Abstract
Single crystalline high quality α-Mn2O3 nanorods and sea-urchins assembled with pen-type nanoneedles have been successfully synthesized by template-free hydrothermal route. The variation in hydrothermal temperature has affected the morphology of the α-Mn2O3 sea-urchin assembled with the nanoneedles noticeably. The influence of temperature change on the thickness, crystallinity, surface morphology and optical properties of α-Mn2O3 has been characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), Raman Spectroscopy (RS) and UV-visible Spectroscopy. The results showed that in our experimental conditions, single crystalline nanorods of the α-Mn2O3 were obtained at a low temperature of 180 °C, while single crystalline sea-urchin assembled with pen-type nanoneedles were obtained by increasing the temperature to 280 °C. Nanorods and sea-urchin assembled with pen-type nanoneedles obtained had the well defined morphology and crystalline quality. The sea-urchin synthesized at 280 °C exhibited more than 90% absorption in UV-visible spectrum.