Formation of CuIn(S_xSe_1-x)₂microcrystals from CuInSe₂nanoparticles by two step solvothermal method

Here we introduced a two-step reaction to synthesize highly crystalline CuIn(S_1-xSe_x)₂(CuInSSe) microcrystals from CuInSe₂nanocrystals. CuInSSe micro particles can be obtained without toxic selenization or sulfurization process and the composition of sulfur and selenium can be easily controlled by varying the amount of precursor at different stages of the reactions. This synthetic route allows a technique that is simple and non-toxic together with the possibility of tuning the composition. XRD, HRTEM and SAED analysis of the final product confirmed the pure phase formation of CuInSSe. EDAX analysis shows the compositions of the final product matched with CuInSSe and the compositions of the product can tune by the reaction parameter. UV-Vis absorption spectra reveals a clear blue shift due to an increase in band gap with the increase of sulfur content. Initial photocurrent response suggests its possibility to be used as absorber materials in thin film solar cells.