Synthesis Of Sulfur-tin Compounds And Their Applications In Solar Cells

With the development of modern science and technology and the advancement of industrial civilization,fossil energy has become an indispensable form of energy for human beings.However,with the continuous excavation and use of fossil energy,fossil energy is decreasing;At the same time,excessive use of fossil energy has brought irreversible damage to the environment.Solar energy is a new and abundant clean energy source.The use of solar energy will solve the current environmental and energy crisis.Dye-sensitized Solar Cells?DSSCs?have attracted a lot of attention and are extensively investigated because of their low cost,environmental friendship,high efficiency and preparative simplicity.Pt has been commonly used as the counter electrode?CE?for DSSCs due to its high catalytic activity.However,its scarcity and high cost has limited the commercial application of Pt as the CE of DSSCs.In addition,Pt CE can be corroded after long-term exposure to the electrolyte solution of DSSCs,resulting in the performance degradation of the solar cells.Alternative materials to Pt as CE for DDSCs have been intensively researched.Here we report the preparation of tin sulfides and their application as CEs for DSSCs.Three tin sulfides were prepared by heating tin oxides in the presence of CS₂vapor.In the experiment,various tin sulfides?SnS,SnS₂,Sn₂S₃?were obtained by simply adjusting the reaction temperature and the flow rate of carrying gas.Moreover,SnS with different morphologies were generated.SnS microspheres,which were aggregated by lamellar structures,were considered as a promising alternative to Pt as the CE for DSSCs because of its large specific surface area,high conductivity and good catalytic activity.The effect of the preparative parameters on the morphology of the products was discussed.SnS nanosheets were grown directly on the surface of tin foil to be applied as CE for DDSCs,hoping to avoid the process depositing/coating CE materials on substrates.Cyclic voltammetry characterization demonstrated that SnS nanosheets are comparable to Pt in catalyzing I₃^-.A solar cell based on SnS nanosheets CE achieved a photoelectric conversion efficiency?PCE?of 5.42%,while the device with a Pt CE exhibited an efficiency of 7.53%.In addition,we prepared SnS using the hydrothermal method.The microwave absorption characteristic was measured for all the tin sulfides prepared in this study.SnS among three tin sulfides showed the best microwave absorbing performance.When the filling ratio of SnS in wax is 50wt%and the thickness is 2.3 mm,the effective absorption frequency bandwidth is 4.80 GHz.When it has a thickness of7.89 mm,the lowest reflection loss of-32.55 dB is achieved at a frequency of 3.60GHz.Therefore,it is considered to be a new type of microwave absorbing material,which deserves more attention.