title: Nonstoichiometric acid-base reaction as reliable synthetic route to highly stable CH3NH3PbI3perovskite film.
abstract: Perovskite solar cells have received worldwide interests due to swiftly improved efficiency but the poor stability of the perovskite component hampers the device fabrication under normal condition. Herein, we develop a reliable nonstoichiometric acid-base reaction route to stable perovskite films by intermediate chemistry and technology. Perovskite thin-film prepared by nonstoichiometric acid-base reaction route is stable for two months with negligible PbI2-impurity under ∼65% humidity, whereas other perovskites prepared by traditional methods degrade distinctly after 2 weeks. Route optimization involves the reaction of PbI2with excess HI to generate HPbI3, which subsequently undergoes reaction with excess CH3NH2to deliver CH3NH3PbI3thin films. High quality of intermediate HPbI3and CH3NH2abundance are two important factors to stable CH3NH3PbI3perovskite. Excess volatile acid/base not only affords full conversion in nonstoichiometric acid-base reaction route but also permits its facile removal for stoichiometric purification, resulting in average efficiency of 16.1% in forward/reverse scans.
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Long
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Tiankai
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, 999077 Hong Kong, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Chun-Fai
authors.initials: CF
authors.lastname: Ng
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Thomas C W
authors.initials: TC
authors.lastname: Mak
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, 999077 Hong Kong, China.
authors.forename: Keyou
authors.identifier: 0000-0003-4380-7325
authors.initials: K
authors.lastname: Yan