Diameter-controlled synthesis of α-Mn2O3 nanorods and nanowires with enhanced surface morphology and optical properties.

Single crystalline α-Mn(2)O(3) nanorods, and nanowires with and without nanoparticles on them have been successfully synthesized by a template-free hydrothermal route. The variation in hydrothermal temperature has not only affected the diameter of the nanostructure but also noticeably affected the morphology and optical properties of the α-Mn(2)O(3) nanostructure. The influence of temperature on the diameter, crystallinity, surface morphology and optical properties of the α-Mn(2)O(3) nanostructure have been characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, transmission electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy and UV-visible spectroscopy and photoluminescent (PL) spectroscopy. The results showed in our experimental conditions that single crystalline nanorods of the α-Mn(2)O(3) were obtained at a temperature of 180 °C, while single crystalline nanowires were obtained by increasing the temperature to 240 and 300 °C. Nanowires with nanoparticles on them were obtained by increasing the temperature to 240 °C and nanowires without nanoparticles on them were obtained by increasing the temperature to 300 °C. The nanorods and nanowires obtained had a well-defined morphology. The nanowires synthesized at 300 °C exhibited an intense orange band PL spectrum.