Effects of Annealing on Characteristics of CuZnSnSe/CHNHPbI/ZnS/IZO Nanostructures for Enhanced Photovoltaic Solar Cells.

This paper presents new photovoltaic solar cells with CuZnSnSe/CHNHPbI(MAPbI)/ZnS/IZO/Ag nanostructures on bi-layer Mo/FTO (fluorine-doped tin oxide) glasssubstrates. The hole-transporting layer, active absorber layer, electron-transporting layer, transparent-conductive oxide layer, and top electrode-metal contact layer, were made of CuZnSnSe, MAPbI perovskite, zincsulfide, indium-doped zinc oxide, and silver, respectively. The active absorber MAPbI perovskite film was deposited on CuZnSnSe hole-transporting layer that has been annealed at different temperatures. TheseCuZnSnSe filmsexhibitedthe morphology with increased crystal grain sizesand reduced pinholes, following the increased annealing temperature. When the perovskitefilm thickness was designed at 700 nm, the CuZnSnSe hole-transporting layer was 160 nm, and the IZO (indium-zinc oxide) at 100 nm, and annealed at 650 °C, the experimental results showed significant improvements in the solar cell characteristics. The open-circuit voltage was increased to 1.1 V, the short-circuit current was improved to 20.8 mA/cm, and the device fill factor was elevated to 76.3%. In addition, the device power-conversion efficiency has been improved to 17.4%. The output power was as good as 1.74 mW and the device series-resistance was 17.1 Ω.