Research On Fabrication Of Copper Zinc Tin Sulfide(Selenide)Thin Films By None-Hydrozine Solution Approach And Application For Superstrate-Type Solar Cells

Cu₂ZnSnS₄（CZTS）has become a new thin film solar cell material because of its high optical absorption coefficient,suitable band gap,low cost and abundant reserves.Therefore,it is an ideal absorbing layer material for copper indium gallium selenium（CIGS）thin film solar cell.At present,CZTS-based solar cells prepared by anhydrous hydrazine solution have the highest efficiency,but hydrazine solution is flammable and explosive,which is inconvenient to use.Therefore,the development of non-toxic,environmentally friendly solution system to prepare high efficiency CZTS-based thin film solar cells has become a research hotspot.In this thesis,CZTS precursor films were prepared by molecular precursor solution method.Improvement of crystallinity of thin films by post-treatment（nitrogen annealing,sulfidation annealing,selenization annealing）.The CZTSSe thin films with large grain size were obtained,and the corresponding devices were fabricated.The photovoltaic performance of the device is preliminarily explored.This paper is mainly composed of three aspects:1.Preparation of CZTS precursor film:screening from the experimental process,using TGAm as solvent,Cu O,Zn O and Sn O as precursors,the precursor solution was obtained after dissolution,and CZTS precursor thin films were prepared by spin coating method.The crystallization of precursor film was enhanced after annealing in nitrogen atmosphere.XRD and Raman show that both CZTS precursor films and annealed films in high temperature nitrogen atmosphere are kesterite structure,however,impurities exist in the CZTS film.2.Preparation of Large grain CZTS or CZTSSe films:In this paper,the CZTS precursor thin films were sulfurization/selenization.The films were characterized by XRD,Raman,SEM and EDS.The results show that the materials are all kesterite structure,and the CZTSSe thin films with large grain size（>1μm）are obtained by selenization.3.Device fabrication and photoelectric performance characterization:superstrate type cell:FTO/Ti O₂buffer layer/CZTSSe light absorption layer/Au structure,and solved the problem of thin film solar cell spoiled under sulfur/selenium conditions initially,the highest efficiency of solar cells prepared under selenization is 2.42%.（The electrode area is 9.07 mm²）.