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 µm 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 © 2010 John Wiley & Sons, Ltd.