Mixed-Dimensional van der Waals Heterostructure for High-Performance and Air-Stable Perovskite Nanowire Photodetectors

An organic-inorganic hybrid perovskite nanowire (NW), CH₃NH₃PbI₃, shows great potential for high-performance photodetectors due to its excellent photoresponse. However, the inefficient carrier collection between the one-dimensional (1D) NWs and metallic electrodes, as well as degradation of the perovskite, limits the viability of the CH₃NH₃PbI₃ NWs for commercial production. Here, we demonstrate a photodetector with a mixed-dimensional van der Waals heterostructure of hexagonal boron nitride (hBN)/graphene (Gr)/1D CH₃NH₃PbI₃, which exhibits excellent responsivity and specific detectivity of up to 558 A/W and 2.3 × 10¹² Jones, owing to the improved carrier extraction at the electrical contact between Gr and the NW. As for the atomic encapsulation of hBN, the device is extremely robust and maintains its outstanding performance for more than 2 months when exposed to air. Moreover, benefitting from the 1D geometry of the CH₃NH₃PbI₃ NW, our device is highly sensitive to polarized light. The mixed-dimensional van der Waals heterostructure, hBN/Gr/1D CH₃NH₃PbI₃, would provide a novel idea and protocol for fabricating high-performance and air-stable photoelectronic devices based on organic-inorganic hybrid perovskite NWs.