Effect Of Annealing Conditions On The Struct-optical Properties Of ZnFe1.96La0.04O4 Nanoparticles

¹Department of Physics, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates

²Department of Physics, College of Engineering Guindy, Anna University, Chennai 600025, Tamilnadu, India

Adv. Mater. Lett., 2016, 7 (12), pp 971-978

DOI: 10.5185/amlett.2016.6387

Publication Date (Web): Oct 12, 2016

Copyright © IAAM-VBRI Press

E-mail:thols2006@gmail.com

Abstract

Lanthanum (La3+) ion doped zinc ferrite nanoparticles were synthesized by combustion method using glycine as fuel. The as-synthesized ZnFe_1.96La_0.04O₄ nanoparticles were subjected to annealing temperature of 900 oC for time intervals of 2 h, 6 h, 12 h, 24 h and 48 h. The as-synthesized and annealed ZnFe_1.96La_0.04O₄ nanoparticles were characterized as a single phase with normal spinel structure. The surface morphology of these nanoparticles were found to be non–uniform and agglomerated with fine pores/voids. The induced strain and dislocation density were reduced with increasing annealing time which enhanced crystallinity and increased grain size. The values of optical band gap calculated from UV/Vis/NIR spectra of the as-synthesized and annealed ZnFe_1.96La_0.04O₄  nanoparticles were found to decrease with increasing annealing time. They range from 2.48 to 2.19 eV from the simple method and 2.42–2.12 eV for direct and 1.87–1.71 eV for indirect from Kubelka–Munk function method. The optical band gap in ZnFe_1.96La_0.04O₄  nanoparticles can be tuned as function of varying annealing time and it seems to correlate with induced strains in the nano-crystallites. Therefore, the tuning of optical band gap with just changing the heating treatment of ZnFe_1.96La_0.04O₄  nanoparticles may make them suitable photocatalysis.

Keywords

Spinel, zinc ferrite nanoparticles, temperature, structural, optical.