High-temperature-mixing hydrothermal synthesis of ZnO nanocrystals with wide growth window

High-quality and controllable growth of nanocrystals (NCs) have been attracting great attention. Here, a high-temperature-mixing hydrothermal (HTMH) method was designed to synthesize ZnO NCs with high crystallinity and narrow size distribution in a wide growth window. Compared with conventional hydrothermal (CH) growth, zinc source and alkali precursors were intentionally separated in temperature-rising stage and permitted to mix at the starting of heat preservation stage of HTMH growth. Highly crystalline ZnO NCs with uniform spherical morphology can be formed at alkali concentration and temperature windows as wide as 0.1–0.5 M and 160–200 °C, respectively. However, the products via CH method have much larger changes in not only morphology but also size. These results demonstrated that the high-temperature-mixing reaction greatly facilitates nucleation but depresses grain growth. Considering the simplicity and reproducibility, such HTMH method could have wide potentials for the fabrication of various functional nanocrystals.

Graphical abstractA high-temperature-mixing hydrothermal (HTMH) method was designed to prepare uniform ZnO NCs in a wide-growth-window with alkali concentration and temperature windows as wide as 0.1–0.5 M and 160–200 °C. The heating-up process induced overlap of nucleation and growth can be effectively enhanced by such method, which can have an important influence on the ZnO morphology. Combining the simplicity and reproducibility, such HTMH method can be extended and used in the preparation of various nanocrystals for solution-processed devices.Figure optionsDownload full-size imageDownload as PowerPoint slide