Light-induced picosecond rotational disordering of the inorganic sublattice in hybrid perovskites

• Published in: Science advances Vol. 3; no. 7; p. e1602388
• Main Authors: Wu, Xiaoxi, Tan, Liang Z, Shen, Xiaozhe, Hu, Te, Miyata, Kiyoshi, Trinh, M Tuan, Li, Renkai, Coffee, Ryan, Liu, Shi, Egger, David A, Makasyuk, Igor, Zheng, Qiang, Fry, Alan, Robinson, Joseph S, Smith, Matthew D, Guzelturk, Burak, Karunadasa, Hemamala I, Wang, Xijie, Zhu, Xiaoyang, Kronik, Leeor, Rappe, Andrew M, Lindenberg, Aaron M
• Format: Journal Article
• Language: English
• Published: United States AAAS 01.07.2017; American Association for the Advancement of Science
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE; Physical Sciences; SciAdv r-articles; Solar Energy
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.1602388

Femtosecond resolution electron scattering techniques are applied to resolve the first atomic-scale steps following absorption of a photon in the prototypical hybrid perovskite methylammonium lead iodide. Following above-gap photoexcitation, we directly resolve the transfer of energy from hot carriers to the lattice by recording changes in the mean square atomic displacements on 10-ps time scales. Measurements of the time-dependent pair distribution function show an unexpected broadening of the iodine-iodine correlation function while preserving the Pb-I distance. This indicates the formation of a rotationally disordered halide octahedral structure developing on picosecond time scales. This work shows the important role of light-induced structural deformations within the inorganic sublattice in elucidating the unique optoelectronic functionality exhibited by hybrid perovskites and provides new understanding of hot carrier-lattice interactions, which fundamentally determine solar cell efficiencies.