State Laboratory of Surface and Interface Science and Technology, Zhengzhou University of Light Industry , Zhengzhou 450002, China.
ACS Nano. 2013 Dec 23;7(12):10482-91. doi: 10.1021/nn404591z. Epub 2013 Nov 25.
ZnO twin-spheres topologically exposed in ±(001) polar facets have been successfully produced on a large scale. The fragmentary and hexagonal ±(001) facets of ZnO tilt and assemble gradually for 8-12 generations to form supercrystals. The surfactant effect on the formation of ZnO supercrystals reveals that their structure stepwise evolves from prisms to dumbbells to twin-spheres exposed in ±(001) facets and eventually to twin-spheres covered with dots. A hollow ring around a prism, which connects two hemispheres of the supercrystals, is finally sealed inside each of the twin-spheres. Based on the experimental observations, a stepwise self-assembly mechanism is proposed to understand the formation of the supercrystals. It is also observed that the ZnO twin-spheres exhibit anisotropic blue emission in intensity attributed to their special surfaces exposed in ±(001) facets. Novel devices could be designed and fabricated through carefully tailoring the microstructure of ZnO supercrystals.
在大规模制备方面，成功地制备出了在 ±(001) 极面拓扑暴露的 ZnO 孪球。ZnO 的不完整和六边形 ±(001) 面逐渐倾斜和组装，经过 8-12 代形成了超晶体。表面活性剂对 ZnO 超晶体形成的影响表明，其结构逐步从棱柱体演变为哑铃体再到在 ±(001) 面暴露的孪球体，最终形成带有点的孪球体。棱柱体周围的一个空心环连接着两个超晶体的半球，最终在每个孪球体内部封闭。基于实验观察，提出了一个逐步自组装的机制来理解超晶体的形成。还观察到 ZnO 孪球表现出各向异性的蓝色发射强度，这归因于其在 ±(001) 面暴露的特殊表面。通过仔细调整 ZnO 超晶体的微结构，可以设计和制造新型器件。
