Impact of calcination temperature on structural and optical properties of erbium-doped zinc ferrite nanoparticles.

Erbium-doped zinc ferrite nanoparticles (ZnFe1.9Er0.1O4) were prepared by the sol–gel auto-combustion method. In order to study the impact of calcination temperature, the prepared powder was divided into four parts and calcinated at 700, 900, 1100 and 1300°C. XRD confirmed the formation of a spinel structure with a single phase and Fd3m space group. Crystallite size increased from 19.45 to 30.22 nm with the increase in calcination temperature. SEM images showed agglomerated flakes having voids and pores on the surface. The average grain size increased from 157.76 to 237 nm with the increase in calcination temperature. FTIR showed two fundamental absorption bands related to octahedral and tetrahedral sites along with other three absorption bands in the frequency range 400–4000 cm−1. The optical energy bandgap was increased from 3.8166 to 4.2779 eV with the increase of calcination temperature. Hence, it is concluded that the optical energy bandgap can be tuned with the calcination temperature. [ABSTRACT FROM AUTHOR]