Nanoparticles and Efficiency Enhancement in Plasmonic Solar Cells

In this study, the effect of various nanoparticles with different sizes, shapes and densities on the photocurrent of plasmonic solar cells was investigated. Nanospheres and nanocubes of Ag and Au were synthesized by polyol and seed-mediated method to serve as plasmonic scattering centers. Special immobilization treatments of the surface of GaAs based solar cells were performed to achieve the control over the densities of the particles. The photocurrents of the plasmonic solar cells with varying densities and shapes of Ag and Au nanoparticles were measured, respectively. While the immobilization of the Ag particles on GaAs surface can be well controlled, it proved difficult for Au particles. The highest efficiency enhancement was achieved for Ag nanospheres with a surface coverage of about 11%. If the density of Ag nanoparticles is too large, clusters are formed which lead to additional enhancement at longer wavelengths, however the overall photocurrent enhancement is lowered due to absorption of light in the particles.