Conformal TiO₂ nanolayers on electrospun PVDF fibers via spatial atomic layer deposition for enhanced triboelectric...

Direct-current triboelectric nanogenerators (DC-TENGs) based on metal-semiconductor interfaces provide an effective strategy to eliminate external rectification circuits and enhance energy conversion efficiency; however, precise interfacial regulation and multifunctional integration remain challenging. Herein, we report a conformal TiO₂-coated electrospun PVDF fiber membrane fabricated via spatial atomic layer deposition (SALD) to construct a Schottky junction engineered DC-TENG. Unlike conventional polymer blending or surface modification approaches, SALD enables scalable, low-temperature, and thickness-controlled oxide deposition on three-dimensional fibrous membranes while preserving their porous architecture. The TiO₂ nanolayer acts as an interfacial semiconductor regulator that enhances charge trapping, interfacial polarization, and asymmetric carrier transport at the Al/TiO₂/PVDF interface. The optimized device delivers a peak current of 521 µA and a maximum power density of 40.7 µW cm^-2, representing a 108% enhancement compared with pristine PVDF. The TiO₂/PVDF-TENG output enables direct capacitor charging without external rectifiers, storing up to 2100 µJ in a 1000 µF capacitor. Moreover, stable operation over 6000 contact-separation cycles at 100% relative humidity demonstrates excellent moisture tolerance. The device also exhibits a humidity-dependent linear current response, enabling self-powered environmental sensing. This work highlights SALD-enabled nanoscale oxide interface engineering as an effective and scalable strategy for developing humidity-resilient DC-TENGs with integrated energy-harvesting and sensing functions.