Methylammonium lead mixed halide films processed with a new composition for planar perovskite solar cells

Abstract

In this work, we propose a new mixed halide precursor composition for MAPbI(3-x)Cl(x) organic/inorganic perovskite (PRV) solar cells. PRV films made with a new precursor composition of (MAI: PbCl2: PbI2 = 2 : 1 : 1) could be crystallized at lower temperature (70 degrees C) and shorter annealing duration (60 min), whereas previous standard composition (MAI: PbCl2 = 3 : 1) requires multi-step and high temperature (from 75 degrees C to 130 degrees C) annealing for longer durations (similar to 100 min). By adopting the suggested composition, much uniform surface morphology of PRV light harvester was obtained even though non-polar solvent washing was not introduced yet. Also, when the suitable toluene washing treatment was introduced, PRV surfaces of highly compact and large crystallites with regular distribution were achieved without any pinhole, which offered significant improvements in fill factor (41 -> 65%) and power conversion efficiency (5.85 -> 9.39%) of PRV cells. The suggested new precursor composition contributing for surface topography can be widely utilized for inverted planar PRV devices with low-temperature and simple processing. (C) 2017 Elsevier B.V. All rights reserved.