Influence of Surfactant Micelles on Morphology and Photoluminescence of Zinc Oxide Nanorods Prepared by One-Step Chemical Synthesis in Aqueous Solution

Abstract

Single-crystalline ZnO nanorods with different morphologies of radial-shaped needles and single needle were prepared by one-step chemical synthesis in aqueous solutions with and without the surfactant sodium dodecyl sulfate (SDS). The ZnO nanorods prepared in the SDS solution have narrower average width, smaller aspect ratio, and wider optical band gap of about 3.36 eV compared with those prepared in water. In both cases, ZnO nanorods exhibit visible photoluminescence by various lattice defects. These results indicate that a confinement of growing ZnO crystals by spherical micelles leads to more uniform growth, and thus the ZnO nanorods in the SDS solution have narrower average width and more uniform morphology than those in water. It is suggested that a band gap narrowing does not occur for ZnO nanorods in SDS solution because dodecyl sulfate ions effectively passivate lattice defects of neutral oxygen vacancies which produce shallow donor levels.