Solar radiation, especially ultraviolet (UV) light, is a major hazard for most skin-related cancers. The growing needs for wearable health monitoring systems call for a high-performance real-time UV sensor to prevent skin diseases caused by excess UV exposure. To this end, here a novel self-powered p-CuZnS/n-TiO UV photodetector (PD) with high performance is successfully developed (responsivity of 2.54 mA W at 0 V toward 300 nm). Moreover, by effectively replacing the Ti foil with a thin Ti wire for the anodization process, the conventional planar rigid device is artfully turned into a fiber-shaped flexible and wearable one. The fiber-shaped device shows an outstanding responsivity of 640 A W , external quantum efficiency of 2.3 × 10 %, and photocurrent of ≈4 mA at 3 V, exceeding those of most current UV PDs. Its ultrahigh photocurrent enables it to be easily integrated with commercial electronics to function as a real-time monitor system. Thus, the first real-time wearable UV radiation sensor that reads out ambient UV power density and transmits data to smart phones via wifi is demonstrated. This work not only presents a promising wearable health monitor, but also provides a general strategy for designing and fabricating smart wearable electronic devices.

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Although lithium-oxygen batteries possess ah igh theoretical energy density and are considered as promising candidates for next-generation power systems,t he enhancement of safety and cycling efficiency of the lithium anodes while maintaining the high energy storage capability remains difficult. Here,w eo vercome this challenge by cross-stacking aligned carbon nanotubes into porous networks for ultrahighcapacity lithium anodes to achieve high-performance lithiumoxygen batteries.T he novel anode shows ar eversible specific capacity of 3656 mAh g À1 ,approaching the theoretical capacity of 3861 mAh g À1 of pure lithium. When this anode is employed in lithium-oxygen full batteries,t he cycling stability is significantly enhanced, owingt ot he dendrite-free morphology and stabilized solid-electrolyte interface.This work presents anew pathway to high performance lithium-oxygen batteries towards practical applications by designing cross-stacked and aligned structures for one-dimensional conducting nanomaterials.

Flexible fiber batteries with self-powering functionality will offer new opportunities for next-generation wearable electronic devices. Here, we present a high-capacity aqueous Zn-ion battery fiber that can directly harvest energy from...