On-Wire Halide Perovskite-Heterostructure-Based Photodetectors for Encrypted Communication

All-inorganic lead halide perovskites have generated considerable research interest due to their distinctive electronic and optoelectronic properties. In particular, their inherently soft crystal lattice allows greater tolerance to lattice mismatch, offering promising opportunities for heterostructure formation. Here, we report on a synthesis strategy of the on-wire CsPbCl₃-CsPbI₃ heterostructure via a magnetic-pulling chemical vapor deposition approach. Microstructural characterization reveals the abrupt mutation of compositions along the axial direction of the wire. Microphotoluminescence mapping clearly shows dual-wavelength emissions at 417 and 698 nm at the heterointerface. Optical waveguide investigation indicates that the nanowires have asymmetric transmission characteristics. Additionally, photodetectors based on these heterostructures exhibit superior photoelectric performance, including high responsivity and high detectivity, which not only exhibit a remarkable image-sensing capability but also establish encrypted imaging for innovative applications. All of these findings highlight the potential of combining on-wire band-gap engineering with advanced image techniques, providing insights into the development of next-generation secure information communications.