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

Xiaoxi Wu: Liang Z. Tan, Xiaozhe Shen, Te Hu, Kiyoshi Miyata, M. Tuan Trinh, Renkai Li, Ryan Coffee, Shi Liu, David A. Egger, Igor Makasyuk, Qiang Zheng, Alan Fry, Joseph S. Robinson, Matthew D. Smith, Burak Guzelturk, Hemamala I. Karunadasa, Xijie Wang, Xiaoyang Zhu, Leeor Kronik, Andrew M. Rappe, and Aaron M. Lindenberg; Science Advances, 07/26/17.

Additional Authors: Liang Z. Tan, Xiaozhe Shen, Te Hu, Kiyoshi Miyata, M. Tuan Trinh, Renkai Li, Ryan Coffee, Shi Liu, David A. Egger, Igor Makasyuk, Qiang Zheng, Alan Fry, Joseph S. Robinson, Matthew D. Smith, Burak Guzelturk, Hemamala I. Karunadasa, Xijie Wang, Xiaoyang Zhu, Leeor Kronik, Andrew M. Rappe, and Aaron M. Lindenberg

Abstract:

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.