PerspectiveMaterials Chemistry

How hybrid perovskites get their groove

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Science  23 Sep 2016:
Vol. 353, Issue 6306, pp. 1365
DOI: 10.1126/science.aai7682

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Summary

Polycrystalline thin films of hybrid organic-inorganic lead halide perovskites (HOIPs) show remarkable performance in semiconductor devices from light-emitting diodes to solar cells (1, 2). Despite modest charge carrier mobilities (3) and a known presence of defect sites (4), polycrystalline HOIP films prepared under comparatively crude conditions exhibit minority carrier lifetimes and diffusion lengths comparable with those of high-purity single-crystal GaAs (3). What makes HOIPs so special? On page 1409 of this issue, Zhu et al. (5) argue that the answer may lie in the rotational motion of the dipolar organic cations in the perovskite lattice. These motions seem to screen charge carriers from defects and other scattering potentials, much like ions screen electric fields in solution.