The article investigates the use of localized surface plasmons on silver nanoparticles to enhance the absorbance of silicon solar cells, particularly thin-film and wafer-based structures. The authors found that surface plasmons can significantly increase the spectral response of thin-film cells over the entire solar spectrum, with a notable enhancement near the band gap of silicon. For wafer-based cells, a sevenfold enhancement was observed at λ=1200 nm and up to 16-fold enhancement at λ=1050 nm for 1.25 μm thin silicon-on-insulator (SOI) cells. The results are compared with a theoretical dipole-waveguide model, and the effect of varying particle size on the enhancement is also reported. Additionally, the article discusses the enhancement in electroluminescence from ultrathin SOI light-emitting diodes and the potential of surface plasmons for improving the efficiency of both thin-film and wafer-based solar cells. The method is promising for reducing the thickness of silicon cells and enhancing light trapping without degrading electrical characteristics.The article investigates the use of localized surface plasmons on silver nanoparticles to enhance the absorbance of silicon solar cells, particularly thin-film and wafer-based structures. The authors found that surface plasmons can significantly increase the spectral response of thin-film cells over the entire solar spectrum, with a notable enhancement near the band gap of silicon. For wafer-based cells, a sevenfold enhancement was observed at λ=1200 nm and up to 16-fold enhancement at λ=1050 nm for 1.25 μm thin silicon-on-insulator (SOI) cells. The results are compared with a theoretical dipole-waveguide model, and the effect of varying particle size on the enhancement is also reported. Additionally, the article discusses the enhancement in electroluminescence from ultrathin SOI light-emitting diodes and the potential of surface plasmons for improving the efficiency of both thin-film and wafer-based solar cells. The method is promising for reducing the thickness of silicon cells and enhancing light trapping without degrading electrical characteristics.