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A flexible ultraviolet (UV) photodetector based on ZnO nanorods (NRs) as nanostructure sensing materials integrated into a graphene (Gr) field-effect transistor (FET) platform is investigated with high performance. Based on the negative shift of the Dirac point (VDirac) in the transfer characteristics of a phototransistor, high-photovoltage responsivity (RV) is calculated with a maximum value of 3 × 10(8) V W(-1). The peak response at a wavelength of ∼365 nm indicated excellent selectivity to UV light. The phototransistor also allowed investigation of the photocurrent responsivity (RI) and photoconductive gain (G) at various gate voltages, with maximum values of 2.5 × 10(6) A W(-1) and 8.3 × 10(6), respectively, at a gate bias of 5 V. The UV response under bending conditions was virtually unaffected and was unchanged after 10,000 bending cycles at a bending radius of 12 mm, subject to a strain of 0.5%. The attributes of high stability, selectivity, and sensitivity of this flexible UV photodetector based on a ZnO NRs/Gr hybrid FET indicate promising potential for future flexible optoelectronic devices.

Flexible chemical sensors utilizing chemically sensitive nanomaterials are of great interest for wearable sensing applications. However, obtaining high performance flexible chemical sensors with high sensitivity, fast response, transparency, stability, and workability at ambient conditions is still challenging. Herein, a newly designed flexible and transparent chemical sensor of reduced graphene oxide (R‐GO) coupled with organic dye molecules (bromophenol blue) is introduced. This device has promising properties such as high mechanical flexibility (>5000 bending cycles with a bending radius of 0.95 cm) and optical transparency (>60% in the visible region). Furthermore, stacking the water‐trapping dye layer on R‐GO enables a higher response as well as workability in a large relative humidity range (up to 80%), and dual‐mode detection capabilities of colorimetric and electrical sensing for NH3 gas (5–40 ppm). These advantageous attributes of the flexible and transparent R‐GO sensor coupled with organic dye molecules provide great potential for real‐time monitoring of toxic gas/vapor in future practical chemical sensing at room conditions in wearable electronics.

Stretchable piezoelectric nanogenerators (SPENGs) for human kinematics energy harvesting have limited use due to the low stretchability or mechanical robustness and the difficulty of structural design for omnidirectional stretchability. This study reports an efficient, omnidirectionally stretchable, and robust SPENG based on a stretchable graphite electrode on a 3D micropatterned stretchable substrate and a stacked mat of piezoelectric nanofibers. The stacked mat of free‐standing nanofibers is alternatively composed of nanocomposite nanofibers of barium titanate nanoparticles embedded in polyurethane and poly(vinylidene fluoride‐trifluoroethylene) nanofibers. The nanofiber SPENG (nf‐SPENG) exhibits a high stretchability of 40% and high mechanical durability up to 9000 stretching cycles at 30% strain, which are attributed to the stress‐relieving nature of the 3D micropattern on the substrate and the free‐standing stacked hybrid nanofibers. The nf‐SPENG produces a peak open circuit voltage (Voc) and short circuit current (Isc) of 9.3 V and 189 nA, respectively. The nf‐SPENG is demonstrated to harvest the energy from human kinematics while walking when placed over the knee cap of a subject, generating a maximum Voc of 10.1 V. The omnidirectional stretchability, efficiency, facile fabrication process, mechanical durability, environmentally friendly lead‐free components, and response to multimodal straining make this device suitable for self‐powered wearable sensing systems.