Large grained and high charge carrier lifetime CH3NH3PbI3 thin-films: implications for perovskite solar cells

Spin coated perovslcite thin films are known to have an issue of pinholes & poor morphology control which lead to poor device-to-device repeatability, that is an impediment to scale-up. In this work, Methylamine vapor annealing process is demonstrated which consistently leads to high-quality perovskite thin-films with an average grain-size of 10-15 mu m. The improvement in film morphology enables improvement in effective carrier recombination lifetime, from 21 its in as-deposited films to 54 mu s in vapor-annealed films. The annealed films with large-grains are also more stable in ambient conditions. Devices made on annealed perovskite films are very consistent, with a standard deviation of only 0.7%. Methylamine vapor annealing process is a promising method of depositing large-grain CH3NH3PbI3 films with high recombination lifetime and the devices with improved performance. (C) 2017 Elsevier B.V. All rights reserved.