Plasmonic light-trapping for Si solar cells using self-assembled, Ag nanoparticles

We present experimental results for photocurrent enhancements in thin c-Si solar cells due to light-trapping by self-assembled, random Ag nanoparticle arrays. The experimental geometry is chosen to maximise the enhancement provided by employing previously reported design considerations for plasmonic light-trapping. The particles are located on the rear of the cells, decoupling light-trapping and anti-reflection effects, and the scattering resonances of the particles are red-shifted to target spectral regions which are poorly absorbed in Si, by over-coating with TiO2. We report a relative increase in photocurrent of 10% for 22 mu m Si cells due to light-trapping. Incorporation of a detached mirror behind the nanoparticles increases the photocurrent enhancement to 13% and improves the external quantum efficiency by a factor of 5.6 for weakly absorbed light. Copyright (C) 2010 John Wiley & Sons, Ltd.