Methylamine Post-Deposition Treatments of Vapor-Deposited Perovskite Thin Films

While the development of methylammonium lead iodide (MAPbI(3)) perovskite for photovoltaics has grown rapidly, the growth of high-quality material from vapor processes continues to be difficult due to challenges including crystallinity control. Methylamine (MA) vapor post-deposition treatment is an approach to improve morphology and crystallinity of MAPbI(3) films, producing highly oriented, large grain-size perovskite films. Herein, experiments to characterize the liquefaction and recrystallization produced by treatment are described. Substrate temperature, MA partial pressure, and MA exhaust flow rate have substantial impacts on the film properties. Improved morphology and crystallinity after treatment indicates that substrate temperature plays a significant role in both liquefaction and recrystallization of the film. The result of this study is a useful pathway to fabrication of high-quality MAPbI(3) films from all-vapor process manufacturing.