Structural, compositional and textural properties of monoclinic α-Bi₂O₃ nanocrystals

Perfect α-Bi2O3 nanocrystals were successfully synthesized via green synthesis method. X-ray diffraction studies clearly revealed a single phase α-Bi2O3 nanocrystal without any secondary phase. The strong XPS peaks observed at 160 and 165 eV were assigned to Bi4f5/2 and Bi4f7/2 and clearly revealed Bi(3+) valence states of bismuth ions. Photoluminescence spectra revealed the perfect α-Bi2O3 crystal nature without having inter band transitions between defects, impurity and different valence states of bismuth ions. Out of thirty expected modes, the symmetry assignments of Raman bands correlated to Bg(4), Ag(5), Bg(5), Bg(6), Ag(7), Ag(8), Ag(9), Ag(10), Ag(12) and Ag(14) modes revealed perfect α-Bi2O3 nanocrystals. Transmission electron microscopy studies combined with a selected area electron diffraction pattern recorded on α-Bi2O3 nanocrystals show monoclinic structure preferential orientation with sizes approximately 200 nm in diameters and 500 nm in length.