Polar rotor scattering as atomic-level origin of low mobility and thermal conductivity of perovskite CH₃NH₃PbI₃.

ABSTRACT: Perovskite CH₃NH₃PbI₃ exhibits outstanding photovoltaic performances, but the understanding of the atomic motions remains inadequate even though they take a fundamental role in transport properties. Here, we present a complete atomic dynamic picture consisting of molecular jumping rotational modes and phonons, which is established by carrying out high-resolution time-of-flight quasi-elastic and inelastic neutron scattering measurements in a wide energy window ranging from 0.0036 to 54 meV on a large single crystal sample, respectively. The ultrafast orientational disorder of molecular dipoles, activated at ∼165 K, acts as an additional scattering source for optical phonons as well as for charge carriers. It is revealed that acoustic phonons dominate the the

SUBMITTER: Li B 

PROVIDER: S-EPMC5497077 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature