Nonstoichiometric acid-base reaction as reliable synthetic route to highly stable CH₃NH₃PbI₃ perovskite 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 PbI₂ with excess HI to generate HPbI₃, which subsequently undergoes reaction with excess CH₃NH₂ to deliver CH₃NH₃PbI₃ thin films. High quality of intermediate HPbI₃ and CH₃NH₂ abundance are two important factors to stable CH₃NH₃PbI₃ perovskite. 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.

SUBMITTER: Long M 

PROVIDER: S-EPMC5476796 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature