Synthesis and characterization of plant ceramics doped tin oxide for humidity sensing application

The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be plant ceramics (PC) has been chosen as a dopant in the SnO₂ matrix inview of evaluating as a new sensor material. Different compositions of the precursors were prepared to optimize for achieving high humidity sensitivity. The synthesized materials were characterized for structural behaviour, vibrational functional groups, BET surface area, surface morphology and elemental analysis from X-ray diffraction, FT-IR spectra, N₂ adsorption/desorption isotherm at 77K, Scanning electron micrograph and Energy dispersive X-ray analysis respectively. The PC doped SnO₂ was evidenced from the X-ray diffraction spectra. Two probe DC-electrical resistance method at different humidity levels were used to determine the sensitivity values. Of the various compositions prepared, SnO₂-PC₂ showed comparatively higher humidity sensitivity (S_f) value, 4013 ± 265. A fast response and recovery time of 80s and 140s respectively was also achieved indicating the suitability of the PC doped SnO₂ as a good humidity sensor.