Researchers from the Nano/Bio Interface Center at The University of Pennsylvania - Parag Banerjee, David Conklin, Sanjini Nanayakkara, Tae-Hong Park, Michael J. Therien, and Dawn A. Bonnell - have announced results from their research on plasmonics, a new field in which surface plasmons are exploited to manipulate and control light. The research has shown that surface plasmons can be configured to induce electronic transport in molecular devices and in this manner convert optical energy into electrical conduction.

Hybrid nanostructures were fabricated in which 32nm gold particles are linked with optically active porphyrin molecules. The structures are designed such that the spacing between many of the particles is exactly the length that the molecules span.

The plasmons focus light to the junction and induce electrical conduction by localizing photon flux to increase exciton production in the molecule. The transport properties of the molecule, the proximity of the gold electrodes and the plasmons lead to current enhancements by factors of 4-20 (400 percent to 2,000 percent) even in these unoptimized devices.

These results suggest new strategies for energy efficient circuits, energy harvesting coatings, optical circuit components, and neural logic devices.