Enhanced optical absorption in thin film solar cells by surface plasmons

We have investigated the influence of localized surface plasmon effects due to spherical metal nanoparticles on amorphous silicon based thin film solar cells. By far, silver is the most common metal used for surface plasmonics in solar cells. However, it would be of great interest, from a practical stand-point to find less expensive metals, such as copper, aluminum, titanium and their alloys. Using a two dimensional finite difference time domain method, we have simulated the surface plasmon effects due to a variety of metal nanoparticles and observed their optical properties. A noticeable conversion efficiency improvement due to the Ag and Cu nanoparticles was obtained.