Simultaneous detection of ultraviolet irradiation and vitamin C using an all-carbon-based integrated wearable system powering by a micro-supercapacitor

Ultraviolet (UV) radiation is a harmful exogenous factor for human skin. Wearable UV photodetectors can monitor UV exposure in the surroundings, and wearable vitamin C (VC) sensors tracking the levels in the human body present the potential ability to defend the UV radiation. Herein, we reported on the fabrication of an all-in-one wearable system with a UV photodetector and VC sensor powered by a micro-supercapacitor. Based on direct laser writing carbonization of polyimide sheets, the patterned electrodes and interconnects of the circuit were fabricated by a facile one-step operation, obtaining an all-carbon-based integrated system. Such a system exhibited outstanding energy storage ability (56.2 mu Wh cm-2 at 4.17 mW cm-2), high areal capacitance (1.06 mF cm-2 at 5 mV s-1), satisfying capacitive stability, and good mechanical flexibility. The UV photodetector and the VC sensor were powered to obtain a linear range of UV intensity from 11 to 44 mu W cm-2 (equivalent to Ultraviolet Index 4.4 to 17.6), and VC levels of 1.0-200 mu M with a low limit of detection of 0.83 mu M. Furthermore, the integrated system was successfully applied to the determination of VC in commercial beverage and human sweat samples. This work provided a simple and promising method to fabricate integrated wearable systems for on-site providing information on the UV intensity of the external environment and the VC level of the human body simultaneously.

Automated summary

This study reported the fabrication of an all-in-one wearable system with a UV photodetector and VC sensor powered by a micro-supercapacitor. The system exhibited outstanding energy storage ability, high areal capacitance, and good mechanical flexibility, and was able to simultaneously monitor the UV intensity of the external environment and the VC level in the human body.