Design rules for the broad application of fast (<1 s) methylamine vapor based, hybrid perovskite post deposition treatments

Abstract

While organo-metal halide perovskite photovoltaics have seen rapid development, growth of high quality material remains a challenge. Herein, we report a facile post deposition treatment utilizing coordination between methylamine (CH₃NH₂) vapor and CH₃NH₃PbI₃ perovskite that rapidly improves film quality, enhancing power conversion efficiency (PCE) by ∼9%. We further comprehensively analyze the physical impact of this process with regard to the material's optoelectronic properties and its detailed microstructural changes. Connecting this with an analysis of the source of organo-metal halide perovskite reactivity toward the vapor as well as phase behavior as a function of CH₃NH₂ vapor pressure and time, we provide design rules for the broad, rational extension of this process to new systems and scales.