Tuning PbI2 layers by n-butanol additive for improving CH3NH3PbI3 light harvesters of perovskite solar cells

PbI2 layers with a mesoporous structure are facilely prepared by spin coating of PbI2 in DMF solution with n-butanol additive, which can improve crystallization and modify the orientation of the MAPbI3 layers produced by an interface reaction. The recombination and charge transfer process are improved in the perovskite solar cells with these harvester layers.