Improvement in environmental stability and photoluminescence of CH3NH3PbI3 film through Br-doping and nanoporous GaN substrate

Abstract As a new type of solar cell material that has attracted much attention, how to improve the environmental stability and photoluminescence property of organic-inorganic hybrid perovskite materials for large-scale commercial applications is a core issue. This work studied the effect of Br-doping and nanoporous GaN substrate on the environmental stability and photoluminescence property of CH3NH3PbI3 film. The nanoporous GaN substrate was prepared by electrochemical etching method. The CH3NH3PbI3 and CH3NH3PbIxBr3-x films were prepared by the spin coating/CVD method. Then the prepared CH3NH3PbI3 and CH3NH3PbIxBr3-x films were exposed to the natural environment for different time without any protective measures to investigate the effect of Br doping on the environmental stability of the CH3NH3PbI3 films. The morphology and structure of the two prepared films were investigated by using scanning electron microscopy, X-ray photoelectron spectrometer, and X-ray diffractometer. The result of X-ray photoelectron spectrometer showed that the I/Br ratio of the CH3NH3PbIxBr3-x film is approximately 2. The results of scanning electron microscopy and X-ray diffractometer showed that Br-doping significantly enhances the anti-degradation ability of the film. The result of photoluminescence spectroscopy showed that both Br-doping and nanoporous GaN substrate can increase the photoluminescence intensity of the CH3NH3PbI3 film.