Introduction
© 2006 Wiley
Solar cells and photo-detectors operate under the same basic process: converting light into current. Miniature versions of these devices will rely on nanostructured materials with good photoconducting properties. Although the figures of merit for inorganic photoconducting nanowires, such as ZnO or Si, have been measured, relatively little is known about the properties of organic nanowires.
Given that organic nanowires could be both chemically tunable and relatively inexpensive to integrate into electronic circuits, Gareth Redmond's group at the Tyndall National Institute in Cork, Ireland has measured photoconductivity in a single polymer nanowire1. The authors fabricated the 200-nm-wide, 15-
m-long polymer wires using a simple template wetting technique. Metal contacts were made on either end of a single wire to measure the photo-induced current over several on–off cycles of a near-ultraviolet laser.
The wires' quantum efficiency — the number of current-carrying electrons produced per photon hitting the wire — is about 0.1%, which is competitive with several inorganic nanowires. As in many polymer-based electronic devices, the limiting factors may be the non-crystalline structure and poor electrical contact with the metal leads.