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Rapid development of micro‐electromechanical systems increases the need for flexible and durable piezoelectric nanogenerators (f‐PNG) with high output power density. In this study, a high‐performance, flexible, and highly stable f‐PNG is prepared by directly growing the Mg‐doped semi‐insulating GaN nanowires (NWs) on a 30‐µm‐thick tungsten foil using vapor–liquid–solid growth mechanism. The direct growth of NWs on metal foil extends the overall lifetime of the f‐PNG. The semi‐insulating GaN NWs significantly enhance the piezoelectric performance of the f‐PNG by reducing free electron density. Additionally, the direct integration of NWs on the tungsten foil improves the conductivity, resulting in current enhancement (2.5 mA) with an output power density of 13 mW cm−2. The piezoelectric performance of the f‐PNG is investigated under several bending angles, actuation frequencies, continuous vibrations, and airflow velocities. The maximum output voltage exhibited by the f‐PNG is 20 V at a bending angle of 155°. The f‐PNG is connected to the backside of an index finger to monitor finger bending behavior by changing the current density. Depending on its flexibility and sensitivity, the f‐PNG can be used as a health‐monitoring sensor to be mounted on joints (fingers, hands, elbows, and knees) to monitor their repeated bending and relaxation.

Herein, we investigated the influence of changing the number of InGaN/GaN quantum well pairs, optical bandgap tuning, and plasmonic coupling of Au nanoparticles (NPs) with multiquantum wells (MQWs) in photoelectrochemical (PEC) water splitting. MQWs displayed a 2-fold improvement in photocurrent density and applied bias photon-to-current conversion efficiency (ABPE%) as compared to reference GaN at zero bias. Tuning the optical band gap by varying the growth temperature of MQWs has also been shown to influence the performance of PEC water splitting. In comparison to the blue emission, the green emission sample showed a 15% improvement in photocurrent density and ABPE%. Decoration of MQWs with Au NPs significantly enhanced photocurrent density and stability. This is the first time that such a gigantic improvement in stability has been obtained for MQWs in PEC water splitting. Au NP/MQWs showed 80% photocurrent retention after 13.9 h.

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GaN is an important III-V semiconductor for a variety of applications owing to its large direct band gap. GaN nanowires (NWs) have demonstrated significant potential as critical building blocks for...