Role of Ni Do** on Bi₂O₄ Thin Films for Optical, Dielectric and Photocatalytic Applications

Abstract

Ni-doped bismuth oxide (Bi₂O₄:Ni) thin films with varying Ni concentrations of 1–5 wt.% were successfully fabricated by the dip-coating method. The monoclinic Bi₂O₄ phase of all thin films was confirmed by the XRD spectra. The average crystallite size of pure Bi₂O₄ was 45.98 nm, which was reduced to 39.23–33.39 nm after Ni do** (1–5 wt.%). It was revealed from SEM images that pure and Ni-doped bismuth oxide thin films showed an increase in grain size ranging from 11 nm to 21 nm. The band-gap value varied from 2.00 eV to 1.77 eV. The optical properties and crystallite size were correlated with each other. Among all Ni-doped Bi₂O₄, 2 wt.% Ni has very strong antibacterial activity against P. aeruginosa and S. aureus with a zone of inhibition of 30 ± 0.7 mm and 30 ± 2.12 mm, respectively. The effect of Ni do** on the photocatalytic activity of Bi₂O₄ thin films is reported. Prepared catalysis can play a very important role in the treatment of polluted air and water. The hop** mechanism justified the dielectric parameters which follow Koop’s theory and the Maxwell–Wagner model. The thin films have been to be found ferromagnetic. High-frequency devices find the low values of dielectric constants beneficial for them.