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 B-1g 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 (approximate to 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(E-F) values 1.07 10(23) eV(-1) cm(-3), and a low relaxation time tau(rel)approximate to 0.5 mu s 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.