Cuprous iodide and preparation method thereof and inverse perovskite solar cell

Abstract

The present invention discloses cuprous iodide, a preparation method thereof and a trans-perovskite solar cell. The preparation method comprises mixing an organic cuprous salt, an organic iodine amine compound and a solvent and reacting to obtain cuprous iodide. The present invention provides a new method for preparing cuprous iodide: cuprous iodide is prepared using an organic cuprous salt and an organic iodine amine compound. The results show that the cuprous iodide prepared by this method, as a hole transport layer material for a trans-perovskite solar cell, reduces the surface roughness of the hole transport layer and makes the nucleation sites on the surface of the hole transport layer more dispersed, which is beneficial to the film crystallization of the perovskite and improves the film quality. Compared with cuprous iodide prepared by traditional methods, the hole transport layer constructed by the cuprous iodide prepared by the present invention has a very suitable energy level match with the perovskite, which is more conducive to the extraction and transmission of carriers, etc., thereby improving the photoelectric conversion efficiency of the overall perovskite solar cell.

Description

Technical Field

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

[0002] Against the backdrop of increasing energy demand, the development and utilization of solar energy has always been a hot topic of research. Therefore, solar cells that convert solar energy into electrical energy have been widely studied and developed rapidly. Not only are the types of solar cells becoming more and more abundant, but the conversion efficiency has also steadily increased. In just over a decade, the conversion efficiency of new perovskite solar cells has been comparable to that of silicon-based solar cells, and its efficiency has rapidly developed from 3.8% in 2009 to 26.1% certified in 2023. Among them, perovskite solar cells with an inverted device structure have attracted the attention of scientific researchers due to their advantages such as simple preparation process, flexibility and large-area preparation, and have great development potential in the process of commercializing perovskite solar cells.

[0003] In trans perovskite solar cells, the hole transport layer becomes an important component of the trans device due to its excellent hole extraction ability, and the perovskite light absorption layer is directly deposited on the hole transport layer, so the film quality and hole extraction of the perovskite are closely related to the hole transport layer and directly affect the final device performance. Among them, the common organic hole transport layers in trans devices include PEDOT:PSS, PTAA, 2Pacz, etc., but the complex preparation process and high price of these organic hole transport materials hinder their large-scale production, and due to their organic characteristics, they also pose a huge challenge to the stability of perovskite solar cells. These characteristics greatly limit the commercialization process of perovskite solar cells. The preparation method of traditional inorganic hole materials such as CuI is as follows: iodine salt is used as a precipitant by precipitation method, added to a salt solution containing metal copper ions for chemical reaction, and then dissolved in ammonia reagent, and the CuI hole transport layer is generated on conductive glass by spin coating. This method is low-cost, simple to operate, and has good solid stability. However, due to its inherent properties and energy level mismatch with perovskite, the CuI hole transport layer increases its interface non-radiative recombination and has poor hole extraction ability, which also leads to poor device performance and is not conducive to the further development of perovskite solar cells. Therefore, how to improve the CuI hole transport layer through preparation methods and subsequent optimization and optimize its shortcomings while maintaining its advantages to improve the performance of perovskite solar cells is still an urgent problem and challenge to be solved. Summary of the invention

[0004] In view of the problems existing in the prior art, especially for the inverse perovskite solar cell using CuI as the hole transport layer, the present invention provides a novel method for synthesizing CuI and using it as the hole transport layer to solve the above problems, and provides a method for preparing an efficient and stable inverse perovskite solar cell, which has the characteristics of good hole transport layer film quality, uniform and dense perovskite film, high power conversion efficiency and excellent thermal stability.

[0005] In order to achieve the above object, the present invention provides a method for preparing cuprous iodide, characterized in that it comprises:

[0006] The organic cuprous salt, the organic iodine amine compound and the solvent are mixed and reacted to obtain cuprous iodide.

[0007] Furthermore, the organic cuprous salt includes at least one of cuprous acetate, cuprous diphenyl phosphate, and cuprous trifluoromethanesulfonate toluene complex.

[0008] Furthermore, the organic iodine amine compound includes at least one of iodine methylamine, iodine formamidine, and phenethylamine hydroiodide.

[0009] Furthermore, the solvent includes isopropanol.

[0010] Furthermore, the molar concentrations of the organic cuprous salt and the organic iodine amine compound are 5-20 mol / L and 0.5-2 mol / L, respectively.

[0011] The present invention also provides cuprous iodide, which is obtained by the above-mentioned preparation method.

[0012] The present invention also provides the application of the above cuprous iodide in an inverse perovskite solar cell.

[0013] The present invention also provides an inverted perovskite solar cell, comprising a transparent conductive substrate and a hole transport layer, a perovskite light absorption layer, an electron transport layer, an interface modification layer and a metal electrode stacked thereon in sequence, characterized in that the material of the hole transport layer comprises the cuprous iodide described in claim 6.

[0014] Furthermore, the material of the perovskite light absorbing layer is ABX 3 , where A includes CH 3 NH 3 + 、CH(NH 2 ) 2+ 、CH(NH 2 ) 2 + , Cs + , Rb + At least one of, B includes Pb 2+ Sn 2+,Ge 2+ At least one of, X comprises at least one of Cl, Br, and I;

[0015] The material of the electron transport layer includes [6,6]-phenyl-C 61 -Methyl butyrate;

[0016] The material of the interface modification layer includes 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline;

[0017] The material of the metal electrode includes at least one of gold, silver, copper and aluminum.

[0018] The present invention also provides a method for preparing the above-mentioned inverse perovskite solar cell, characterized in that it comprises:

[0019] A hole transport layer, a perovskite light absorption layer, an electron transport layer, an interface modification layer and a metal electrode are sequentially prepared on the surface of a transparent conductive substrate.

[0020] Preferably, the transparent conductive substrate is also pretreated, and the pretreatment includes first rinsing the transparent conductive substrate with deionized water and ultrasonically treating it, and then placing it in anhydrous ethanol, isopropanol, acetone and anhydrous ethanol in sequence for ultrasonic treatment, and placing it in anhydrous ethanol solution for static storage after ultrasonic cleaning. When in use, it is also blown dry with high-purity nitrogen, and then subjected to ultraviolet ozone treatment.

[0021] It should be noted that the preparation methods of the hole transport layer, perovskite light absorption layer, electron transport layer and interface modification layer are conventional methods in the art, and are prepared by spin coating a solution or dispersion of the corresponding layer material and then annealing.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a new method for preparing cuprous iodide: cuprous iodide is prepared by using an organic cuprous salt and an organic iodine amine compound. The results show that the cuprous iodide prepared by this method, as a hole transport layer material for an inverse perovskite solar cell, reduces the surface roughness of the hole transport layer and makes the nucleation sites on the surface of the hole transport layer more dispersed, which is beneficial to the film crystallization of the perovskite and improves the film quality.

[0024] Compared with cuprous iodide prepared by traditional methods, the hole transport layer constructed by cuprous iodide prepared in the present invention has a very suitable energy level match with perovskite, which is more conducive to the extraction and transmission of carriers, etc., thereby improving the photoelectric conversion efficiency of the overall perovskite solar cell.

[0025] The hole transport layer constructed by cuprous iodide prepared by the present invention has good inherent stability and will not undergo adverse chemical reactions with perovskite at the interface. The obtained inverse perovskite solar cell has the advantages of excellent stability, high conversion efficiency, good thermal stability and low defect density, which also lays a good foundation for maintaining long-term stability in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 The schematic diagram of the structure of the inverted perovskite solar cell prepared by the present invention is shown;

[0028] Figure 2 A schematic diagram of the energy levels of each layer of the inverted perovskite solar cell prepared by the present invention is shown;

[0029] Figure 3 The XRD pattern of cuprous iodide prepared in Example 1 is shown;

[0030] Figure 4 The transmission electron microscope image of cuprous iodide prepared in Example 1 is shown;

[0031] Figure 5 The transmission spectrum of the cuprous iodide thin film prepared in Example 1 is shown;

[0032] Figure 6 The XRD pattern of the perovskite light absorbing layer prepared in Example 1 is shown;

[0033] Figure 7 The scanning electron microscope image of the perovskite light absorbing layer prepared in Example 1 is shown;

[0034] Figure 8 The current density-voltage curve of the inverted perovskite solar cell prepared in Example 1 is shown;

[0035] Fig. 9 The current density-voltage curve of the inverse perovskite solar cell prepared in the comparative example is shown;

[0036] Fig.10 The efficiency diagram of the inverse perovskite solar cell prepared in Example 1 at different time periods under extreme conditions of 85° C. and 30% RH is shown. DETAILED DESCRIPTION

[0037] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0038] In the present invention, cuprous trifluoromethanesulfonate toluene complex and cuprous iodide were purchased from Aladdin, methyl iodide was purchased from Greatcell, and the remaining materials were directly purchased from the market unless otherwise specified. 61 -Butyric acid methyl ester is abbreviated as PCBM; 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is abbreviated as BCP. These contents will not be repeated in the examples.

[0039] The following will be combined with the specific embodiments of the present invention and the drawings of the specification to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] A method for preparing an inverse perovskite solar cell comprises the following steps:

[0042] (1) Substrate pretreatment: Use a glass cutter to cut large pieces of fluorine-doped SnO 2 The glass (FTO) was cut into uniform sizes of 1.5 cm × 1.5 cm, and then the cut FTO surface was rinsed with deionized water and ultrasonically treated for 10 min using an ultrasonic machine. It was then placed in anhydrous ethanol, isopropanol, acetone and anhydrous ethanol for ultrasonic treatment for 10 min in sequence. After ultrasonic cleaning, it was placed in anhydrous ethanol solution for static storage.

[0043] (2) Preparation of hole transport layer: 10 mmol of cuprous trifluoromethanesulfonate toluene complex and 1 mmol of iodomethylamine were mixed and transferred to 1 mL of isopropanol and stirred for 30 min. The reaction product was centrifuged and washed with isopropanol for 3 times, and then the product was dried in a drying oven at 120°C for 30 min to obtain cuprous iodide powder. Then the cuprous iodide powder was dispersed in isopropanol to prepare a 1 mg / mL cuprous iodide isopropanol dispersion; the FTO stored in step (1) was taken out and dried with high-purity nitrogen, and treated with ultraviolet ozone for 15 min, and then 50 μL of cuprous iodide isopropanol dispersion was taken out with a liquid gun and dropped onto the treated FTO surface, and then spin-coated with a sizing machine at a speed of 4000 rpm for 30 s, and then annealed on a heating table at 100°C for 30 min to obtain a hole transport layer.

[0044] (3) Preparation of perovskite light-absorbing layer: FAPbI 3 , CsPbI 3 and MAPbBr 3 Dissolve them in a mixed solvent of DMF and DMSO in a volume ratio of 9:1 to prepare a perovskite precursor solution with a concentration of 1.3 mol / L. After fully dissolving, 3 3% molar concentration of CsPbI was added to the solution 3 and 3% molar concentration of MAPbBr 3 , stirring for 45 minutes to make it evenly mixed to obtain a perovskite solution, then using a pipette to draw 45 μL of the perovskite precursor solution and evenly drip it onto the hole transport layer prepared in step (2), and using a gel coater to spin coat at a speed of 5000 rpm for 30 seconds. At the last 10 to 20 seconds, quickly and evenly drip 200 μL of chlorobenzene anti-solvent, and then move to a heating plate and anneal at 100°C for 30 minutes to obtain a perovskite light absorbing layer.

[0045] (4) Preparation of electron transport layer: Weigh 30 mg of PCBM powder sample, then add 1 mL of chlorobenzene solution, stir evenly and filter to prepare 30 mg / mL PCBM solution. Then use a pipette to draw 35 μL and evenly add it to the perovskite light absorption layer prepared in step (3), use a gelling machine to spin coat, the speed is 3000 rpm, the spin coating time is 30 s, and then move to a hot plate and anneal at 100 ° C for 10 min to obtain a PCBM electron transport layer.

[0046] (5) Preparation of interface modification layer: First, weigh 0.5 mg of BCP powder sample, then add 1 mL of trifluoroethanol solution, stir evenly and filter to prepare 0.5 mg / mL BCP solution. Then use a pipette to draw 50 μL and evenly add it to the electron transport layer prepared in step (4), use a gel coater to spin coat, the speed is 5000 rpm, the spin coating time is 30 s, and then move to a hot plate and anneal at 70 ° C for 5 min to obtain a BCP interface modification layer.

[0047] (6) Preparation of metal electrode: Using a vacuum coating apparatus, a layer of silver metal electrode layer is uniformly deposited on the electron transport layer prepared in step (5) by thermal evaporation under vacuum conditions. The film thickness monitor shows that the thickness of the electron layer is 150 to 200 nm.

[0048] Figure 1 A schematic structural diagram of the prepared inverse perovskite solar cell is shown. Figure 2 A schematic diagram of the energy levels of each layer of the prepared inverse perovskite solar cell is shown. The valence band of the CuI hole transport layer and the perovskite are very close, which is more conducive to promoting the extraction and transportation of carriers.

[0049] Example 2

[0050] The method is basically the same as Example 1, except that cuprous acetate is used to replace cuprous trifluoromethanesulfonate toluene complex in the step of preparing the hole transport layer.

[0051] Example 3

[0052] The method is basically the same as Example 1, except that in the step of preparing the hole transport layer, cuprous diphenyl phosphate is used to replace cuprous trifluoromethanesulfonate toluene complex.

[0053] Example 4

[0054] The method is basically the same as Example 1, except that iodoformamidine is used to replace iodomethylamine in the step of preparing the hole transport layer.

[0055] Example 5

[0056] The method is basically the same as Example 1, except that methyl iodide is replaced by phenylethylamine hydroiodide in the step of preparing the hole transport layer.

[0057] Comparative Example

[0058] The method is basically the same as Example 1, except that in the step of preparing the hole transport layer, the prepared cuprous iodide powder is replaced by commercial cuprous iodide powder.

[0059] Test Case

[0060] The diffraction peaks of cuprous iodide obtained in the step of preparing the hole transport layer in Example 1 were observed using an X-ray diffractometer. The results are as follows: Figure 3 As shown, it can be seen that two peaks belonging to cuprous iodide are displayed at diffraction angles of 25.57° and 42.21°, representing the (111) and (220) crystal planes, respectively. In particular, the main peak (111) crystal plane of cuprous iodide has extremely strong crystallinity, which also proves the successful preparation of cuprous iodide.

[0061] The microscopic morphology of the cuprous iodide obtained in the step of preparing the hole transport layer in Example 1 was observed using a transmission electron microscope. The results are as follows: Figure 4 As shown, it can be clearly seen that the cuprous iodide nanoparticles are aggregated together in the form of clusters.

[0062] The transmission spectrum of the cuprous iodide hole transport layer prepared on FTO in Example 1 was characterized. Figure 5 As shown, it can be seen that the hole transport layer constructed by cuprous iodide has high optical transmittance, which can reduce the light absorption loss of the titanium ore absorption layer and is beneficial to improving the device performance.

[0063] After the perovskite light absorbing layer was prepared in Example 1, the diffraction peak of the perovskite light absorbing layer was observed using an X-ray diffractometer and the surface morphology of the perovskite light absorbing layer was observed using a scanning electron microscope. The results were as follows: Figure 6 and 7 As shown. Figure 6 It can be seen from the figure that the prepared perovskite light-absorbing layer has a diffraction characteristic peak that completely matches the perovskite and has good crystallinity. Figure 7 It can be seen that the perovskite grains are flat and smooth, with good crystallinity.

[0064] JV test: At AM1.5, the active layer effective area is 0.06cm 2 Under the conditions, the inverse perovskite solar cells of Example 1 and the comparative example were subjected to current density-voltage tests. The current density-voltage curves of Example 1 and the comparative example are shown as follows: Figure 8 and Fig. 9 Example 1 shows an open circuit voltage of 1.128 V and a short circuit current density of 23.46 mA cm -2 , the fill factor is 0.779, and the champion efficiency is 20.56%. However, the open circuit voltage of the comparative example is 1.056 V, and the short circuit current density is 23.71 mA cm -2 , the filling factor is 0.678, and the champion efficiency is 17%. Compared with the comparative example, the various performances of the embodiment are significantly improved, which is due to the good crystallinity of perovskite and the rapid carrier transport between interfaces.

[0065] The efficiency of the inverse perovskite solar cell of Example 1 was also tested under extreme conditions of 85°C and 30% RH. Fig.10 It can be seen that under this extreme condition, the device can still maintain a working efficiency of more than 80% after 500 hours, which shows that the battery of the embodiment has excellent thermal stability.

[0066] In summary, the present invention provides a new method for preparing cuprous iodide, and the inverse perovskite solar cell using cuprous iodide as a hole transport layer has high power conversion efficiency and excellent thermal stability, which also makes it have great potential in practical applications.

[0067] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing cuprous iodide, characterized in that: for, The organic cuprous salt, the organic iodine amine compound and the solvent are mixed and reacted to obtain cuprous iodide; The organic cuprous salt is at least one of cuprous acetate, cuprous diphenyl phosphate, and cuprous trifluoromethanesulfonate toluene complex; The solvent is isopropanol.

2. The method for preparing cuprous iodide according to claim 1, wherein The organic iodine amine compound includes at least one of iodine methylamine, iodine formamidine, and phenethylamine hydroiodide.

3. The method for preparing cuprous iodide according to claim 1, wherein The molar concentrations of the organic cuprous salt and the organic iodine amine compound are 5-20 mol / L and 0.5-2 mol / L respectively.

4. A cuprous iodide, characterized in that The method is obtained by the preparation method according to any one of claims 1 to 3.

5. Use of the cuprous iodide according to claim 4 in an inverse perovskite solar cell.

6. An inverted perovskite solar cell, comprising a transparent conductive substrate and a hole transport layer, a perovskite light absorption layer, an electron transport layer, an interface modification layer and a metal electrode stacked thereon in sequence, characterized in that: The material of the hole transport layer includes the cuprous iodide as claimed in claim 4.

7. The inverted perovskite solar cell according to claim 6, characterized in that: The material of the perovskite light absorbing layer is ABX3, wherein A includes CH3NH3 + 、CH(NH2) 2+ 、CH(NH2)2 + , Cs + , Rb + At least one of B including Pb 2+ Sn 2+ ,Ge 2+ At least one of, X includes Cl - Br - ,I - At least one of; The material of the electron transport layer includes [6,6]-phenyl-C 61 -Methyl butyrate; The material of the interface modification layer includes 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; The material of the metal electrode includes at least one of gold, silver, copper and aluminum.

8. A method for preparing an inverse perovskite solar cell according to claim 6 or 7, characterized in that: include, A hole transport layer, a perovskite light absorption layer, an electron transport layer, an interface modification layer and a metal electrode are sequentially prepared on the surface of a transparent conductive substrate.

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