Preparation And Photovolatic Properties Of Silver Doped And Selenization Cu₂SnS₃ Thin Films

Cu₂SnS₃?CTS?is a promising candidate for next-generation thin-film solar cells due to its excellent optoelectronic properties and high-abundance,nontoxic constituent elements.In recent year,it has been widely used in the fields of solar photo electric conversion and photoelectric detection.Aiming at the problems of low band gap and photoelectric conversion efficiency of CTS materials in the thin-film solar cell.CTS films were successfully prepared by a safe,environmentally friendly and low cost solution synthesis method.Furthermore,The effects of different experimental conditions on the morphology,composition,phase structure,optical and electric properties of CTS films were systematically studied On this basis,solar cell are assembled and their conversion characteristics are explored.Details are as follows:1.The Ag-Cu-Sn-S precursor film was successfully prepared by introducing silver element into the CTS precursor solution,and solar cell devices were assembled on this basis.The results show that Ag doping achieves partial cation replacement.A small amount of Ag doping increases the grain size of the film and the film continuity decreases.When the ratio of silver to copper in the current precursor solution is 0.16,the grain size is large,the film surface is compact and without holes,which leads to higher short-circuit current density and fill factor in the corresponding solar cell device.While excessive Ag doping can inhibit grain growth.As a whole,an enhanced conversion efficiency of 3.99%for ACTS was finally obtained compared to 3.72%for CTS.2.Cu-Sn-S precursor film was obtained by metal salt thiourea method.And it was subjected to high temperature selenization annealing using a tube furnace to prepare Cu₂Sn?S,Se?₃?CTSe?film.The relationship between the quality and photoelectric properties of the absorber layer and the selenization conditions?selenization temperature,selenium dosage,selenization time?were systematically investigated.The results show that the film can be flattened and compacted by increasing the temperature of the selenization annealing in the range of 400-500°C.The proper amount of selenium source can effectively promote the growth of CTSe grains and improve the crystallinity of as prepared film.Prolonging the selenization time can promote the grain growth of CTSe,so that,the thickness of small grain was significantly reduced,even close to zero.At 480°C,the heating rate is 2.4°C/S,the Se particle mass is 100 mg,and the selenization annealing is 10 min.The obtained film show large grain size,smooth and compact surface,and the thickness of small grains and molybdenum selenide are 421 and 351 nm,respectively,which can effectively improve carrier mobility and reduce carrier recombination,and is suitable for the light absorbing layer of solar cells.