<p>The development of broadband ultraviolet (UV) detection and imaging systems is in high demand for applications such as security early warning and environmental monitoring. However, conventional UV detection and imaging systems suffer from limited bandgap tunability, leading to poor compatibility with deep UV wavelengths due to their restricted spectral response. To address this, we fabricated a composite glass device with multi-bandgap design, where Gd³⁺ ions bridge the bandgap mismatch between the host glass and embedded Cs₃Cu₂I₅ nanocrystals (NCs), enabling efficient carrier cascade cooling and the conversion of deep UV photons into visible light. Owing to an energy transfer efficiency approaching 100%, the device exhibits a spectral response from 180 to 350 nm, including the vacuum UV region ( &lt; 200 nm) that was previously inaccessible to single-band UV detectors. Moreover, the visible-light transparency and scalability of the glass subtract enable seamless integration with silicon-based photoresistors and complementary metal-oxide semiconductor imaging systems, achieving large-area, high-resolution (34.7 lp mm⁻¹) imaging performance that significantly surpasses conventional UV detector arrays. This work therefore establishes a scalable strategy for the rational design and fabrication of stable, ultra-broadband UV detectors, paving the way for next-generation UV detection and imaging technologies.</p>