcomings. Therefore, it is urgent to develop a new passivation technology to overcome the defects of related technologies, further improve the photoelectric conversion efficiency and stability of perovskite solar cells, and reduce production costs at the same time to promote the industrialization of perovskite solar cells. Summary of the invention

[0007] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, an embodiment of the present invention provides a perovskite precursor solution, wherein the 2-hydrazine-2-imidazoline hydrobromide contained in the perovskite precursor solution can not only passivate the defects of the perovskite film, but also improve the stability of the solar cell.

[0008] The perovskite precursor solution of the embodiment of the present invention contains 2-hydrazine-2-imidazoline hydrobromide.

[0009] The advantages and technical effects brought by the perovskite precursor solution of the embodiment of the present invention are as follows: 1. In the embodiment of the present invention, the imidazoline group in 2-hydrazine-2-imidazoline hydrobromide can be embedded in the perovskite lead-iodine octahedron to form a low-dimensional perovskite, thereby increasing the moisture resistance of the perovskite film, stabilizing the perovskite film lattice, and passivating the defects of the perovskite film; 2. In the embodiment of the present invention, the hydrazine group in 2-hydrazine-2-imidazoline hydrobromide can inhibit the oxidation process of iodine ions in the perovskite precursor solution to elemental iodine, thereby improving the stability of the solar cell.

[0010] In some embodiments, the content of 2-hydrazino-2-imidazoline hydrobromide in the perovskite precursor solution is 0.01-2 mg / mL.

[0011] The embodiment of the present invention further provides a method for preparing a perovskite precursor solution, comprising dissolving a perovskite precursor material in an organic solvent and then adding 2-hydrazine-2-imidazoline hydrobromide and mixing the mixture evenly.

[0012] In some embodiments, the perovskite precursor material includes ABX 3 At least one of the following, wherein A is a methylamine group, a formamidine group or cesium, B is Pb, Sn or Ge, and X is I, Br or Cl;

[0013] And / or, the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0014] The present invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0015] (1) pre-treating the ITO glass and depositing a first carrier transport layer on the ITO surface;

[0016] (2) applying the above-mentioned perovskite precursor solution or the perovskite precursor solution prepared by the above-mentioned preparation method on the surface of the first carrier transport layer, and forming a perovskite absorption layer after annealing;

[0017] (3) depositing a second carrier transport layer on the surface of the perovskite absorption layer;

[0018] (4) Depositing a back electrode layer on the surface of the second carrier transport layer.

[0019] In some embodiments, in step (1), the pretreatment includes: ultrasonically treating the ITO glass in acetone and ethanol for 5 to 20 minutes respectively, drying with nitrogen, and then treating with plasma for 10 to 30 minutes.

[0020] In some embodiments, in step (2), the coating method is spin coating, scraper coating or spray coating.

[0021] In some embodiments, in step (2), the annealing temperature is 100-150° C., and the annealing time is 10-30 min.

[0022] In some embodiments, in step (1), the raw material of the first carrier transport layer includes at least one of nickel oxide, cuprous iodide or cuprous thiocyanate;

[0023] And / or, in the step (3), the raw material of the second carrier transport layer includes C60, BCP, TiO 2 or SnO 2 At least one of;

[0024] And / or, in the step (4), the raw material of the back electrode layer includes at least one of Cu and Al.

[0025] The embodiment of the present invention further provides a perovskite solar cell, which is prepared by the above-mentioned preparation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a current-voltage curve diagram of the perovskite solar cell of Example 1, Example 1 after aging, Comparative Example 1, and Comparative Example 1 after aging. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0028] The perovskite precursor solution of the embodiment of the present invention contains 2-hydrazine-2-imidazoline hydrobromide.

[0029] The molecular formula of the 2-hydrazine-2-imidazoline hydrobromide is shown in Formula I:

[0030]

[0031] In the perovskite precursor solution of the embodiment of the present invention, the imidazoline group in 2-hydrazine-2-imidazoline hydrobromide can be embedded in the perovskite lead iodine octahedron to form a low-dimensional perovskite, thereby increasing the moisture resistance of the perovskite film, stabilizing the perovskite film lattice, and passivating the defects of the perovskite film; in the embodiment of the present invention, the hydrazine group in 2-hydrazine-2-imidazoline hydrobromide can inhibit the oxidation process of iodine ions in the perovskite precursor solution to elemental iodine, thereby improving the stability of the solar cell.

[0032] In some embodiments, preferably, the content of 2-hydrazine-2-imidazoline hydrobromide in the perovskite precursor solution is 0.01 to 2 mg / mL, for example, 0.01 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.6 mg / mL, 0.8 mg / mL, 1.0 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL or 2.0 mg / mL, etc.

[0033] In the embodiment of the present invention, the content of 2-hydrazino-2-imidazoline hydrobromide is preferably selected, which can ensure excellent passivation and antioxidant effects without affecting the carrier transport performance of the battery; if the addition amount of 2-hydrazino-2-imidazoline hydrobromide is too high, a large amount of low-dimensional structure perovskite will be formed, affecting the carrier transport performance of the battery; if the addition amount of 2-hydrazino-2-imidazoline hydrobromide is too low, the passivation and stability are not significantly improved.

[0034] The embodiment of the present invention further provides a method for preparing a perovskite precursor solution, comprising dissolving a perovskite precursor material in an organic solvent and then adding 2-hydrazine-2-imidazoline hydrobromide and mixing the mixture evenly.

[0035] In some embodiments, preferably, the perovskite precursor material includes ABX 3 At least one of the following, wherein A is a methylamine group, a formamidine group or cesium, B is Pb, Sn or Ge, and X is I, Br or Cl;

[0036] And / or, the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0037] The present invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0038] (1) pre-treating the ITO glass and depositing a first carrier transport layer on the ITO surface;

[0039] (2) applying the above-mentioned perovskite precursor solution or the perovskite precursor solution prepared by the above-mentioned preparation method on the surface of the first carrier transport layer, and forming a perovskite absorption layer after annealing;

[0040] (3) depositing a second carrier transport layer on the surface of the perovskite absorption layer;

[0041] (4) Depositing a back electrode layer on the surface of the second carrier transport layer.

[0042] In some embodiments, preferably, in the step (1), the pretreatment comprises: ultrasonically treating the ITO glass in acetone and ethanol for 5 to 20 minutes respectively, drying with nitrogen, and then treating with plasma for 10 to 30 minutes.

[0043] In some embodiments, preferably, in the step (2), the coating is performed by spin coating, scraper coating or spray coating.

[0044] In some embodiments, preferably, in the step (2), the temperature of the annealing treatment is 100-150°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, and the time of the annealing treatment is 10-30min, for example, 10min, 12min, 14min, 16min, 18min, 20min, 22min, 24min, 26min, 28min or 30min, etc.

[0045] In the embodiment of the present invention, the annealing conditions are optimized, which is conducive to forming a perfectly crystallized perovskite layer and improving the comprehensive performance of the battery; if the annealing temperature is too high or the treatment time is too long, it is easy to cause the decomposition of organic components in the perovskite film, which has an adverse effect on the performance of the perovskite solar cell; if the annealing temperature is too low or the treatment time is too short, it is not conducive to the crystallization of the perovskite film, causing the photoelectric performance of the battery to deteriorate.

[0046] In some embodiments, preferably, in step (1), the raw material of the first carrier transport layer includes at least one of nickel oxide, cuprous iodide or cuprous thiocyanate;

[0047] And / or, in the step (3), the raw materials of the second carrier transport layer include C60, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TiO 2 or SnO 2 At least one of;

[0048] And / or, in the step (4), the raw material of the back electrode layer includes at least one of Cu and Al.

[0049] The embodiment of the present invention further provides a perovskite solar cell, which is prepared by the above-mentioned preparation method.

[0050] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and drawings.

[0051] Example 1

[0052] (1) ITO glass was purchased, and the ITO glass was ultrasonically treated in acetone and ethanol for 10 min each, dried with nitrogen, and then treated with plasma for 20 min, and then a 20 nm thick nickel oxide was sprayed on one side of the ITO layer as the first carrier transport layer;

[0053] (2) dissolving lead iodide, lead bromide, formamidinium iodide and cesium iodide in a molar ratio of 0.85:0.15:0.78:0.22 in a mixed solution of DMF and DMSO in a volume ratio of 4:1, and then adding 2-hydrazino-2-imidazoline hydrobromide to make the content of 2-hydrazino-2-imidazoline hydrobromide in the titanium ore precursor solution 0.5 mg / mL;

[0054] (3) spin coating the perovskite precursor solution on the surface of the first carrier transport layer to form a perovskite wet film, followed by annealing at 100° C. for 30 min to obtain a perovskite layer with a thickness of 100 μm;

[0055] (5) evaporating C60 / BCP to form a 20 nm thick C60 layer and a 3 nm thick BCP layer on the perovskite layer as the second carrier transport layer;

[0056] (6) Cu was evaporated on the surface of the second carrier transport layer to form a Cu electrode with a thickness of 100 nm.

[0057] Example 2

[0058] The preparation method of this embodiment is the same as that of Example 1, except that in step (2), the content of 2-hydrazino-2-imidazoline hydrobromide in the titanium ore precursor solution is 2 mg / mL.

[0059] Example 3

[0060] The preparation method of this embodiment is the same as that of embodiment 1, except that in step (3), the annealing temperature is 150° C. and the annealing time is 20 min.

[0061] Comparative Example 1

[0062] The preparation method of this comparative example is the same as that of Example 1, except that in step (2), only the perovskite precursor material is dissolved in an organic solvent to prepare the perovskite precursor solution.

[0063] Comparative Example 2

[0064] The preparation method of this comparative example is the same as that of Example 1, except that methylamine hydrobromide is used in step (2) instead of 2-hydrazino-2-imidazoline hydrobromide, so that the content of methylamine hydrobromide in the titanium ore precursor solution is 0.5 mg / mL.

[0065] The performance of the perovskite solar cells prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was tested. The testing method was: under the standard light of one sun, the current-voltage curve of the battery was tested to obtain the photoelectric conversion efficiency of the battery. The results are shown in Table 1.

[0066] The perovskite solar cells prepared in Example 1 and Comparative Example 1 were aged for 1000 h in an environment of 25°C and 85% humidity, and the aged perovskite solar cells were subjected to JV tests. The results are shown in Table 1. The JV curves of the perovskite solar cells in Example 1, after aging of Example 1, Comparative Example 1, and after aging of Comparative Example 1 are shown in Table 1. Figure 1 shown.

[0067] Table 1

[0068]

[0069]

[0070] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0071] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A perovskite precursor solution, characterized in that: The perovskite precursor solution contains 2-hydrazino-2-imidazoline hydrobromide.

2. The perovskite precursor solution according to claim 1, characterized in that The content of 2-hydrazino-2-imidazoline hydrobromide in the perovskite precursor solution is 0.01-2 mg / mL.

3. The method for preparing a perovskite precursor solution according to claim 1 or 2, characterized in that: The method comprises dissolving the perovskite precursor material in an organic solvent and then adding 2-hydrazine-2-imidazoline hydrobromide and mixing the mixture evenly.

4. The method for preparing a perovskite precursor solution according to claim 3, characterized in that: The perovskite precursor material includes at least one of ABX3, wherein A is a methylamine group, a formamidine group or cesium, B is Pb, Sn or Ge, and X is I, Br or Cl; And / or, the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide or N-methylpyrrolidone.

5. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: (1) pre-treating the ITO glass and depositing a first carrier transport layer on the ITO surface; (2) coating the perovskite precursor solution according to claim 1 or 2 or the perovskite precursor solution prepared by the preparation method according to claim 3 or 4 on the surface of the first carrier transport layer, and forming a perovskite absorption layer after annealing; (3) depositing a second carrier transport layer on the surface of the perovskite absorption layer; (4) Depositing a back electrode layer on the surface of the second carrier transport layer.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step (1), the pretreatment comprises: subjecting the ITO glass to ultrasonic treatment in acetone and ethanol for 5 to 20 minutes respectively, drying with nitrogen, and then subjecting the glass to plasma treatment for 10 to 30 minutes.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step (2), the coating method is spin coating, scraper coating or spray coating.

8. The method for preparing a perovskite solar cell according to claim 5 or 7, characterized in that: In the step (2), the temperature of the annealing treatment is 100 to 150° C., and the time of the annealing treatment is 10 to 30 minutes.

9. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step (1), the raw material of the first carrier transport layer includes at least one of nickel oxide, cuprous iodide or cuprous thiocyanate; And / or, in step (3), the raw material of the second carrier transport layer includes at least one of C60, BCP, TiO2 or SnO2; And / or, in the step (4), the raw material of the back electrode layer includes at least one of Cu and Al.

10. A perovskite solar cell, characterized in that: The preparation method is described in any one of claims 5 to 9.

Images