High-performance capacitive humidity sensor based on h-BN/PVP nanocomposite films

Humidity detection is crucial for environmental monitoring, industrial control, and healthcare. This study investigates the fabrication process and performance characteristics of a capacitive interdigitated electrode humidity sensor based on hexagonal boron nitride (h-BN)/polyvinylpyrrolidone (PVP) nanocomposite films. A liquid-phase ultrasonic-assisted exfoliation method was employed to prepare uniformly dispersed h-BN/PVP composites. The humidity-sensitive film was formed on the interdigital electrodes by the drop-coating process, and its morphology, structure, and interfacial interactions were systematically characterized. Results demonstrate remarkably high sensitivity (maximum sensitivity change of 2673.94 pF/%RH), rapid response/recovery time (0.1/1.2 s), excellent long-term stability, and low hysteresis within the 11–97% RH range. The outstanding performance of the sensor is attributed to the synergistic effect between the hydrophilic functional groups of h-BN nanosheets and the PVP polymer chains, as well as the porous microstructure of the composite film, which enhances water molecule adsorption and ion transport efficiency. This study provides an effective material design strategy for developing highly sensitive, fast-response humidity sensors.