Heat induced nanoforms of Zinc oxide quantum dots and their characterization

In our studies we observed heat induced phase transitions of Zinc oxide quantum dots at 60, 200, 360 and 400$^\circ$C, where all the transitions were irreversible except the transition at 60$^\circ$C which was a reversible one. The phase transition at 60$^\circ$C indicated a heat induced conformational change which was supported here by studying polarizing micrographs of ZnO quantum dots thin film. The X-ray diffraction studies of the sample fired at different temperatures as indicated by the thermal analysis were performed in order to understand the changes occurred due to transitions. The study also indicated a new and simple approach to develop ZnO nanorods by just thermal decomposition of the ZnO quantum dots firing in furnace at 200$^\circ$C with 2 h soaking. In order to have a proper insight of the structural changes we performed scanning electron microscopy. Optical characterization was done by UV-vis and fluorescence spectrophotometer.