Journal of Materials Science, Vol.53, No.19, 13617-13630, 2018
Mechanochemical approach to a Cu2ZnSnS4 solar cell absorber via a "micro-nano" route
The present study demonstrates a mechanochemical "micro-nano" approach toward the future solar cell absorber material Cu2ZnSnS4 (CZTS) with up-scaling potential. For this purpose, synthetic copper sulfide CuS and tin sulfide SnS nanoparticles along with microsized zinc metal and elemental sulfur as solid precursors were utilized. These precursors were milled in a planetary ball mill in an argon atmosphere for a period of 1-240 min. Moreover, we compare it to a "micro" approach starting from the elements and maintaining the same milling conditions. The phase composition of reaction mixtures was analyzed by X-ray diffractometry. The final products of syntheses were further analyzed by means of scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy. The phase purity of the prepared materials was verified by confocal Raman microscopy. In both cases, a polydisperse system of a nearly stoichiometric Cu2ZnSnS4 phase was readily obtained after 60 min of milling with only traces of unreacted Cu2-xS phases. Based on the results, we conclude there is no definite difference in reaction speed. However, the crystallite size and optical properties of the prepared CZTS samples slightly differ when various precursors are used.