Ultrathin wide-bandgap niobate for high-performance photodetection and information encryption.

The remarkable progress in two-dimensional (2D) layered materials has spurred growing interest in extending controlled synthesis to non-layered systems. In particular, ultrathin non‑layered wide‑bandgap oxides have garnered considerable interest owing to their high ultraviolet absorption coefficient and effective spectral selectivity. However, the absence of intrinsic van der Waals gaps and the tendency toward three-dimensional nucleation make the controlled growth of ultrathin non-layered single crystals challenging. To circumvent this limitation, we report a molecular-sieve-assisted molten-salt strategy that enables the controlled fabrication of ultrathin wide-bandgap niobates. The resulting devices exhibit superior performance metrics, featuring an external quantum efficiency of 2.79 × 103%, a specific detectivity of 1.09 × 1013 Jones, fast response, good operational stability, and the capability for solar‑blind imaging. Furthermore, capitalizing on the dual-wavelength photoresponse, we implement a proof-of-concept dual-wavelength physical-layer information-encoding system, demonstrating the feasibility of wavelength-multiplexed UV information transmission.