a novel design of ultrathin zno-based transparent electrode for earth-abundant cu2znSnS4 thin film photovoltaic

The earth-abundant Cu2ZnSnX4 (CZTX where X = Se, S) thin films photovoltaic (PV) has attracted considerable attentions owing its elemental abundancy in Earth’s crust. In this contribution, we demonstrate the CZTS material for PV application with a novel design of ultrathin ZnO-based transparent electrode. A dense and continuous CZTS absorber layer with a thickness of 1.2 µm was prepared using the solution method. The fabrication of CZTS cell was completed with an implementation of a novel ultrathin transparent electrode design comprises multilayer structure of sputtered Al-doped ZnO (AZO) and Ag. This ultimately allows the production of electrodes having a maximum thickness of 100 nm, > 80 % optical transmittance and < 10 Ohm/sq sheet resistance. The EQE of the cells confirmed that the CZTS absorbers exhibit band gap of 1.4 eV. This result also opens an opportunity to reduce material budget for transparent electrode material in high-efficient CZTS PV.