TY - JOUR
T1 - Controllable growth of perovskite films by room-temperature air exposure for efficient planar heterojunction photovoltaic cells
AU - Yang, Bin
AU - Dyck, Ondrej
AU - Poplawsky, Jonathan
AU - Keum, Jong
AU - Das, Sanjib
AU - Puretzky, Alexander
AU - Aytug, Tolga
AU - Joshi, Pooran C.
AU - Rouleau, Christopher M.
AU - Duscher, Gerd
AU - Geohegan, David B.
AU - Xiao, Kai
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - 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 CH3NH3I precursor molecules into a compact PbI2 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 PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I 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. A breath of fresh air: Simple room-temperature air exposure can drive the interdiffusion between perovskite precursor layers and crystallize the perovskite thin films. The obtained perovskite films show high crystallinity and well-aligned orientation. The devices with and without a TiO2 electron transporting layer yielded high efficiencies of 15.6 % and 13.8 %, respectively.
AB - 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 CH3NH3I precursor molecules into a compact PbI2 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 PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I 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. A breath of fresh air: Simple room-temperature air exposure can drive the interdiffusion between perovskite precursor layers and crystallize the perovskite thin films. The obtained perovskite films show high crystallinity and well-aligned orientation. The devices with and without a TiO2 electron transporting layer yielded high efficiencies of 15.6 % and 13.8 %, respectively.
KW - air exposure
KW - in situ X-ray diffraction
KW - perovskites
KW - photovoltaic devices
KW - thin films
UR - http://www.scopus.com/inward/record.url?scp=84983096316&partnerID=8YFLogxK
U2 - 10.1002/anie.201505882
DO - 10.1002/anie.201505882
M3 - Article
AN - SCOPUS:84983096316
SN - 1433-7851
VL - 54
SP - 14862
EP - 14865
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 49
ER -