Various morphologies of cobalt hydroxides have been successfully prepared from cobalt nitrate with the assistance of dimethylglyoxime in water/ethanol solutions by hydrothermal processing at 220 °C. The crystalline products are hexagonal phase of β-cobalt hydroxide, and the crystallinity increases as the volume ratio of water to ethanol rises. Hexagonal plate-like, broom-like or straw bundle-like, and grass-like cobalt hydroxides are obtained with water to ethanol ratios of 1:0, 2:1 and 1:2, respectively. The novel bundle-like assemblies are further constructed from lots of nanobelts, which mainly grow along [100] direction and evolve from less-crystalline disc-like structures and semi-crystalline flower-like assemblies as the hydrothermal time extended.

One-dimensional (1D) 8-hydroxyquinoline metal complex nanomaterials exhibit distinctive characteristics that differ from those of their bulk counterparts. Owing to their small size, shape anisotropy, unique structures, and novel properties, these organometallic 1D nanostructures are promising candidates for various devices. This review highlights current progress in the synthesis of 1D 8-hydroxyquinoline metal complex nanomaterials and summarizes their optoelectronic properties and applications. The mainly synthetic strategies are divided into three categories, which include vapor phase growth, solution phase growth, and self-assembly. Special attention is paid to the formation mechanisms and the control measures for 1D nanostructured 8-hydroxyquinoline metal complexes. Other new methods such as template-based synthesis and electrospinning are briefly described. Merits and shortcomings of each synthetic strategy are simply discussed. Then, a variety of optoelectronic properties including luminescence, field emission, charge transport, photoconductivity, and photo-switching properties are reviewed, and their applications in optoelectronic devices, field emission, and templates are also surveyed. In the end, concise conclusions are provided, and personal perspectives on future investigations of 1D 8-hydroxyquinoline metal complex nanomaterials are proposed.