Effects of annealing temperature on structural properties of Cs doped molybdenum HPOM nanoparticles prepared by hydrothermal method

Abstract

Thin films of nanocrystalline Cs doped molybdenum heteropolyoxometalate (HPOM) have been deposited on glass substrate using hydrothermal technique. The different preparative parameters like concentration of bath, deposition time, bath temperature, PH of the bath have been optimized in order to get good quality thin films of Cs doped molybdenum heteropolyoxometalate. The deposited films were annealed at 100°C, 150°C and 200°C. These annealed thin films were characterized by using SEM, EDS, XRD and TGA-DTA techniques for their structural properties. SEM results showed that, after doping Cs in phospomolybdic acid spherical grains are formed which are uniformly distributed over the surface of the substrate. EDS study for the sample deposited showed that presence of P, Mo, O and Cs in the film without any major impurity. XRD pattern of annealed thin films shows better crystanality of Cs doped molybdenum heteropolyoxometalate (HPOM) material having simple cubic spinel structure. Various structural parameters such as crystallite size, dislocation density and microstrain have been calculated and they are found temperature dependent. After increasing temperature crystallite size of Cs doped molybdenum heteropolyoxometalate (HPOM) material increases and dislocation density and microstrain decreases. The TGA-DTA study showed that, Cs doped molybdenum heteropolyoxometalate material is thermally stable up to 687.61°C.