Large Thermal Motion in Halide Perovskites.

ABSTRACT: Solar cells based on hybrid perovskites have shown high efficiency while possessing simple processing methods. To gain a fundamental understanding of their properties on an atomic level, we investigate single crystals of CH₃NH₃PbI₃ with a narrow transition (~5 K) near 327 K. Temperature dependent structural measurements reveal a persistent tetragonal structure with smooth changes in the atomic displacement parameters (ADPs) on crossing T*. We show that the ADPs for I ions yield extended flat regions in the potential wells consistent with the measured large thermal expansion parameter. Molecular dynamics simulations reveal that this material exhibits significant asymmetries in the Pb-I pair distribution functions. We also show that the intrinsically enhanced

SUBMITTER: Tyson TA 

PROVIDER: S-EPMC5571225 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature