Dielectric Engineering of ZnO@ZIF-8 for High-Performance Triboelectric Nanogenerators and Self-Powered Humidity Sensors.

Porous metal oxide-metal-organic framework (MO_x@MOF) hybrids offer synergistic effects that enhance surface charge density, electronic structure, and textural properties, making them ideal for self-powered sensing applications. Here, uniform, and pinhole-free ternary porous ZnO-PTFE@ZIF-8 hybrid films are developed on room-temperature co-sputtered ZnO-polytetrafluoroethylene (PTFE) composite films, where ZnO serves as a self-sacrificial precursor to precisely regulate ZIF-8 (Zn-MeIm₂) growth through solvothermal methods. The resulting TENG achieves a high output power density of 0.67 mW cm^-2, attributed to the synergistic effects of fluorine-rich PTFE and methyl-functionalized ZIF-8, which enhance surface charge density and dielectric response. By tuning PTFE content in the ZnO-PTFE composite, the dielectric constant and triboelectric output is optimized. The ZP60@ZIF-8-based device also demonstrates excellent humidity sensing performance, with a wide detection range (20-99% RH) and ultrahigh sensitivity (R_V% of 19 900%, R_I% of 19 325% at 99% RH). These results position ZP@ZIF-8-based TENGs as promising platforms for next-generation self-powered sensors and smart wearable electronics.