Publication

Engineering of CH3NH3PbI3 Perovskite Crystals by Alloying Large Organic Cations for Enhanced Thermal Stability and Transport Properties

​Engineering of CH3NH3PbI3 Perovskite Crystals by Alloying Large Organic Cations for Enhanced Thermal Stability and Transport Properties
Wei Peng, Xiaohe Miao, Valerio Adinolfi, Erkki Alarousu, Omar El Tall, Abdul-Hamid Emwas, Chao Zhao, Grant Walters, Jiakai Liu, Olivier Ouellette, Jun Pan, Banavoth Murali, Edward H. Sargent, Omar F. Mohammed, Osman M. Bakr
Angewandte Chemie, 55 (36), pp 10686-10690, (2016)
Wei Peng, Xiaohe Miao, Valerio Adinolfi, Erkki Alarousu, Omar El Tall, Abdul-Hamid Emwas, Chao Zhao, Grant Walters, Jiakai Liu, Olivier Ouellette, Jun Pan, Banavoth Murali, Edward H. Sargent, Omar F. Mohammed, Osman M. Bakr
crystal engineering; organic–inorganic hybrid composites; perovskite phases; photovoltaics
2016
The number of studies on organic–inorganic hybrid perovskites has soared in recent years. However, the majority of hybrid perovskites under investigation are based on a limited number of organic cations of suitable sizes, such as methylammonium and formamidinium. These small cations easily fit into the perovskite's three-dimensional (3D) lead halide framework to produce semiconductors with excellent charge transport properties. Until now, larger cations, such as ethyl-ammonium, have been found to form 2D crystals with lead halide. Here we show for the first time that ethylammonium can in fact be incorporated coordinately with methylammonium in the lattice of a 3D perovskite thanks to a balance of opposite lattice distortion strains. This inclusion results in higher crystal symmetry, improved material stability, and markedly enhanced charge carrier lifetime. This crystal engineering strategy of balancing opposite lattice distortion effects vastly increases the number of potential choices of organic cations for 3D perovskites, opening up new degrees of freedom to tailor their optoelectronic and environmental properties.
DOI: 10.1002/anie.201604880