Department of Physical Chemistry of Solids, Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
Department of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology, Station 6, 1015, Lausanne, Switzerland.
Angew Chem Int Ed Engl. 2017 Jun 26;56(27):7755-7759. doi: 10.1002/anie.201701724. Epub 2017 May 30.
By applying a multitude of experimental techniques including H, N, Pb NMR and I NMR/NQR, tracer diffusion, reaction cell and doping experiments, as well as stoichiometric variation, conductivity, and polarization experiments, iodine ions are unambiguously shown to be the mobile species in CH NH PbI , with iodine vacancies shown to represent the mechanistic centers under equilibrium conditions. Pb and CH NH ions do not significantly contribute to the long range transport (upper limits for their contributions are given), whereby the latter exhibit substantial local motion. The decisive electronic contribution to the mixed conductivity in the experimental window stems from electron holes. As holes can be associated with iodine orbitals, local variations of the iodine stoichiometry may be fast and enable light effects on ion transport.
通过应用多种实验技术，包括 H、N、Pb NMR 和 I NMR/NQR、示踪扩散、反应池和掺杂实验，以及化学计量变化、电导率和极化实验，碘离子被明确证明是 CH3NH3PbI3中的迁移物种，而碘空位被证明是平衡条件下的机械中心。Pb 和 CH3NH3离子对长程输运没有显著贡献（给出了它们贡献的上限），因此后者表现出大量的局部运动。在实验窗口中，混合电导率的决定性电子贡献来自电子空穴。由于空穴可以与碘轨道相关联，因此碘化学计量的局部变化可能很快，并使光对离子输运产生影响。
