Hierarchical construction of ZnO architectures promoted by heterogeneous nucleation

In this work, ZnO hierarchical architectures are successfully fabricated by concentration-controlled heterogeneous nucleation behavior through a one-pot solution method, free of organic structure-directing agents or pretreated substrates. A two-stage nucleation-growth process should account for the assembly process. First, the ZnO flowerlike plate aggregates formed with fast nucleation-growth kinetics. Then, these plate aggregates served as substrates to induce secondary heterogeneous nucleations under appropriate supersaturation degree. Ostwald-ripening assisted oriented attachment was believed to play a key role in the growth behavior. It provides an approach for the construction of hierarchical architectures with the advantage of precluding alien species. Raman scattering and room-temperature photoluminescence studies showed high consistency with respect to the crystallization improvement at elevated temperatures, which further showed that optical methods possess great potential in probing the microstructure of ZnO crystals.