Transparent, Flexible, and Light-Driven Ionogel Synapse for a Wearable Eyeglass Patch with Real-Time Ultraviolet Monitoring

Continuously unobtrusive monitoring of ultraviolet (UV) radiation is highly desirable for public health. Current UV sensors often compromise optical transparency, mechanical flexibility, and power, limiting their seamless integration into eyewear for real-time and visualized monitoring. Here, we report an intelligent eyeglass patch based on a self-driven ionogel photosynaptic device for UV perception. The synapse is made from a silver nanoparticle-doped ionogel matrix integrated with transparent silver nanowire electrodes. This design ensures both high optical transparency and flexibility, offering a comfortable orientation to curved surfaces. The synergy of the particle-triggered photothermoelectric and nanowire electrode-induced electric double layer contributes to enhance optical absorption and transduce it into amplified, synaptic-like electrical responses upon light exposure. By further attachment onto eyewear, the patch provides continuous, real-time environmental UV monitoring with immediate visual feedback for early warning, all without obstructing vision or compromising comfort. This work offers a practical user-friendly platform to create interactive perception systems for proactive personal health protection.