A recent report by Cahen and co-workers is examined that finds the diffusion constant for proton migration in methylammonium lead triiodide single crystals to be 2 × 105 -fold greater than that previously reported by Sadhu et al. By comparing the conversion of single crystals versus microcrystalline samples, it is concluded that proton diffusion in macroscopic single crystals is accelerated by the presence of defects acting as high-diffusivity paths.
Keywords: deuteration; halide perovskites; ion diffusion; proton diffusion.
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