Ultra-sensitive ultraviolet organic photodetectors enabled by an expanded spectral window for health monitoring
Excessive ultraviolet (UV) radiation poses significant risks to human health, necessitating highly sensitive detection systems. Organic photodetectors (OPDs) offer high sensitivity and tunable spectral response, but their UV performance is constrained by conventional glass/indium tin oxide (ITO) substrates and electrodes, and insufficient photoactive layer responsivity. Here, we report high-performance UV-OPDs achieved through UV-transparent window and active-layer optimization. Replacing glass/ITO with a UV-transparent window comprising a quartz substrate and PH1000 electrode enhances UV transmittance. Integrating the high UV-responsive blend PM6:Y6:PC71BM as the active layer, the optimal ternary UV-OPD exhibits external quantum efficiency (EQE) exceeding 53% across 280–400 nm, with a peak EQE of 78.29% and responsivity of 214.68 mA/W at 340 nm, alongside a rapid response time of 2.6/2.1 μs. This performance represents the best combination of responsivity and response time reported to date in the UV region. We demonstrate the potential of these UV-OPDs for outdoor real-time UV monitoring. This work presents a promising strategy for developing high-performance UV-OPDs through transparent substrate and electrode engineering, and active-layer optimization.