Polysaccharide-assisted crystallization of ZnO micro/nanostructures

• Polysaccharide-assisted crystallization method was used for the synthesis of ZnO micro/nanostructures with complex morphology (star, double-jellyfish, double-raspberry and edelweiss-flower).
• Three natural low-cost polysaccharides: sodium alginate, gum arabic and chitosan were used in order to change the shape of the ZnO crystallites.
• Both the structure (linear or branch) and the charge (anionic or cationic) of the polysaccharide play an important role in the morphological, structural and optical properties of the ZnO crystallites.

ZnO micro/nanostructures with complex morphology were synthesized by a simple chemical reaction between zinc nitrate and hexamethylenetetramine in the presence of polysaccharides. X-ray diffraction analysis showed that all obtained samples are of wurtzite structure. The reflectance and room temperature photoluminescence spectra have been used to investigate the optical properties of the ZnO structures. The scanning electron microscopy images reveal that the ZnO morphology (star, double-jellyfish, double-raspberry and edelweiss-flower) can be easily changed by varying the polysaccharides: sodium alginate, gum arabic and chitosan. The polysaccharide-assisted crystallization method could provide a facile approach to synthesize other desired compounds with controllable morphology.