Catalytic interplay and oxygen vacancy mediation on pristine and silver doped bismuth vanadate thin films for potential ammonia detection at room temperature

Revolutionized modern industries have evolved to develop tremendously potential chemi-resistive gas sensors to
safeguard human health, prevent food spoilage, and improve air quality. Binary metal oxide semiconductors hold
significant promise as a sensing layer in chemi-resistive gas sensors but fall short in terms of real-time flexibility,including cross-selectivity, lower operating temperature, and limit of detection. To overcome these hindrances, ternary metal oxide spine as sensing layers have garnered significant attention due to their superior physico
chemical properties, dual cationic nature, and different valence states, etc. This work presents the deposition of
pristine and silver-doped bismuth vanadate thin films using the facile chemical spray pyrolysis method. As
deposited thin films were scrutinized through powder X-ray diffraction, UV–Vis spectroscopy, Raman spectros
copy, atomic force microscopy, morphological analysis, and finally their gas sensing performances were evalu
ated. A higher dislocated network (9.1 ×10 4), narrowed bandgap (2.71 eV), increased surface roughness (1127
nm), enhanced oxygen vacancies (32.20 %), and smaller crystallite size (32.99 nm) facilitated enhanced gas
molecule diffusion on the 5 wt.% Ag-doped BiVO4 (BVA5’s) film. Among various volatile organic compounds,
ammonia (NH3) is molecularly smaller in size, the presence of lone pairs of electrons in nitrogen atoms, and the
catalytic effect through silver doping contribute to a high sensor response (S =Igas/Iair =159 @ 1 ppm) at room
temperature (~30 ◦C and RH =~52 %), demonstrating its potential for ammonia gas sensing devices.