The synthesis of novel ZnO microcrystals through a simple solvothermal method and their optical properties

ZnO microcrystals with novel structures have been synthesized by a solvothermal method that is facile, low-cost and environment-friendly. Zn(NO3)2·6H2O is the only precursor and absolute ethanol is the solvent. By controlling the reaction time, temperature and molarity of zinc nitrate, ZnO entities with the shape of flower, nut, hexagon-pillar, popcorn, brush and sphere can be synthesized in high selectivity. The ZnO micronuts (length ∼8 μm and width ∼5 μm) are uniform in morphology, displaying an open gap on the surface that divides the body into two. The investigation on the optical properties of the ZnO microcrystals reveals that all the ZnO samples exhibit an excitonic absorption edge around 376 nm, and compared to bulk ZnO, there is a modest red shift of ∼6 nm that can be ascribed to size effect as well as the unique morphologies of the ZnO microcrystals.

Graphical abstractZnO micronut have been synthesized by a solvothermal method that is facile, low-cost and environmentally friendly. There is no need of any surface surfactant, and Zn(NO3)2·6H2O is the only precursor and absolute ethanol the solvent. Futhermore, this work will not only inspire rational preparation and assembly of other novel single crystalline nanostructures but also open up new opportunities for the development of environment-benign for prepare methods.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ In this paper, ZnO microcrystals have been synthesized in high selectivity by a solvothermal method. The ZnO micronuts (length ∼8 μm and width ∼5 μm) are uniform in morphology, displaying an opening gap on the surface that divides the body into two. ▶ The solvothermal method used in this paper is facile, low-cost, environmentally friendly, and Zn(NO3)2·6H2O is non-toxic and relatively cheap. There is no need of using any surface surfactant, and Zn(NO3)2·6H2O is the only precursor and absolute ethanol the solvent. The alcohol system is biosafe and environmentally benign. ▶ We find that the ZnO microcrystals are similar in excitonic absorption edge and PL properties. ▶ This work will not only inspire rational preparation and assembly of other novel single crystalline nanostructures but also open up new opportunities for the development of environment-benign for prepare methods. It is envisaged that the approach can be used to synthesize nanostructures of other oxides such as MgO and FeO.