Study On Preparation Of Light Absorbing Layer And Control Of Device Structure In Antimony Chalcogenide Thin-film Solar Cells

In order to help achieve the carbon peaking and carbon neutrality goals,accelerating the development of clean and green solar-cell materials has become a general trend.Antimonyl chalcogenide semiconductor materials（Sb₂S₃,Sb₂Se₃ and Sb₂（S,Se）₃）have become ideal light absorbers for new-generation solar cells,due to their high absorption coefficient,excellent stability,low toxicity and abundant reserves,etc.At present,antimonyl chalcogenide solar cells have attracted much attention and developed rapidly in the photovoltaic field.Among them,the maximum efficiency of Sb₂Se₃ and Sb₂（S,Se）₃solar cells has exceeded 10%,but the efficiency of Sb₂S₃ solar cells is still relatively low and havn’t made any progress since reaching 7.5%in 2014.Nevertheless,the highly efficient antimonyl chalcogenide solar cells are typically achieved using extremely expensive and unstable organic hole transporting layers,resulting in poor stability of the solar cell devices when exposed to air or moisture.Therefore,in view of the two major problems of low efficiency and poor stability faced by antimony chalcogenide solar cells,we carried out the following work based on the material selection,method design and process optimization for light absorption layer and hole transport layer:（1）Using fresh precursor materials for antimony（antimony potassium tartrate）and combined sulfur（sodium thiosulfate and thioacetamide）,we created a unique chemical bath deposition procedure to prepare Sb₂S₃ thin film.Due to the complexation of sodium thiosulfate and the advantageous hydrolysis cooperation between these two sulfur sources,the heterogeneous nucleation and the S^2-releasing processes are boosted.As a result,there are noticeable improvements in the deposition rate,film morphology,crystallinity,and preferred orientations.Additionally,the improved film quality efficiently lowers charge trapping capacity,suppresses carrier recombination,and prolongs carrier lifetimes,leading to significantly improved photoelectric properties.Ultimately,the power conversion efficiency exceeded 8%for the first time since 2014,reaching the highest level of the Sb₂S₃solar cells so far.This study is expected to shed new light on the fabrication of high-quality Sb₂S₃ film and further efficiency improvement in Sb₂S₃ solar cells.（2）MnS is designed to replace conventional organic materials as the hole transporting layer to construct Sb₂（S,Se）₃ solar cells.In this work,the MnS film was prepared by spin coating method.The influences of precursor scheme,raw material proportion,solution concentration,annealing conditions on the MnS film and the corresponding Sb₂（S,Se）₃devices were explored,and the optimal process parameters were determined.Based on this method,the maximum efficiency of MnS-Sb₂（S,Se）₃ solar cells reaches 8.15%,achieving the conversion efficiency of all inorganic Sb2（S,Se）3 solar cells exceeding 8%for the first time,which still has a certain gap with the efficiency of Sb₂（S,Se）₃ solar cells based on traditional organic hole transporting layer.Therefore,this work suggests that it is necessary to make some improvements on the preparation method of MnS thin film to further enhance its film quality and improve its photoelectric characteristics as the hole transporting layer.（3）High-quality inorganic MnS hole-transport thin films were prepared by vacuum thermal evaporation method for constructing high-efficiency Sb₂（S,Se）₃ solar cells.A low-temperature air-annealing process for the evaporated MnS layer was found to result in a significant positive effect on the power conversion efficiency of Sb₂（S,Se）₃ solar cells,due to its better-matched energy band alignment after partial oxidation,which promotes the hole extraction and transport.The maximum efficiency of all inorganic Sb₂（S,Se）₃ solar cells prepared by this method is 9.24%,reaching a high level in all inorganic antimony chalcogenide solar cells.Morever,the Sb₂（S,Se）₃ solar cells based on MnS inorganic hole transporting layer exhibits excellent stability,and its efficiency loss after stored in air for 45days is reduced by 28%than that based on traditional organic hole transporting layer.