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Controllable Growth of Perovskite Films by Room‐Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells
Author(s) -
Yang Bin,
Dyck Ondrej,
Poplawsky Jonathan,
Keum Jong,
Das Sanjib,
Puretzky Alexander,
Aytug Tolga,
Joshi Pooran C.,
Rouleau Christopher M.,
Duscher Gerd,
Geohegan David B.,
Xiao Kai
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201505882
Subject(s) - materials science , crystallinity , annealing (glass) , heterojunction , optoelectronics , planar , bilayer , perovskite (structure) , thin film , photovoltaic system , spin coating , chemical engineering , composite material , nanotechnology , chemistry , ecology , biochemistry , computer graphics (images) , membrane , computer science , engineering , biology
A two‐step solution processing approach has been established to grow void‐free perovskite films for low‐cost high‐performance planar heterojunction photovoltaic devices. A high‐temperature thermal annealing treatment was applied to drive the diffusion of CH 3 NH 3 I precursor molecules into a compact PbI 2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI 2 . A controllable layer‐by‐layer spin‐coating method was used to grow “bilayer” CH 3 NH 3 I/PbI 2 films, and then drive the interdiffusion between PbI 2 and CH 3 NH 3 I layers by a simple air exposure at room temperature for making well‐oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6 %, which is comparable to values reported for thermally annealed perovskite films.