A third generation solar cell based on wet-chemically etched Si nanowires and sol-gel derived Cu₂ZnSnS₄ thin films

Monophase Cu₂ZnSnS₄ (CZTS) thin films have been succesfully deposited on both soda lime glass substrate and Si nanowire (NW) arrays by a simple and cost-effective production route based on a combination of sol-gel and spin-coating technique. X-ray diffraction and energy dispersive X-ray analysis studies have revealed that post-annealing process at 350 °C is a sufficient temperature for the growth of a stoichiometric mono-phase CZTS thin film. The band gap energy of the films was found to be 1.55 eV. Following the optimization of CZTS thin films, they were deposited on the Si-NWs as an absorber layer for the fabrication of n-Si-NWs/p-CZTS structured solar cell. From the recorded I-V characteristics of the constructed solar cells under standard condition (A.M 15G), the power conversion efficiency was found to be 1.0 ± 0.1%.