Controllable ZnO morphology via simple template-free solution route

Different morphologies of ZnO nanocrystals have been achieved controllably by agent-assisted chemical-liquid-deposition process. In this approach, no additional template materials or substrates are needed to obtain different morphologies in the reaction process. The rod-like ZnO nanocrystal has been synthesized by decomposing Zn(OH)42− directly in the solution. The slice-like and flower-like ZnO nanocrystals of hexagonal phase have also been obtained, respectively, using sodium citrate and ammonia as the structure directing agents. A very strong UV emission at ∼380 nm and green emission at ∼510 nm are observed in the photoluminescence (PL) spectra of the three kinds of ZnO nanocrystals. The possible formation mechanisms for synthesized ZnO nanocrystals with different morphologies have also been phenomenologically proposed.