In this study, chemical solution-grown ZnO (CS-ZnO) nanomaterials were prepared via a benign, ultrasonicated low-temperature solution immersion route. The humidity sensor was constructed using CS-ZnO nanomaterials by a simple brush printing technique. This research aimed to explore the humidity sensing attributes and investigate their correlation to surface, structural, and chemical association. The structural (i.e., crystallinity, morphology, and phonon characteristics), and surface characteristics exhibited in the CS-ZnO nanomaterials were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM with EDS), Raman spectroscopy, X-ray photoelectron spectrometer (XPS) and reflection electron energy-loss spectroscopy (REELS). The humidity sensor utilizing CS-ZnO nanomaterials exhibited acceptable resistance changes along with an adequate sensor resistance ratio and sensitivity of 33.89 ± 2.25 and 4.95 ± 0.11 MΩ/%RH, respectively. The sensor demonstrated a maximum sensing response of 97.08 ± 0.11 and reliable repeatability behaviour within the relative humidity range of 40 to 90 % RH. The preparation of the CS-ZnO as a sensing material provides a unique direction for designing a cost-effective and highly sensitive humidity monitoring sensor.
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