Quantitative analysis of Ag-doped SnS thin films for solar cell applications

This work reports the changes in the properties of Ag-doped SnS thin films (SnS:Ag), and CdS/SnS solar cells with an Ag dopant concentration in the absorber varied from 0 to 6 wt.% in steps of 3 wt.% prepared by the nebulizer-assisted spray pyrolysis method (NSP). X-ray diffraction (XRD) studies confirm the SnS:Ag (3 wt.%) thin film has a higher crystallite size than the undoped and SnS:Ag (6 wt.%) thin film. An atomic force microscope (AFM) image shows SnS:Ag (3 wt.%) film possesses larger-sized grains than other samples. The energy-dispersive X-ray analysis (EDS) confirms the presence of the constituent elements in the SnS:Ag thin films. PL analysis revealed the films possess the band edge as well as the other defect-related emissions of SnS. The Ag doping facilitates the tunability in absorption and decreases in optical bandgap for the SnS:Ag (3 wt.%) film. Hall measurements provide the low resistivity of 3.31 Ωcm, the high charge carrier concentration of 1.56 × 1017 cm−3, and high mobility of 12.1 cm2 V−1 s−1 for 3 wt.% Ag-doped SnS film. The better photovoltaic conversion efficiency of 0.285% was observed for the device prepared with SnS:Ag (3 wt.%) thin film compared to other samples due to enhanced absorption, optimum bandgap, and better electrical properties.