Effect of Rb doping on modulating grain shape and semiconductor properties of MAPbI3 perovskite layer

•Conductivity type of MAPbI3 could be tuned from n-type to p-type with Rb doping.•Hole concentration and mobility could be controlled by adjusting Rb concentration.•Conversion of dominant crystal structure would occur at range of 1.5–1.8 M.•A slight blue shift of the PL peak with increase in Rb concentration was observed. In this paper, a novel morphology transformation of MAPbI3 films which were doped with Rb and prepared by spin coating on a “mp-TiO2/bl-TiO2/FTO” substrate was demonstrated. A slight blue shift of the PL peak for MAPbI3 with increase in RbI concentration was shown. The electronic properties of perovskite films, especially, conductivity type could be significantly tuned from n-type to p-type by doping with Rb. Carrier concentration and mobility could be controlled by adjusting dopant concentration. The investigation of the semiconductor properties of perovskite may shine light on future rational design of novel and more efficient perovskite solar cells.