Selective UV Sensing with Eu³⁺-Doped Luminescent Solar Concentrators: From Photocurrent to Image-Based Optical Readout

The development of high-performance ultraviolet (UV) photodetectors typically necessitates multilayer device architectures and external optical filters to achieve reliable selectivity. Herein, we demonstrate a streamlined sensing platform featuring Luminescent Solar Concentrators (LSCs) based on PMMA waveguides doped with Eu³⁺ antenna complexes and interfaced with a silicon solar cell. This architecture yields a self-powered, narrow-band UV photodetector with performance fully competitive with conventional semiconductor devices. A key innovation of this system is its dual-mode operation, enabling UV detection through two independent channels: the electrical photocurrent output of the solar cell and a quantitative image-based optical readout tracking the red Eu³⁺ luminescence. Under white-light illumination, the electrical readout suffers from a background photocurrent offset arising from visible light scattering, whereas the optical readout remains unaffected owing to the spectral selectivity of the Eu³⁺ emission. These transparent, scalable LSC-based devices combine reliable optoelectronic sensing with intuitive visual feedback, offering a versatile platform for large-area UV monitoring.