Analysis of the optical, chemical, surface, and humidity sensing characteristics of nanostructured Bi2O3-doped MoO3 materials

Abstract

In the present investigation, we report characterization and humidity parameters of pure molybdenum trioxide & 10 wt% Bi2O3-doped MoO3 nanocomposite fabricated by a solid-state reaction method. Pellet samples of Bi2O3-MoO3 nanocrystalline powders with pure and 10 wt% of Bi2O3 in MoO3 were prepared. The X-ray diffraction studies showed the peak of orthorhombic molybdite and monoclinic bismite present in the sample. The crystallite size was measured using the Scherrer formula and found to be in the range of 37–57 nm. The grain size of samples was measured by FE-SEM micrographs. FE-SEM micrographs suggest that small crystallites agglomerate to form large grains. The FT-IR results confirm the chemical bonding of molybdenum and bismuth with oxygen. FT-IR spectroscopy was used to investigate the molecular vibration and functional groups of synthesized nanomaterials. The optical band gap was determined by UV–vis spectroscopy and found in the range of 4.08 to 4.11 eV. The surface topography was studied by AFM. The synthesized samples were exposed to moisture in the range of 10–90 % RH. It was discovered that an increase in the weight percentage of Bi2O3 in MoO3 causes the sensor's sensitivity to rising. The sample with 10 wt% exhibits the highest sensitivity, 16.41 MΩ/%RH. The hysteresis slightly decreases with increasing wt.% of Bi2O3 in MoO3 and exhibits 2.21 % for a sample with 10 wt%.