Study of Concentration and Temperature Dependent Structural, Optical, Photocatalytic and Antimicrobial Activity of MoO3 Thin Films by Ultra Spray Pyrolysis

Abstract

Molybdenum trioxide was used as a precursor for the deposition of thin films of varied concentrations onto the glass substrate by ultra-spray pyrolysis technique. Solutions of different concentrations viz. 0.05 M, 0.025 M, 0.0125 M were prepared and the substrate temperature varied to study the structural properties like XRD, UV-visible spectroscopy and FESEM of the MoO3 thin films. Being transition metal oxide molybdenum oxide (MoO3), exhibits fascinating chemical, structural, electrical and optical properties. The samples were prepared at different temperatures of 150, 250 and 350 ºC with the spray concentrations varying between 0.05 M, 0.025 M and 0.0125 M while the other spray operating parameters were fixed at their optimum values. X-ray diffraction technique was used to determine the crystalline size and nature of the films. For the substrate temperature 150 ºC, the films obtained are amorphous in nature while the films deposited at 250 and 350 ºC were found to be crystalline in nature giving α-MoO3 phase, which is evident from the X-ray diffraction pattern. The size of the crystal varied from 43 to 65 nm for the prepared samples. The band-gap energy by plotting Tauc plots was found to be in the range 2.51-3.01 eV. FESEM revealed two different types of morphological structures viz., spherical and nanorods. The photocatalytic activity of thin films obtained was estimated from their ability to degrade methylene blue (MB) under UV irradiation with excellent results. Antibacterial activity of thin films was checked against Pseudomonas aeruginosa for 1, 6, 10 and 96 h.