Charge transport in mixed metal halide perovskite semiconductors.

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Investigation of the inherent field-driven charge transport behaviour of three-dimensional lead halide perovskites has largely remained challenging, owing to undesirable ionic migration effects near room temperature and dipolar disorder instabilities prevalent specifically in methylammonium-and-lead-based high-performing three-dimensional perovskite compositions. Here, we address both these challenges and demonstrate that field-effect transistors based on methylammonium-free, mixed metal (Pb/Sn) perovskite compositions do not suffer from ion migration effects as notably as their pure-Pb counterparts and reliably exhibit hysteresis-free p-type transport with a mobility reaching 5.4 cm2 V-1 s-1. The reduced ion migration is visualized through photoluminescence microscopy under bias and is manifested as an activated temperature dependence of the field-effect mobility with a low activation energy (~48 meV) consistent with the presence of the shallow defects present in these materials. An understanding of the long-range electronic charge transport in these inherently doped mixed metal halide perovskites will contribute immensely towards high-performance optoelectronic devices.

Charge transport, Field effect transistors, High mobility, Ion migration, Perovskite
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Nat Mater
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Springer Science and Business Media LLC
Engineering and Physical Sciences Research Council (EP/P032591/1)
Royal Society (NIF/R1/192347)
Royal Society (RP\R1\201082)
Engineering and Physical Sciences Research Council (EP/L011700/1)
Engineering and Physical Sciences Research Council (EP/N004272/1)
Engineering and Physical Sciences Research Council (EP/P007767/1)
European Research Council (756962)
EPSRC (EP/T02030X/1)