A novel nanocomposite device, which consists of liquid crystals and semiconductor nanorods, has been designed and fabricated. It reveals a very unique and useful behavior in that the polarization of the emission from semiconductor nanorods can be controlled by an external bias. The large magnitude of polarization anisotropy of 0.63 can be quantitatively interpreted very well in terms of the dielectric contrast between semiconductor and liquid crystal. Our approach is quite general, which is applicable to other nanomaterials, and it utilizes the currently mature liquid crystal display technology. The results open up new possible applications for one-dimensional semiconductor nanostructures in smart optoelectronic applications, including optical switches, integrated photonic devices, as well as electrochromatic gadgets in the near future.

In the absence of an external direction-controlling process, exclusive self-bundled arrays of CdS nanorods are formed using a facile solution-based method involving trioctylphosphine (TOP) and tetradecylphosphonic acids (TDPA) as cosurfactants. CdS self-bundled arrays with an area of as large as 2.0 microm(2) could be obtained. A detailed mechanistic investigation leads us to conclude that the matching in nanorod concentration, intrinsic properties of CdS, and the hydrocarbon chains of the surfactants between adjacent CdS rods play key roles in the self-assembly. In sharp contrast to the defect dominant emission in solutions, the self-bundled CdS nanorods exhibit optical emission nearly free from the defect-states, demonstrating their potential for applications in luminescence and photovoltaic devices.

No abstract

No abstract