Controllable, surfactant-free growth of 2D, scroll-like tellurium nanocrystals via a modified polyol process

In this study, we demonstrate that single crystalline tellurium with a 2D, scroll-like structure that deviates from the intrinsic linear crystallographic nature can be controllably synthesized via a modified polyol process by the reduction of tellurium nitrate (Te-N-O) in refluxing ethylene glycol, where no growth modifier such as surfactants or templates is involved. In the preparation, the kinetic control of the 2D growth is primarily manipulated by modulating the Te-N-O concentration in the solution. The morphology depends on the how the reactant is added. Stepwise addition of the reactant Te-N-O is crucial for the formation of the scroll-like morphology. It is demonstrated that ID tubular products with sharp tips rather than 2D structures are achieved when Te-N-O with equal quantity is injected in one step. Lowering the reaction temperature is favorable to the shape perfection of the nanotubes. On the basis of the characterizations, we propose the formation mechanism of this unique 2D structure to be an asymmetric growth process and subsequent epitaxial evolution. As the first report about 2D tellurium nanostructure, this strategy is attractive for enhancing the comprehension about the growth behavior of tellurium nanocrystals in solution system, which is helpful for the following property investigation and potential applications in nanotechnology.