Dissolution−Recrystallization Induced Hierarchical Structure in ZnO: Bunched Roselike and Core−Shell-like Particles

Zn(OH) 2 /ZnO nanohybrid particles were fabricated by the dissolution−recrystallization route in hot distilled water. Hierarchical structured ZnO particles were easily obtained by the further dehydration reaction without morphology deformation. X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy clarified the formation mechansim. Thermodynamically less stable polar planes (0001) of ZnO rods tended to dissolve quickly; the thermodynamically stable Zn(OH) 2 first grows on ZnO surfaces by heterogeneous nucleation to minimize their surface energy. The morphologies, bunched roselike and core−shell-like structures, are controllable by adjusting the immersion period. Further dissolution−recrystallization resulted in the formation of core−shell morphology. As-fabricated hierarchical structured products will have potential applications in optoelectronic devices such as dye-sensitive solar cells and gas sensor due to its high porous structure and strongly adsorption property.