Cobalt doping, etching, and attachment of gold nanoparticles and quantum dots on ZnO nanorods

Abstract

ZnO is an important material for optoelectronic applications such as solar cells and sensors due to its wide band gap and functional properties. Optimizing the growth mechanisms of ZnO nanorods as grown in a low temperature, wet chemical method will allow for an enhancement of material, optical, and electronic properties in a low cost production method. Our group fabricated nanorods on indium tin oxide (ITO) and glass substrates. The alignment and optical properties of the ZnO nanorods depend greatly on the initial seed layer of (doped) ZnO as well as the growth parameters. In this study we investigated the changes in the optical absorption properties of ZnO nanorods doped with cobalt. Cobalt doping was achieved by adding a percentage of cobalt chloride to the total volume of chemical bath precursor solution of Zinc nitrate and hexamethylentramine. Optical and energy dispersive X‐ray measurements reveal that the optical absorption of ZnO nanorods extends from 385 nm to 700 nm when doped with cobalt from 0.1 at.% to 9.7 at.%. In addition, we investigated the selective etching of ZnO with 3 molar concentrations of potassium chloride solution. Etching under 3 molar solution concentration produced ZnO nanotube structures that can be used for enhancing optical and chemical sensitivity. We also present absorption profiles of ZnO nanorods decorated with metallic nano particles of gold as well as CdSe quantum dots (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Systematic Study of the Structure–Property Relationships of Branched Hierarchical TiO2/ZnO Nanostructures

“…The general synthesis route for preparing branched hierarchical systems involves the following: (1) preparation of polymer solutions that contain the metal-oxide precursor, (2) electrospinning of the polymeric solution, (3) calcination of the electrospun nanofibers to generate metal-oxide structures by thermally removing the carrier polymer, and (4) hydrothermal growth of secondary branched nanorods on the metal-oxide nanofibers. The hydrothermal growth process requires two steps of seeding and growth treatments, which are performed in liquids, generally water, resulting in epitaxial and anisotropic crystal growth. − …”