Light trapping for solar cells using localised surface plasmons in self-assembled AG nanoparticles

Ag nanoparticle arrays, located on the front or rear surface of a Si solar cell, can provide effective lighttrapping via the excitation of localised surface plasmons. We identify key parameters in engineering random Ag nanoparticle arrays for optimum plasmonic light-trapping. We demonstrate that there is an asymmetry in scattering behaviour between particles located on the front and rear of a Si substrate, which we attribute to differences in the driving field at the position of the nanoparticles. Applying the design considerations presented, we report a relative photocurrent increase of 27% over the light trapping spectral region for thin c-Si solar cells incorporating a rearlocated self-assembled Ag nanoparticle array, constituting the largest reported enhancement due to plasmonic light trapping for such cells. Inclusion of a detached rear reflector behind these particles increases the photocurrent enhancement to 33%.