Wet Chemical Synthesis Optimisation and Characterisation of Nano Holmium Oxide for Photocatalytic and Dielectric Device Applications

Holmium oxide nanoparticles were synthesized by the wet chemical method, a simple cost-effective chemical route. The effect of calcination on the structure, size, optical and electrical properties was studied in detail. Particle size was measured via X-ray diffraction and field emission scanning electron microscopy and analyzed using the Scherrer equation and the Williamson–Hall plot, agrees very well confirming the quality of the synthesis route adopted. Calcination increases the particle size and the crystalline quality. Absorption in the ultraviolet region was observed for all samples, and a decrease in the bandgap upon calcination was registered and explained. A large dielectric constant was observed for the calcinated sample indicating its profuse use as a dielectric material. Ferroelectric polarization-electric field hysteresis loop shows an increased loop area upon calcination meaning a better charge accommodation ability. Under ultraviolet light irradiation, the holmium oxide nanoparticles showed photocatalytic degradation of methylene blue.