Hydrothermal deposition method for preparing semitransparent Sb2S3 solar cell by taking DMAC (dimethylacetamide) as auxiliary solvent

Abstract

According to the method, an auxiliary solvent N, N-dimethylacetamide (DMAC) is added into a precursor solution for hydrothermal deposition of the antimony sulfide thin film to adjust the deposition rate, so that the thickness of the thin film is optimized, the morphology of the thin film is improved, the crystallinity is improved, the defect density of the thin film is reduced, and the performance of a device is improved. The antimony sulfide solar cell comprises a conductive substrate (including FTO and the like), an electron transport layer, an antimony sulfide solar cell absorption layer and a counter electrode. The DMAC can promote grain polymerization of the antimony sulfide thin film, increase the grain size and reduce electric leakage channels of the solar cell. And DMAC has the effect of adjusting the deposition rate, so that the reaction is slower to obtain a more appropriate thickness of the absorption layer. By constructing an effective antimony sulfide thin film solar cell structure, the device performance of the antimony sulfide solar cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of antimony sulfide solar cells, specifically involving a method for using N,N-dimethylacetamide (DMAC) to assist in controlling the deposition rate of antimony sulfide during hydrothermal deposition, thereby improving film quality and film thickness. Background Technology

[0002] In today's society, where environmental awareness is increasingly strong, solar cells, as a new energy source, have received increasing attention. A solar cell is a device that converts solar energy into electrical energy and is widely used in homes, industry, and agriculture. Antimony sulfide thin-film solar cells are particularly popular due to their excellent photoelectric performance and superior absorption coefficient (10⁻⁶). 5 cm -1 Antimony sulfide (Sb) has attracted much attention due to its abundant elemental reserves (S content is 260 ppm) and excellent stability. Its unique one-dimensional crystal structure helps reduce the main defects in typical thin-film solar cells. According to the Shockley-Queisser theory, Sb₂S₃ single-junction solar cells can achieve a theoretical power conversion efficiency (PCE) of 33.7%. Based on these unique properties, antimony sulfide thin-film solar cells have the potential to be developed into a next-generation solar cell and applied on a large scale. However, the actual efficiency of antimony sulfide solar cells still falls far short of the theoretical efficiency; therefore, improving the performance of antimony sulfide solar cells remains crucial.

[0003] For heterojunction thin-film solar cells, the quality of the absorber layer and the interfacial contact jointly determine the cell's performance. The absorber layer should possess a suitable band gap, a large grain size, high crystallinity, and excellent carrier transport characteristics. The quality of antimony sulfide thin films largely depends on the preparation method, deposition formulation, and post-processing. Furthermore, the thickness of the antimony sulfide thin film should not be too thick, otherwise it will increase its series resistance and severely degrade device performance. Therefore, the thickness of the antimony sulfide thin film should be controlled within the optimized range of 100-200 nm.

[0004] Currently, the most efficient method for fabricating devices is hydrothermal deposition. However, hydrothermal deposition also has significant drawbacks: the deposition process of antimony sulfide films within a sealed autoclave is unobservable and uncontrollable, making the reaction entirely dependent on the state of the precursor solution. In hydrothermal deposition, deionized water is typically chosen as the solvent. However, numerous studies have shown that antimony sulfide films prepared using deionized water contain oxide impurities. These oxide impurities may introduce more defects, increasing the recombination rate of electron-hole pairs and thus affecting carrier transport and lifetime. The idea of ​​adding auxiliary solvents essentially involves adjusting the Sb content by adding other ions. 3+The concentration of N,N-dimethylacetamide (DMAC) can regulate the reaction kinetics by dissolving both sulfur and antimony sources, and also by adjusting the concentration of Sb. 3+ The concentration of N,N-dimethylacetamide (DMAC) plays a role in regulating the deposition rate. Currently, there are no reports on improving the hydrothermal deposition rate of antimony sulfide thin films by adding DMAC as an auxiliary solvent. This project aims to improve device performance by adding DMAC as an auxiliary solvent to the precursor solution for hydrothermal deposition of antimony sulfide thin films, thereby regulating the deposition rate, optimizing film thickness, improving film morphology, increasing crystallinity, and reducing the defect density of the film.

[0005] In summary, antimony sulfide thin-film solar cells still face the challenge of improving power conversion efficiency. Poor absorption layer quality and unsuitable absorption layer thickness can significantly reduce device performance, thus limiting the development of antimony sulfide thin-film solar cells. Summary of the Invention

[0006] To improve the quality of the absorber layer and thus enhance the performance of antimony sulfide solar cells, this invention employs a hydrothermal deposition method with the addition of N,N-dimethylacetamide (DMAC) as an auxiliary solvent to adjust the deposition rate. This results in a larger absorber layer grain size, a flatter film surface, and a more suitable thickness, thereby improving the device performance of antimony sulfide solar cells.

[0007] The primary objective of this invention is to obtain a higher quality antimony sulfide thin film that is highly suitable for use in solar cells.

[0008] The second objective of this invention is to improve the device performance of antimony sulfide thin-film solar cells by using a hydrothermal deposition method with N,N-dimethylacetamide (DMAC) as an auxiliary solvent, thereby increasing their short-circuit current density and power conversion efficiency.

[0009] In a first aspect, the present invention provides a method for preparing antimony sulfide thin films by hydrothermal deposition using N,N-dimethylacetamide (DMAC) as an auxiliary solvent, the steps of which include:

[0010] (1) Cleaning of substrate material;

[0011] (2) Prepare the precursor solution for antimony sulfide thin film growth;

[0012] (3) The absorber layer was prepared by hydrothermal deposition;

[0013] (4) Fix the substrate in a closed container containing the precursor solution;

[0014] (5) Place the sealed container described in step (4) in a constant temperature device and grow it for a specific time;

[0015] (6) The substrate after growth in step (5) is removed and cleaned to obtain an antimony sulfide film.

[0016] A second aspect of the present invention provides a solar cell based on a DMAC-improved antimony sulfide absorber layer, the device comprising:

[0017] Base;

[0018] Electron transport layer;

[0019] Antimony sulfide absorber layer;

[0020] Counter electrode.

[0021] base The substrate of this invention is not specifically limited, as long as it does not limit the purpose of this invention. It can be conductive glass, flexible plastic substrate, stainless steel, etc., and preferably, FTO glass is used.

[0022] Electron transport layer The electron transport layer of this invention is not specifically limited, as long as it does not restrict the purpose of this invention. For example, cadmium sulfide, zinc oxide, and tin dioxide, which have good electron transport performance, can be used.

[0023] Antimony sulfide absorber layer There are no specific limitations on the antimony sulfide light-absorbing layer material, as long as it does not limit the purpose of this invention. For example, antimony sulfide materials with direct carrier transport paths and band matching with the upper and lower layers can be used, preferably materials with potassium antimony tartrate as the antimony source.

[0024] counter electrode The counter electrode (or back electrode) of this invention is not specifically limited, as long as it does not limit the purpose of this invention. Aluminum paste, gold, and carbon can be used. Preferably, gold particles are used. The thickness of the counter electrode is 100 nm.

[0025] Compared with the prior art, the present invention has the following advantages and positive effects:

[0026] (1) The present invention prepares a thin film structure of antimony sulfide with larger grain size and better crystallinity, which can improve the performance of antimony sulfide solar cell devices;

[0027] (2) With fewer interface defects, DMAC can regulate the deposition reaction rate, making the hydrothermal deposition of antimony sulfide films slower and more conducive to obtaining ideal film thickness.

[0028] (3) DMAC has good solubility and can dissolve antimony source and sulfur source without reacting with them, which is conducive to a more complete hydrothermal deposition reaction.

[0029] (4) DMAC has a tendency to aggregate antimony sulfide film grains into larger grains, and larger grain size is beneficial to reduce leakage loss.

[0030] (5) The method of the present invention is simple, low in cost and easy to implement. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings, wherein:

[0032] Figure 1 This is a schematic diagram of an antimony sulfide thin-film solar cell with DMAC-assisted solvent hydrothermal deposition.

[0033] Figure 2 These are XRD patterns of traditional hydrothermal deposition and hydrothermal deposition with the addition of auxiliary solvents. Detailed Implementation

[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions. Unless otherwise defined or stated, the technical and scientific terms used herein have the same meaning as those familiar with the art. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the methods of the present invention.

[0035] Example 1: Preparation of antimony sulfide solar cells using the present invention

[0036] (1) Clean the FTO conductive glass sheet with glass cleaner, deionized water, acetone and anhydrous ethanol, and blow it dry.

[0037] (2) Place the FTO obtained in step (1) vertically into a beaker and pour in 80 ml of the prepared cadmium nitrate and thiourea precursor solution.

[0038] (3) Place the beaker from step (2) into a constant temperature water bath and grow it at 65°C for 20 minutes. Then take out the FTO, rinse it with deionized water and anhydrous ethanol and dry it to obtain the cadmium sulfide electron transport layer.

[0039] (4) Place the cadmium sulfide electron transport layer obtained in step (3) on a hot plate at 400°C and anneal for 10 min.

[0040] (5) Place the substrate obtained in step (4) obliquely into the inner liner of the autoclave, and pour in 40 ml of the prepared potassium antimony tartrate, sodium thiosulfate and DMAC precursor solution.

[0041] (6) Place the autoclave from step (5) into an oven and grow it at 120°C for 150 min. Then take out the substrate, rinse it with deionized water and anhydrous ethanol, and dry it to obtain the antimony sulfide absorption layer.

[0042] (7) Place the antimony sulfide absorber layer obtained in step (6) on a hot plate at 350°C and anneal for 10 min.

[0043] (8) A gold electrode was prepared on top of the absorption layer by thermal evaporation.

[0044] Example 2: Preparation of antimony sulfide thin films using the present invention

[0045] (1) Clean the FTO conductive glass sheet with glass cleaner, deionized water, acetone and anhydrous ethanol, and blow it dry.

[0046] (2) Place the FTO obtained in step (1) into the inner liner of the autoclave and pour in 40 ml of the prepared precursor solution of potassium antimony tartrate, sodium thiosulfate and DMAC. The concentration of potassium antimony tartrate is 50 mM, the concentration of sodium thiosulfate is 100 mM and the optimal amount of DMAC is 10 mL.

[0047] (3) Place the autoclave from step (2) into an oven and grow it at 120°C for 150 min. Then take out the substrate, rinse it with deionized water and anhydrous ethanol, and dry it to obtain the antimony sulfide absorption layer.

[0048] (4) Anneal the antimony sulfide absorber layer obtained in step (3) on a hot plate at 350°C for 10 min. This yields a recrystallized, dense antimony sulfide film, the XRD pattern of which is shown in the attached instruction manual. Figure 2 As shown, compared with conventional hydrothermal deposition, the antimony sulfide film obtained by hydrothermal deposition with the addition of DMAC auxiliary solvent has significantly stronger peak diffraction intensity at

[211] and

[221] . The stronger diffraction peaks of these two [hk1] oriented grains are considered to be beneficial to carrier transport.

Claims

1. A hydrothermal deposition method for preparing translucent Sb₂S₃ solar cells using N,N-dimethylacetamide (DMAC) as an auxiliary solvent, characterized in that, The battery structure includes: Base; Electron transport layer; Antimony sulfide absorber layer; Counter electrode.

2. The electron transport layer as described in claim 1 may be made of cadmium sulfide (CdS).

3. A hydrothermal deposition method for preparing semi-transparent Sb₂S₃ solar cells using DMAC as an auxiliary solvent, characterized in that, Includes the following steps: (1) Clean the FTO conductive glass sheet with glass cleaner, deionized water, acetone and anhydrous ethanol, and blow it dry. (2) Place the FTO obtained in step (1) vertically into a beaker and pour in the prepared cadmium nitrate and thiourea precursor solution. (3) Place the beaker from step (2) into a constant temperature water bath for growth, then take out the FTO, rinse it with deionized water and anhydrous ethanol and dry it to obtain the cadmium sulfide electron transport layer. (4) Place the cadmium sulfide electron transport layer obtained in step (3) on a hot plate for annealing. (5) Place the substrate obtained in step (4) obliquely into the inner liner of the autoclave, and pour in the prepared potassium antimony tartrate, sodium thiosulfate, and 10-40 ml of DMAC precursor solution. (6) Place the autoclave from step (5) into an oven for growth, then remove the substrate, rinse it with deionized water and anhydrous ethanol and dry it to obtain the antimony sulfide absorption layer. (7) Place the antimony sulfide absorber layer obtained in step (6) on a hot plate for annealing. (8) A gold electrode was prepared on top of the absorption layer by thermal evaporation.

4. Step (2) as described in claim 3, characterized in that, The mixed solution poured into the beaker is 80 ml.

5. Step (3) as described in claim 3, characterized in that, The growth temperature for preparing the cadmium sulfide electron transport layer was 65℃, and the growth time was 20 min.

6. Step (4) as described in claim 3, characterized in that, The annealing temperature of the cadmium sulfide electron transport layer was 400℃, and the time was 10 min.

7. Step (5) as described in claim 3, characterized in that, The growth temperature for preparing the antimony sulfide absorber layer was 120℃, and the growth time was 150 min.

8. Step (6) as described in claim 3, characterized in that, The antimony sulfide absorber layer was annealed at 350℃ for 10 minutes.

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