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

Abstract

The perovskite Ce_1-xK_xMoO₃, 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 Ce_1-xK_xMoO₃ 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 Ce_1-xK_xMoO₃. 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(E_F) values 1.07 10²³ eV⁻¹ cm⁻³, and a low relaxation time τ_rel≈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 Ce_1-xK_xMoO₃ to be too useful in the field of optoelectronics.