Chirapa BoonthumKusuma PinsuwanJitprabhat PonchaiToemsak SrikhirinPongsakorn KanjanaboosThailand Ministry of EducationMahidol University2019-08-232019-08-232018-06-01Applied Physics Express. Vol.11, No.6 (2018)18820786188207782-s2.0-85047902240https://repository.li.mahidol.ac.th/handle/20.500.14594/45805© 2018 The Japan Society of Applied Physics. Perovskites have attracted considerable attention for application as high-efficiency photovoltaic devices owing to their low-cost and lowtemperature fabrication. A good surface and high crystallinity are necessary for high-performance devices. We examine the negative effects of chemical ambiences on the perovskite crystal formation and morphology. The repeated cation doping (RCD) technique was developed to remedy these issues by gradually dropping methylammonium ions on top of about-to-form perovskite surfaces to cause recrystallization. RCD promotes pinhole-free, compact, and polygonal-like surfaces under various vapor conditions. Furthermore, it enhances the electronic properties and crystallization. The benefits of RCD extend beyond perovskites under vapor ambiences, as it can improve regular and wasted perovskites.Mahidol UniversityEngineeringPhysics and AstronomyArticleSCOPUS10.7567/APEX.11.065503