Tuning the optical properties of Zn0.7Ni0.3Fe2-xPrxO4 (x=0.0, 0.1, and 0.2) for optoelectronics applications

Abstract

This study investigates the structural, morphological, and optical properties of Zn_0.7Ni_0.3Fe_2-xPr_xO₄ (x=0.0, 0.1, and 0.2) synthesized via the sol-gel auto-combustion method. X-ray diffraction (XRD) confirmed the formation of a cubic spinel structure (Fd3m) and revealed a systematic increase in lattice parameter (from 8.4144 Å to 8.4436 Å) with Pr³⁺ substitution, attributed to the larger ionic radius of Pr³⁺ compared to Fe³⁺. The crystallite size decreased with increasing Pr content, indicating inhibition of grain growth. Field emission scanning electron microscopy (FESEM) showed uniform, spherical nanoparticles with reduced agglomeration upon doping, while elemental mapping confirmed homogeneous distribution of Pr³⁺. UV-Vis spectroscopy demonstrated a red shift in absorption edges and a corresponding decrease in optical bandgap from 1.89 eV to 1.82 eV with Pr doping, due to the introduction of Pr 4f states and defect-induced band tailing. These findings highlight the tunability of structural and optical properties of Ni-Zn ferrites through Pr substitution, making them promising for visible-light photocatalytic and optoelectronic applications.