Effects of Ce doping on the structural, optical and electrical properties of spinel SrCo2O4 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 Fd3m 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%.