Influence of bismuth substitution on structural and optical properties of CuFe2-xBixO4 spinel structure

CuFe2-xBixO4 (x=0.0-2.0) spinel structures were synthesized using a sol-gel auto-combustion method. The effects of Bi3+ substitution on structural and optical properties were investigated using X-ray diffraction, Fourier-transformed infrared spectroscopy, and UV-Vis spectroscopy. A phase transition was observed in CuFe2-xBixO4 with increasing Bi content, leading to enhanced lattice parameters a and c due to Bi3+ larger ionic radius. As Bi substitution increased, the crystallite size decreased due to the reduced mobility and higher mass of Bi3+ ions. Controlled Bi substitution achieved the tunability of structural and optical properties, while local distortions from Bi3+ ions in the CuFe2O4 lattice increased the optical band gap energy. CuFe2-xBixO4 spinel structures show promise for applications in photocatalysis, gas sensors, pigments, and magnetic materials. We will clearly explain what we already know about Bi3+-substituted copper ferrite nanoparticles and stress how important it is to fully understand the changes in structure and optical properties that happen when Bi3+ is added.