Influences of annealing temperature and thickness on ZnS buffer layers for inverted hybrid solar cells

•Inverted configuration hybrid solar cells were fabricated with ZnS as a buffer layer.•ZnS thin films were prepared by spray pyrolysis method at fixed substrate temperature.•The optical and structure properties of ZnS films were changed with annealing.•The effect of ZnS film annealed on photovoltaic parameters was investigated.•The effect of ZnS film thickness on photovoltaic parameters was investigated. In this study, the photovoltaic performances of inverted type hybrid solar cells fabricated using zinc sulfide (ZnS) as a buffer layer and blend of P3HT(poly(3-hexyl)thiophene), PCBM([6,6]-phenylC61 butyric acidmethylester) as a photoactive layer were reported. ZnS thin films were prepared by spray pyrolysis method at fixed substrate temperature. The effects of annealing under ambient conditions at different temperatures on the optical and structure properties of ZnS films were investigated. When the annealing temperatures of ZnS films were increased from 200 to 500°C, the power conversion efficiency of the inverted type hybrid solar cells was significantly enhanced by improving crystallite and morphology of buffer layer. The effect of ZnS film thickness on photovoltaic parameters of the inverted devices was also investigated.