ZnO Nanostructures: From a Single Nanowire to Solar Cells

Abstract

In this article, surface and interface properties of 1-D ZnO nanostrutcures from the fundamental optical properties of a single ZnO nanorod to the application in photovoltaics will be presented. In the first part, optical and vibrational properties of a single ZnO nanorod will be investigated by cathodoluminescence (CL) and photoluminescence (PL) spectroscopy and confocal Raman spectroscopy. The anomalous energy shift in the emission spectra of individual nanorods with sizes beyond the quantum confinement regime was observed, which is mainly due to the enhanced surface effect in nanostructures (1). In addition, the interplay between the local phonon behavior and geometric anisotropy was revealed by Raman mapping images of an individual nanorod (2). In the second part, the optoelectronic properties at the interfaces between ZnO nanorods and conjugated polymer will be addressed, which represents the potential application in photovoltaics and photodetectors. Through interfacial nanostructuring, the photovoltaic performance can be largely improved due to the enhanced efficiency in charge separation and transport (3,4) at interfaces.