Partial coverage methylammonium lead bromide films for solar cell application

Hybrid perovskite compounds as methylammonium lead halides are currently been investigated for different optoelectronic applications. CH3NH3PbBr3 is a promising member because of its electronic structure and large bandgap that gives rise to a high open circuit voltage. Although higher performances can result by using sophisticated processing, one-step methods are particularly interesting because of their easy implementation. Solar cells based on CH3NH3PbBr3 are fabricated using one-step spin coating deposition. Remarkable effect on the morphological, structural, optical and electrical properties is observed by changing the molar ratio of the precursors. Dual film morphology, with micrometer-size CH3NH3PbBr3 crystals embedded in a mesoporous TiO2 background, explains minimal shunting paths and open-circuit voltage reduction. Full perovskite coverage of TiO2 background is not necessary for proper operation