Improved light absorption in thin-film silicon solar cells by integration of silver nanoparticles

Silver nanoparticles, produced by thermal evaporation and a subsequent annealing treatment, were integrated at the back side of thin-film silicon solar cells. Metallic nanoparticles can lead to (i) a strong enhancement of the electric field in their surrounding when they are irradiated by light and (ii) significant scattering of the light when they have the proper diameter (>100 nm). In this study, we investigated the optical properties of two types of substrates, one with large and well separated ellipsoidal silver nanoparticles (with average lateral size of 300 nm), and the other with silver nanostructures connected to each other. Furthermore, these substrates were used as back reflectors in microcrystalline silicon solar cells in substrate (n–i–p) configuration.