Gallium ion-assisted room temperature synthesis of small-diameter ZnO nanorods

Abstract

We report a method for synthesizing small-diameter ZnO nanorods at room temperature (20°C), under normal atmospheric pressure (1atm), and using a relatively short reaction time (1h) by adding gallium salts to the reaction solution. The ZnO nanorods were, on average, 92nm in length and 9nm in diameter and were single crystalline in nature. Quantitative analyses revealed that gallium atoms were not incorporated into the synthesized nanocrystals. On the basis of the experimental results, we propose a mechanism for the formation of small-diameter ZnO nanorods in the presence of gallium ions. The optical properties were probed by UV–Vis diffuse reflectance spectroscopy. The absorption band of the small-diameter ZnO nanorods was blue-shifted relative to the absorption band of the ∼230nm diameter ZnO nanorods (control samples). Control experiments demonstrated that the absence of metal ion-containing precipitants (except ZnO) at room temperature is essential, and that the ZnO nanorod diameter distributions were narrow for the stirred reaction solution and broad when prepared without stirring.