Effect of Calcination Temperature on the Structural, Thermodynamic, and Optical Properties of MoO3Nanoparticles

Temperature dependence of the structural, thermodynamic, and optical properties of MoO3nanoparticles synthesized using sol–gel and sonication methods were studied. MoO3nanoparticles showed variation in crystallite shape from hexagonal to orthorhombic and crystallite size in the range 3.05–5.21 nm with bandgap in the range 4.11–4.36 eV with change in the calcination temperature and the method of synthesis. Rietveld refinement of the X‐ray diffraction (XRD) data confirmed the crystallite phase transition with space group PE and Pbnmwith change in the lattice parameter ratio. Activation energy was calculated using XRD and TGA–DSC (thermogravimetry–differential thermal analysis) data and was found to be close to 4 kJ/mol. The bandgap fluctuation was due to the size dependence of the blue shift, which indicates strong quantum confinement due to the Bohr radius effect. Optical parameters such as the extinction coefficient, refractive index, optical conductivity, dielectric functions, and Urbach energy were calculated and found to depend on electron–phonon interactions. MoO3nanoparticles were synthesized using sol–gel and sonication methods. These nanoparticles showed variation in the crystallite shape from hexagonal to orthorhombic with the change in calcination temperature and the method of synthesis; also changes in the crystallite size and bandgap were observed. Their optical parameters such as the extinction coefficient, refractive index, optical conductivity, dielectric function, and Urbach energy were calculated and found to be dependent on electron–phonon interactions.