Another idea which could improve the efficiency of solar cells is to exploit the phenomenon of plasmonics, where the free electrons at the surface of a metal are displaced when an incident electric field is present, i.e. light is incident on the metal. The most common use of plasmonics is in the form of localised surface plasmon resonances which occur in particles a few nanometers in diameter. At a certain frequency, a peak in the reflection spectrum exists, which is dependent on the size and shape of the nanoparticle. A local enhancement in electric field is also observed, which allows light to be transferred into waveguiding modes into the substrate.

Optical Images of Chirality

Plasmonic Image

Nanoparticles of gold or silver can be fabricated either by e-beam lithography and a lift-off technique, evaporation of a deposited thin film, or deposition of a colloidal solution. All three techniques are being researched in the group.

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