Effects of co-electrodeposition potential on the physicochemical properties of Cu2CoSnS4 thin films enriched by a theoretical calculation

This work presents the synthesis of Cu2CoSnS4 (CCTS) thin films by the co-electmdeposition technique of Cu-Co-Sn-S on the Fluorine doped Tin Oxide substrates (FTO), followed by a sulfurization for 1 h at 500 degrees C under an argon flow. To study the effect of the electmdeposition potential on the structural, morphological and optical properties of CCTS, this potential was chosen over the range - 0.850 and - 0.950 V (vs SCE) from the cyclic voltammetry curve. The analyzes of the results of several characterizations made subsequently to these samples show the effective formation of the desired phase CCTS but also the effect of the variation of the potential on the different properties of the CCTS samples: X-ray diffraction technique showing characteristic peaks relating to planes (112), (204), (312) and (004) of the CCTS phase, then two characteristic peaks located at 290 and 325 cm(-1) with Raman spectroscopy then the effect of this potential on the optical properties was identified by UV-Visible spectrophotometry which showed that the optical gap values are increased from 1.50 to 1.60 eV when the potential decreases from - 0.85 V to - 0.95 V (vs SCE). In parallel to this experimental study, a theoretical calculation based on the principles of the DFT-GGA mbJ theory has been developed on this CCTS compound, this calculation has permitted to find an optical gap of value 1.68 eV.