Optical, Structural and Morphological Properties of Photocatalytic ZnO Thin Films Deposited by Pray Pyrolysis Technique

Abstract

Photocatalytic ZnO thin films have been deposited onto glass substrate by spray pyrolysis technique. The sprayed solution consists of 0.1 M of zinc acetate dihydrate dissolved in double distilled water and sprays onto ultrasonically cleaned glass substrates maintained at 350˚C, through an air-atomizing nozzle. The X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX and UV-VIS spectrophotometer were applied to describe the structural, morphological, compositional and optical properties of ZnO catalyst. XRD analysis confirms that the films were found to be single phase hexagonal wurtzite structure. The SEM micrograph of the films is shown highly uniform, crack free and found to be fiber like structures. The optical transmittance spectra of the ZnO thin films were found to be transparent to visible light and the average optical transmittance was greater than 85%. The direct optical band gap energy values of the films shift towards the lower energy as a consequence of the thermal annealing. The Urbach energy of the films was found to increase with annealing temperature. The refractive index of the films was calculated and the refractive index dispersion curve of the films obeys the single oscillator model. The values of oscillatory energy E o , dispersion energy E d , and static dielectric constant ε s for the ZnO thin films were determined. The films were evaluated for their ability to degrade methylene blue. The Langmuir-Hinshelwood kinetic model was used to interpret quantitatively the observed kinetic experimental result. The photocatalytic activity of ZnO thin films was enhanced by annealing temperature.

Investigation of dispersion parameters, dielectric properties and opto–electrical parameters of ZnO thin film grown by ALD

“…It , s found that, the two obtained Eg values are in a good agreement with each other within the experimental error. Our average value of Eg is supported with previously reported results of other researches for ZnO films prepared by different methods [37,[44][45][46][47][48][49][50] as seen in Table 2.…”

Structural, Morphological, Optical, Luminescent and Magnetic Properties of Nanostructured ZnO Thin Film

“…And this trend in band gap may be due to the appearance of band tail from defects and surface roughness [28]. The decrease in the optical band gap as the function of annealing temperature is associated with the interatomic distance [45]. The observed band gap value is in good agreement with the earlier reports [46,47].…”

Sb doping influence on structural properties of ZnO thin films

“…It can see from the figure that nanofiber structure formed in pure and 1% Sb doped ZnO. Komaraiah et al also observed similar structures using SEM images of spray pyrolysis technique for ZnO thin films [25]. When the Sb concentration attained 2 and 3%, it is clear to see the nanofiber structure disappears with the increase of doping ratio, which may be attributed to the influence of structural change resulting from replacing Zn 2+ atoms with Sb 3+ atoms.…”