Ultrahigh-sensitivity PtNPs@CsCu2I3/AlGaN van der Waals heterojunction self-powered photodetector enabling precision solar-blind UV photometric quantification

High-fidelity quantitative detection in the solar-blind ultraviolet regime is essential for radiation-hardened optical systems and secure communications. This study demonstrates a pioneering self-powered ultraviolet photodetector utilizing an engineered CsCu2I3/AlGaN van der Waals heterojunction (vdWh) architecture, enabling high-precision light irradiance measurement. Through strategic integration of size-controlled platinum nanoparticles (PtNPs) that induce localized surface plasmon resonances enhancement, the optimized device achieves remarkable performance metrics at zero bias: a photoresponsivity of 200 mA/W, a specific detectivity of 1.65 × 1012 Jones as well as ultrafast response speed with rise/fall times of 400/540 μs under 254 nm illumination, surpassing the majority of its competitors. The unencapsulated detector exhibits robust thermal-humidity stability under ambient conditions, demonstrating exceptional reliability. A prototype light-intensity monitoring system, integrating this PtNPs@CsCu2I3/AlGaN vdWh detector with customized signal processing circuitry, demonstrates exceptional measurement accuracy with absolute error < 5.0 μ W/cm2 and relative error < 5.0%, respectively. This work develops high-performance solar-blind ultraviolet photodetectors using eco-friendly lead-free perovskites with tailored interfaces, and establishes an integration framework bridging these devices to deep-ultraviolet photonics and radiation-resistant applications.