Synthesis, Growth and Characterization of Cu2CoSnS4 Thin Films via Thermal Evaporation Method

•Polycrystalline CCTS powder was successfully obtained by direct fusion method.•CCTS thin films were synthesized via thermal evaporation method followed by thermal treatment in sulfur atmosphere.•CCTS films have absorption coefficient of over 105 cm-1 in visible range.•CCTS films have optical band gap in the range 1.40-1.43 eV with p-type conductivity.•The MB photodegradation efficiency of CCTS sample under solar irradiation is 73%. Quaternary sulfide Cu2CoSnS4 (CCTS) thin films were deposited by vacuum thermal evaporation on heated substrates. The substrates temperatures are ranged from room temperature to 200 °C. After what, the as-deposited films were sulfurized under vacuum at 450 °C to optimize the stoechiometric stannite CCTS phase. The crystalline structure of the sulfurized CCTS thin films was examined by X-ray diffraction technique and Raman spectroscopy. Surface morphological, elemental compositions and optical properties were explored by scanning electron microscopy, energy dispersive spectroscopy and spectrophotometer UV-VIS-NIR, respectively. X-ray diffraction and Raman analysis confirm that the sulfurization process leads to the formation of single CCTS phase. Optical results show high absorption coefficients of 105 cm-1 in the visible range with direct optical band-gap in the range 1.40-1.43 eV. In addition, the p-type conductivity of CCTS thin films was confirmed by hot probe method. The degradation of methylene blue in the presence of post-sulfurized samples was found in the range of 62-73%. Optical and Photocatalytic properties proves that post-sulfurized samples are suitable for application in photovoltaic and photocatalysis.