Nanoresistance network-based built-in electric field drive strategy for flexible passive humidity sensors

Current moisture power generation technology faces several limitations, including its dependence on humidity gradients caused by adsorption differences, structural complexities, and the requirement for thick humidity-sensitive layers. These constraints hinder its widespread use in passive humidity sensors. Here, we introduce an innovative approach to humidity sensing technology by utilizing nanoresistance network-based built-in electric field drive strategy. The polyvinyl pyrrolidone/polyaniline nanofiber membrane (PPNFM), fabricated as a nanoresistance network material model, serves as the sensing layer that adsorbs water molecules and acts as charge carriers after dissociation. Moreover, the PPNFM generates a built-in electric field through the potential difference created by connecting to two electrodes. This built-in electric field drives the directional movement of dissociated positive and negative ions within the PPNFM, producing a voltage in response to humidity. The potential of PPNFM and its humidity response mechanism are systematically investigated and evaluated. Furthermore, the humidity sensing performance of the sensor can be optimized by adjusting the composition and size of the PPNFM. This approach eliminates the requirement for specific structures, streamlining the fabrication process and paving the way for the development of flexible, ultra-thin, and passive humidity sensors.