Atmospheric Modified Thiol-Based Solution Deposition for Cu 2 ZnSn(S,Se) 4 Absorber Layer

Abandoning the traditional deposition of as-prepared Cu 2 ZnSnS 4 (CZTS) thin films in a glove box, a modified thiol-based solution system suitable for deposition in air is described to further reduce device production costs. In this modified approach, metal salts and thiourea are used as the starting materials and are dissolved in a mixed solution of thioglycolic acid and 2-methoxyethanol, forming a homogeneous precursor solution. The as-deposited CZTS thin films are obtained by spin-coating the precursor solution in air, followed by the selenization process to form large-grained Cu 2 ZnSn(S,Se) 4 thin films. Combining the microstructural results with compositional analyses, the optimal selenization conditions for the Cu 2 ZnSn(S,Se) 4 absorber layer were found to be 540°C and 10 min.