Cooperative self-construction and enhanced optical absorption of nanoplates-assembled hierarchical Bi2WO6 flowers

Bi2WO6 hierarchical multilayered flower-like assemblies are fabricated on a large scale by a simple, hydrothermal method in the presence of polymeric poly(sodium 4-styrenesulfonate). Such 3D Bi2WO6 assemblies are constructed from orderly arranged 2D layers, which are further composed of a large number of interconnected nanoplates with a mean side length of ca. 50nm. The bimodal mesopores associated with such hierarchical assembly exhibit peak mesopore size of ca. 4nm for the voids within a layer, and peak mesopore size of ca. 40 nm corresponding to the interspaces between stacked layers, respectively. The formation process is discussed on the basis of the results of time-dependent experiments, which support a novel 'coupled cooperative assembly and localized ripening' formation mechanism. More interestingly, we have noticed that the collective effect related to such hierarchical assembly induces a significantly enhanced optical absorbance in the UV-visible region. This work may shed some light on the design of complex architectures and exploitation of their potential applications. (C) 2008 Elsevier Inc. All rights reserved.