Morphology control and optical properties of Bi2O3 crystals prepared by low-temperature liquid phase method

γ-Bi 2 O 3 powders were prepared from [Bi(NO 3 ) 3 ·5H 2 O] and NaOH through low-temperature liquid phase method at <90°C. This process featured low cost, simplicity and a normal pressure. Bismuth oxides were synthesised in large quantities in water systems. Morphology, structure and optical properties were characterised by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet visible absorption spectrophotometry (UV–Vis). The SEM indicated that tetrahedral Bi 2 O 3 with the edge length of 1–5 μm was formed. The FTIR spectra show a chemical bond of Bi–O existed. Bi 2 O 3 presents the photo absorption properties from UV light region to visible light and the band gap of the Bi 2 O 3 is 3.0 eV.