GROWTH OF <font>Cu2ZnSn(S,Se)4</font> THIN FILMS BY A SIMPLE ECO-FRIENDLY SOLUTION ROUTE METHOD

A simple and hydrazine-free solution-based approach for depositing Cu2ZnSnS4 (CZTS) and Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers is reported. The process involves incorporating metal salts (Cu(CH3COO)2, Zn(CH3COO)2, SnCl2) and thiourea into a single pyridine-based solution, spin-coating a precursor film, and sulfurizing with sulfur powders or selenizing using Se pellets in an inert atmosphere, to form the desired CZTS or CZTSSe films. X-ray diffraction and Raman spectra studies show that kesterite CZTS and CZTSSe are formed after sulfurization and selenization, respectively. The selenized CZTSSe displays higher crystallinity than the sulfurized CZTS. Photovoltaic devices (glass/ Mo /CZTSSe/ CdS /i- ZnO /n- ZnO /A) employing the solution precursor selenized at 500&#176;C have yielded power conversion efficiency of 1.44% under AM 1.5 illumination.