High-performance hybrid nanogenerator for self-powered emergency rescue signaling devices

Harnessing both ultraviolet (UV) light energy from sunlight and the kinetic energy generated by human locomotion—such as walking and jogging—poses a significant challenge. In this study, we present a self-powered hybrid nanogenerator (hNG) that integrates a low-work function polyurethane (FPU)-coated zinc foil, a high-work function polytetrafluoroethylene (PTFE)-covered copper substrate, and an electron-supplementary layer. The synthesized FPU macromolecules exhibit electron-insulating properties while incorporating functional photoisomer and ionic liquid units. By exploiting the synergistic effects of neglected internal photoelectricity and triboelectricity, our hNG achieves impressive performance metrics: an open-circuit voltage of approximately 11 V, a short-circuit current of 130 μA, and a power density of 1 W m −2 under UV illumination at 150 µW cm −2 —similar to natural solar irradiation in Kunming—and during periodic contact-separation cycles at 5 Hz between the FPU and PTFE layers. These results significantly outperform those of traditional FPU-PTFE-based triboelectric nanogenerators. After rectification, the hNG serves as a power source for various applications, including illuminating a YNU-shaped LED strip, powering lasers, and operating a battery-free timer. Notably, outdoor tests demonstrate that the flexible hNG can activate a wireless sound transmitter, an SOS-type LED belt, and a light-and-sound alarm when exposed to direct sunlight. The self-powered sound transmitter effectively broadcasts preset SOS and coordinate signals, which can be received by a radio and displayed on a smartphone. This hybrid nanogenerator not only efficiently harvests wasted UV light energy from sunlight but also shows considerable potential for self-powered emergency rescue signaling applications.