The Changes of Morphology and Composition in Cu(In1-xGax)Se-2 Powder Synthesis by Solvothermal Method

Abstract

To prepare the thin film solar cell by the screen printing method, the synthesis of nano CIGS powder has been frequently studied. Especially, the solvothermal method is normally used in the synthesis of CIGS. However, in the synthesis of CIGS, the experimental studies such as the path of phase formation, the composition change of synthesized CIGS, and the change of powder morphology have rarely been reported. In this study, the changes of phase and morphology of the powders were observed with the ratio of In and Ga ions and the increase of reaction temperature. The phases of CIS and CuIn0.7Ga0.3Se2 were synthesized in a = 0.1. The phase of CIS and two kinds of CIGS coexisted in the range of a = 0.3 similar to 0.7. In a = 0.9, the single phase of CuIn0.9Ga0.1Se2 was synthesized in the same ratio as the source materials. In the case of the a = 0.5 composition, as the concentration of material source and the reaction temperature were increased, the particle size of synthesized CIGS was decreased. The CIGS particles of 200 nm size and the lower aggregate were synthesized in the concentration of 0.01 M at 230 degrees C.