Effects of CE doping on the structural, optical and electrical properties of spinel SrCo 2 O 4 thin films

Cerium-doped strontium cobaltite spinel (SrCo₂O₄) thin films were synthesized using a sol–gel dip process and subsequently deposited onto glass substrates by a coating technique. The influence of Ce doping on structural, optical and electrical properties has been studied using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectrophotometry and impedance spectroscopy. The XRD analysis indicates that all samples exhibit a single-phase cubic spinel structure assigned to the Fd3 m space group, with the (311) plane emerging as the dominant orientation. IR spectra revealed the presence of vibrational modes associated to spinel SrCo 2 O 4. Deposited thin films show average transmittance above 80% in the visible range. The impedance measurements show that the equivalent circuit of the diagram of Ce doped SrCo 2 O 4 layers is an RpCp parallel. when the resistance Rp decreases while the capacitance Cp increases with Ce doping. Cerium incorporation alters the structural, optical, and electrical characteristics of SrCo₂O₄, leading to an increase in average crystallite size to 27.93 nm, a decrease in the optical band gap to 1.40 eV, a reduction in resistance to 33.06 Ω, and an enhancement in capacitance to 7.32 nF at a doping level of 5%.