Self-assembly and enhanced optical absorption of Bi2WO6 nests via ionic liquid-assisted hydrothermal method

Bi2WO6 uniform hierarchical nest-like structures have been successfully synthesized through an ionic liquid-assisted hydrothermal method in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4). The Bi2WO6 hierarchical structures have an average diameter of about 3–5 μm and are assembled by Bi2WO6 nanosheets with size ranging from 16 to 20 nm. The results show that ionic liquid [Bmim]BF4 is vital for the formation of Bi2WO6 nest-like hierarchical structures. The UV–vis diffuse reflectance spectroscopy indicate that Bi2WO6 hierarchical nest-like structures induce a significantly enhanced optical absorbance in the UV–vis region, which is ascribed to multiple scattering within the hierarchical assemblies to the lengthened optical path length for light transporting.