Research On The Preparation Of SnS₂、SnS Photoelectric Films And The Corresponding Solar Cells

In recent years, the study on non-toxic, environmental-friendly tin-sulfur compoundsmaterials has attracted much attention from researchers. Due to its excellent opticalproperties, tin-sulfur compounds are widely used in photoelectric devices such as solarcells. Compared with CdTe、GaAs、CIGS and other film solar cells, the two elements Sn、S are abundant on the earth, non-toxic, cheap and have a good environmentalcompatibility. The direct band gap of SnS is1.3~1.5eV, which is very close to theoptimum bandgap of the solar cells. SnS possesses a high absorption coefficientα>104cm-1, and the photoelectric conversion efficiency can be theoretically up to25%, soSnS can be used as absorbent materials in solar cells. Furthermore, SnS2，a good n-typewide band semiconductor material, is suitably used as window materials in solar cells.Therefore, the study of tin-sulfur compounds thin films enjoys a great importantsignificance and value in developing new solar cells.In this paper, the SnS thin films and SnS2thin films are prepared by the plasmaenhanced chemical vapor deposition (PECVD) combined with solid resources, and thecorresponding heterojunction film solar cells are also prepared. The main work is asfollows：(1) The films are deposited using a self-developed PECVD apparatus. The resourcesin this method are solid source materials, rather than the traditional gas source materials.This improvement can significantly reduce the cost of the deposition, and it also won’tproduce any contamination to the environment.(2) The SnS2thin films are prepared by PECVD with solid source materials. Theinfluence of different substrates, the substrate temperature and the annealing treatment onthe crystal structure, surface morphology, chemical composition and optical properties ofthe SnS2films are systemically investigated and discussed.(3) The SnS thin films are prepared by PECVD with solid tin source materialsSnCl45H2O, SnCl22H2O and solid sulfur source materials Na2S2O3. The influence of thesubstrate temperature and different tin sources on physical and optical properties of theSnS2films are systemically investigated and discussed.(4) The heterojunction film solar cells glass/FTO/n-SnS2/p-SnS/Ag,glass/FTO/n-ZnO/p-SnS/Ag and glass/FTO/n-TiO2/p-SnS/Ag are successfully prepared with the non-porous island structure SnS thin films, combined with three n-typesemiconductor materials: the SnS2thin films, ZnO thin films and TiO2films, respectively.The photoelectric conversion efficiency have been tested and analyzed.In this paper, qualified SnS and SnS2thin films are prepared by PECVD method withsolid sources. We have explored the controlled process parameters of the prepared films,and successfully prepared heterojunction film solar cells, which established a foundationfor industrial production of thin film solar cells.