Bandlike Transport in FaPbBr₃ Quantum Dot Phototransistor with High Hole Mobility and Ultrahigh Photodetectivity

Halide perovskites have been widely explored for numerous optoelectronic applications among which phototransistors have appeared as one of the most promising light signal detectors. However, it is still a great challenge to endow halide perovskites with both mobility and high photosensitivity because of their high sensitivity to moisture in ambient atmosphere. Here, we explore an FAPbBr₃ perovskite quantum dot (QD) phototransistor with bandlike charge transport and measure a dark hole mobility of 14.2 cm² V^-1 s^-1 at ambient atmosphere. Attaining both high mobility and good optical figures of merit, a detectivity of ∼10¹⁶ Jones is achieved, which is a record for halide perovskite nanocrystals. Simple A-site salt (FABr) treatments offer a mechanism for connecting between perovskite QDs for better charge transfer in high-quality devices. All of these important properties are superior to most advanced inorganic semiconductor phototransistors, indicating a promising future in optoelectronic applications.