A High-Sensitivity PtNPs@CsCu2I3 Single-Crystal UV Photodetector for Precision Sunscreen Protection Monitoring

Abstract

Addressing the public health challenge posed by skin cancer is the urgent necessity to devise bending and wearable ultraviolet (UV) photodetectors capable of monitoring the carcinogenic UV in everyday life on a real-time basis and with individualized coverage. This paper proposes a new plasmonic enhancement scheme using platinum nanoparticles (PtNPs)-decorated on the one-dimensional (1D) CsCu$_2$I$_3$ single-crystals (SCs) to high-performance and highly stable UV photodetection. Surface-coated PtNPs provide a plasmonic response with a maximum at 341 nm, which is essentially in coincidence with the absorption edge of CsCu$_2$I$_3$. This alignment contributes to a considerable increase in the light harvesting and carrier generation/separation efficiency. The optimized PtNPs@CsCu$_2$I$_3$ photodetector is characterized by outstanding performance under 340 nm illumination at 5 V bias, achieving a responsivity of 26.32 A/W, a specific detectivity of \(5.97 \times 10^{13}\) Jones, and ultrafast sub-millisecond response times (510 \(\mu\)s rise / 619 \(\mu\)s decay). Moreover, the detector is very environmentally stable, and the performance of the detector remains more than 95\% of the original 90 days ambient air storage in the absence of encapsulation. In a practical demonstration for sunscreen UV-blocking assessment, the device shows high linearity (\(R^2 = 0.99\)) and reliable accuracy in the different sunscreens with varying strength factors. This contribution does more than merely offer an efficient pathway of achieving high-performance copper-based perovskite photodetectors, although their possible applications in the real-world may be wearable health-commerce tags, environmental sensors, and optical communication structures.