Ultra-Broadband Self-Trapped Exciton Emission of (TPA)₂Cu₄Br₆ for UV Single-Pixel Imaging

Ultraviolet (UV) spectral imaging plays a pivotal role in multidisciplinary research spanning physics, materials science, biology, and medicine, serving as a cornerstone for non-line-of-sight information detection and imaging. Single-pixel imaging (SPI), owing to its optical simplicity and robustness against scattering, has emerged as a promising solution for UV spectral imaging. However, conventional SPI systems predominantly operate in the visible spectrum and face critical challenges in UV applications, including intricate modulation, focusing difficulties, and costly instrumentation, severely limiting their resolution and encoding capacity. To address these limitations, we propose utilizing (TPA)₂Cu₄Br₆, a broadband self-trapped exciton (STE) emitter, as a UV-to-visible wavelength converter in SPI systems. This material achieves exceptional photoluminescence quantum yield (94.26%), ultrabroad emission (450–900 nm), millisecond-scale lifetime, and remarkable robust thin-film encapsulation stability. Capitalizing on its strong spectral overlap with silicon-based detectors, we engineered a simplified imaging architecture that eliminates the need for optical filters or multi-source switching. When integrated with human eye-inspired compressive sensing algorithms, the system enables a high-resolution image reconstruction (128 × 128 pixels) under low-intensity excitation, with a sampling rate as low as 20%. This work not only pioneers the application of broadband emitters in invisible-light optical systems but also establishes a material platform for high-efficiency SPI design.