Cobalt-doped zinc oxide nanoparticles synthesis by a fast polymer precursor based method

Full text: Zinc oxide is a versatile semiconductor material and have shown many applications as UV detector, piezoelectric devices, photocatalysis, photovoltaic devices and gas sensors. Furthermore, ZnO nanoparticles have shown an antibacterial activity, enhancing this property when doped with Cobalt. Moreover, room temperature ferromagnetism is observed for a nanosized ZnO doped with many transitions metals, such as Mn, Ni and Co. In the present work, nanostructured Co doped-ZnO was synthesized by a modified fast polymeric precursor method based on soluble polymer. This method involved a water-based complexation of Zn and Co, with concentration from 0.1 to 5.0%-mol of cobalt, by water soluble polyacrylate. The solution was dried and calcined by 120 minutes at 400, 450, 500 and 550 °C. The temperatures or thermal decomposition were determined using Differential Scanning Calorimetry (DSC). A Fourier-Transform Infra- Red Spectroscopy (FTIR) was proceeded to determine the structure of calcined product. X-Ray Diffraction was performed at LNLS (XRD1 beamline), showing very crystalline pattern, specially the powders thermally decomposed at 550 °C. Using Scherrer inference calculated from diffractogram peaks, nanoparticles under 50 nm are present. Scanning Electron Microscopy was also employed to study the morphology of the particles. This process yielded the synthesis of nanoparticles in very short time of about six hours, faster than conventional polymeric precursor methods as Pechini and sol-gel, and no ageing step was needed. (author)