Controlled synthesis and assembly of nanostructured ZnO Architectures by a solvothermal soft chemistry process

Controlled synthesis and organization of nanostructured materials using simple and low-cost methods is important in order to exploit their unique properties for practical applications. We describe the results of a systematic study of the solvothermal soft chemical synthesis of novel nanostructured ZnO architectures. Various ZnO nanostructured microspheres and microrod aggregates have been synthesized using Zn(CH3COO)(2)center dot 2H(2)O in ethylenediamine in the presence of HAuCl4-4H(2)O. In the absence of HAuCl4 center dot 4H(2)O, fibrous and coral-like ZnO rod aggregates are obtained. The morphologies and structures of the obtained ZnO architectures can be tuned by manipulating the relative amounts and the addition sequence of Zn(CH3COO)(2)center dot 2H(2)O and HAuCl4 center dot 4H(2)O. The Au(ethylenediamine)(2)(3+) complex, formed from Au3+ by combining with two ethyienediamine molecules, plays a key structure-directing role in controlling the morphology and structure of the obtained ZnO architectures. All of the nanostructured ZnO architectures can be indexed to the hexagonal wurtzite stricture, and they show variations in the optical absorption properties depending on the distribution and interaction of Art nanoparticles on the ZnO surface. The formation mechanism of the various nanostructured microspheres is also discussed.