Organic solvent vapor treatment of lead iodide layers in the two-step sequential deposition of CH3NH3PbI3-based perovskite solar cells

The two step sequential deposition of CH3NH3PbI3-based perovskite solar cells has been modified by applying toluene and chlorobenzene vapors during the preparation of PbI2 films leading to the growth of the PbI2 grain size. PbI2 films treated with these solvent vapors have more surface area with which CH3NH3I can react leading to a more desirable perovskite layer morphology. This resulted in a significant increase in the performance of the corresponding perovskite solar cell devices where the average power conversion efficiency was enhanced from 5.2% for the control device up to 8.4 and 10.2% for toluene and chlorobenzene-treated devices, respectively.