P-type charge transport and selective gas sensing of all-inorganic perovskite nanocrystals

The remarkable optoelectronic property of all-inorganic halide perovskite nanocrystals (NCs) has inspired the exploration of these materials for a wide range of applications. However, the low conductivity of perovskite NCs thin film is regarded as the Achilles' heel, hindering further development in electronic usage. To address this issue, we employed sequential treatments of methyl acetate soft soaking and Ostwald ripening on CsPbBr₃NC thin films, which improve the transport property and dramatically enhance the carrier lifetime from 11.56 to 112.5 ns. The field-effect transistor (FET) based on resulting CsPbBr₃NCs thin film exhibits p-type carrier mobility of 0.023 cm²V^-1s^-1and ON/OFF ratio up to ∼10⁴, which is on par with the bulk perovskite-based FETs. Furthermore, as a proof of concept, we demonstrate that the p-type CsPbBr₃NCs feature high gas-sensing selectivity to detect NO₂with a detection limit down to 0.4 ppm. The appealing charge-transport properties of these CsPbBr₃NCs underscore their potentials for versatile applications.