Growth of Dumbbell-like ZnO Microcrystals under Mild Conditions and their Photoluminescence Properties

• Published in: Inorganic chemistry 2007-07, Vol.46 (15), p.6204-6210
• Main Authors: Yu, Qingjiang, Yu, Cuiling, Yang, Haibin, Fu, Wuyou, Chang, Lianxia, Xu, Jing, Wei, Ronghui, Li, Hongdong, Zhu, Hongyang, Li, Minghui, Zou, Guangtian, Wang, Guorui, Shao, Changlu, Liu, Yichun
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic070008a

Large-scale uniform dumbbell-like ZnO microcrystals were successfully synthesized via a facile solution method under mild conditions. The as-prepared dumbbells, with lengths of 3.5−5.4 μm and diameters of 1.3−1.8 μm, possess a single-crystal hexagonal structure and grow along the [0001] direction. The influence of the reactant concentration on the size and shapes of the ZnO samples had been studied, and the results revealed that the reactant concentration plays a crucial role in determining final morphologies of the samples. Moreover, the evolution process of the dumbbell-like ZnO microcrystals was viewed by field-emission scanning electron microscopy (FE-SEM) characterization, and a possible formation mechanism was proposed. In addition, optical properties of the ZnO samples prepared at different reaction times were also investigated by photoluminescence (PL) spectroscopy. The room-temperature PL spectrum of the dumbbell-like ZnO microcrystals shows a strong UV emission peak. The UV emission is further identified to originate from the radiative free-exciton recombination by the temperature-dependent PL.