Integration of ZMSDs into microsystems. Schematics of the (A) device configuration and (B) working principle of the integrated flexible photo-rechargeable system. (C) The normalized light intensity of an LED bulb from the integrated flexible wristband powered by 2 series-connected photo-rechargeable devices. 30 s of photocharge followed by 10 min of continuous lighting. The inset shows the photograph of the wristband [130]. (D) The schematic microcircuit and related resistance changes of hydrogel-based sensor [83]. (E) Digital photographs demonstrating the integration process of the self-powered wearable sensing system [73]. Reproduced with permission.