Structural and physical properties of Ce1-xKxMoO3 for x = 0.0, 0.2, and 0.4 prepared by sol–gel method

The perovskite Ce1-xKxMoO3, where x = 0.0, 0.2, and 0.4, was prepared using sol–gel technique. Samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry DSC, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, impedance spectroscopy UV–VIS, diffuse reflectance spectroscopic, and photoluminescence (PL). Besides, the XRD and Raman spectroscopy revealed an orthorhombic phase with a Pnma space group for Ce1-xKxMoO3 samples. XPS analysis proved the existence of Mo3+ and Mo4+ ions. On the other hand, Raman spectroscopy has particularly shown the existence of the B1g mode associated to the MoO6 octahedron. And the DSC curves mark the absence of inflections which qualitatively shows the thermal stability of Ce1-xKxMoO3. Moreover, impedance spectroscopy confirmed that DC conductivity can be justified by the Arrhenius law at 475–600 K temperature range; the activation energy (≈0.314 eV) decreased with the potassium amount and by Mott’s VRH model for T < 445 K. In addition, the density’s greatest value of Fermi states, N(EF) values 1.07 1023 eV−1 cm−3, and a low relaxation time τrel≈0.5 μs were obtained with CKMO04 sample. In the end, the Tauc curves revealed that the bandgap decreased from 3.10 to 2.77 eV with K+ amount; the PL measurements exhibited intense emission of visible and near-infrared light under UV light excitation. In conclusion, all results found allow Ce1-xKxMoO3 to be too useful in the field of optoelectronics.