Study on the role of additional ions in CH3NH3PbI3_xClx planar solar cells

The present study investigates the influence of the introduced metallic cation and/or halide anion, e.g. Al3+ and Cl-, on the forming mechanism and electro-optical properties of CH(3)NH(3)Pb(I)3 films. Our study shows that introducing of Al impurity into perovskite films produces the intermediate AII(3) that improves the film coverage by expressively slowing down the evaporation of CH3NH3Cl. Likewise, a trace amount of hydrolysis product, i.e. Al2O3, homogenously distribute throughout the precursor as a seed, which is proved to be capable of tuning the crystal orientation and the grain size. Consequently, the introduction of metallic cation and/or halide anion enable the realization of highly crystallized thin film with highly reduced defects, which can effectively alleviate the hysteresis effect that was intractable in planar perovskite cells. (C) 2017 Elsevier Ltd. All rights reserved.