Synthesis and characterization of silver oxide nanoparticles prepared by chemical bath deposition for NH3 gas sensing applications

Abstract

Nano-silver oxide thin films with high sensitivity for NH3 gas were deposited on glass substrates by the chemical bath deposition technique. The preparations were made under different values of pH and deposition time at 70ᵒ C, using silver nitrate AgNO3 and triethanolamine. XRD analysis showed that all thin films were polycrystalline with several peaks of silver oxides such as Ag2O, AgO and Ag3O4, with an average crystallite size that ranged between 31.7 nm and 45.8 nm, depending on the deposition parameters. Atomic force microscope (AFM) technique illustrated that the films were homogenous with different surface roughness and the grain size ranged between 55.69 nm and 86.23 nm. The UV-Vis spectrophotometer showed that the optical direct energy gap ranged between 1.66 eV to 2.12 eV. The silver oxide thin film gives a high sensitivity of 70.12 for NH3 gas at 75°C operating temperature. This study shows that different types of silver oxides can be prepared by the CBD techniques, with the nanostructure to be used in gas sensors and optoelectronic applications.