Co-electrodeposited Ag2SnS3/Mo thin films: optical and electrochemical study: DFT complement

This study concerns the synthesis of the Ag2SnS3 phase on a molybdenum (Mo) substrate, using the coelectrodeposition-sulfurization process by adjusting the [Ag+] at 0.01 M. XRD, Raman, UV-visible and electrochemical analyses have shown that Ag2SnS3/Mo films have been well elaborated with remarkable properties for practical applications. Optically, when [Ag+] was varied between 0.01 and 0.02 M, Ag2SnS3 films present a bandgap change in the range 1.20-1.36 eV, with an absorption coefficient of around 10(-4) cm(-1). Whereas the DFT -> GGA calculation was implemented as a confirmatory theoretical study of the semiconductor and optical aspects of this Ag2SnS3 compound whilst comparing results with experiment. A further attractive property was demonstrated here by an electrochemical study of Ag2SnS3/Mo in Na2SO4 (1 M) under the (- 900, 100) mV/SCE potential window. More specifically, cyclic-voltammetry analysis has highlighted its pseudo-capacitor character with a developed specific capacitance of 800 F g(-1), while galvanostatic charge-discharge shows a drop of around 35% when the current is reduced from 0.5 to 3 mA.