Rubidium copper iodide single crystals for deep-ultraviolet detection and imaging

Deep-ultraviolet (DUV) detectors are indispensable for a wide range of applications, including environmental monitoring, flame warning, and intelligent imaging systems. However, the development of DUV-sensitive materials with high performance, excellent stability, and facile fabrication remains challenging. Here, a novel rubidium copper iodide single crystal is synthesized via a facile solution-based approach and systematically studied both experimentally and theoretically. First-principles calculations reveal a wide bandgap and dispersive electronic bands near the band edges, suggesting efficient carrier transport while maintaining intrinsic DUV selectivity. Consequently, photodetectors fabricated from the single crystals exhibit excellent spectral selectivity in the DUV region, achieving a high responsivity of 3.9 A/W and a specific detectivity of 1.36 × 1012 Jones under 235 nm illumination. More importantly, the devices demonstrate remarkable operational robustness, maintaining stable photoresponse under continuous operation, elevated temperatures, and long-term storage conditions. Benefiting from the high performance, wavelength-selective DUV imaging is successfully demonstrated with high image contrast and resolution. This work highlights the potential of the prepared single crystals and detectors for next-generation DUV optoelectronic sensing and imaging technologies.