Synthesis of CIGS powder by mechanochemical method

To this day CuIn_1-xGaxSe2 (CIGS) powder used in the manufacture of thick-film CIGS photovoltaic (PV) cells was mainly produced using the solvothermal method. However, this method has drawbacks such as it is expensive and cannot be used to mass produce the CIGS powder. Thus, there is a need to develop a more cost-effective manufacturing process for mass production of CIGS powder to develop stable thick-film CIGS PV cells. The mechanochemical method, which facilitates mass production, can be considered as an alternative for the synthesis of CIGS, but such research results have yet to be reported. In this study, the CIGS synthesis pathway using the mechanochemical method was determined, through which single-phase CIGS was synthesized. Single-phase CIGS was synthesized when the molar ratio x of Ga was below 0.15 in the raw material, CuIn_1-xGaxSe2, but not above this ratio. Also, adding CGS to the CIGS synthesized using the mechanochemical method for a secondary synthesis resulted in increased proportion of Ga in CIGS. Based on the results, it was confirmed that CIGS powder could be synthesized in large quantities at a low cost using the simple process of milling.