Humidity Sensing Mechanism and Respiration Monitoring of WO3 Nanoplates with a Monoclinic Crystal Phase

摘要

Functioning of hydrothermally synthesized WO3 nanoplates was investigated for humidity sensing and respiration monitoring under different breathing conditions. The monoclinic phase was identified by the X-ray diffraction (XRD) technique. The average crystallite size was calculated by Williamson-Hall (W-H) plot (27 nm) and modified Scherrer equation (24 nm). The optical band gap was calculated as 2.7 eV using UV-visible spectroscopy. The field emission electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM) micrographs of readied WO3 have confirmed the formation of microstructured nanoplates having an average diameter of 216 nm. Fluorine-doped tin oxide (FTO) substrate was used for the deposition of film and also used as an electrode. The investigation of humidity was carried out at different relative humidity (RH) -11, 33, 44, 54, 74, and 95. The fabricated humidity sensor has shown excellent reversibility, stability and very small humidity hysteresis (<2) at room temperature. The maximum response was observed as 41.95 at 95 RH with response and recovery time as 2 s and 134 s respectively. During the 30 d of observation, only a 0.4 decrease in response was observed. The fabricated WO3-based humidity sensor was investigated for human respiration having respiration rates of 2.51 min(-1), 3.09 min(-1) and 3.74 min(-1). (c) 2023 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited. DOI: 10.1149/2162-8777/ acbf75