Silver nanoparticles have been fabricated on glass and silicon substrates, and silicon solar cells, by evaporation of 10 nm layers followed by thermal annealing. Distinct localized surface plasmon resonances are observed in the optical spectra of the annealed samples, and these strongly affect the cell reflectance and spectral response, both positively and negatively. At short wave lengths photocurrent is improved due to forward-scattering by quadrupolar modes, while at longer wavelengths photocurrent is deteriorated due to back-scattering by dipolar modes. Back-scattering is attributed to modification of the angular scattering distribution of the nanoparticles by the silicon substrate. (C) 2009 Elsevier B.V. All rights reserved.