Sol-gel processed CZTS thin film solar cell on flexible molybdenum foil

By a simple and economical sol-gel and spin-coating technique, fine quality Cu₂ZnSnS₄ (CZTS) thin films were formed on flexible molybdenum foils. The CZTS thin films annealed at 500 °C possessed good compositional, morphological, structural, optical and electrical properties for solar cells. The best flexible solar cell with a structure of Mo foil/CZTS/CdS/ZnO/AZO/Al exhibited a power conversion efficiency of 2.25%, with short circuit current density of 13.52 mA/cm², open circuit voltage of 370 mV and fill factor of 0.45. Meanwhile, the PV performances of the flexible CZTS-based solar cell on molybdenum foil were investigated in detail. - Highlights: • Cu₂ZnSnS₄ films were prepared on Mo foils by sol-gel method. • The best Cu₂ZnSnS₄ solar cell on Mo foil with a PCE of 2.25% was obtained. • The secondary phase ZnS made the electrical properties of the solar cells worse. • Relationships among the photovoltaic performances of the solar cell were studied.