Dr Kylie Catchpole seminar, "Light trapping for enabling new solar cell designs"

ANU node researcher Dr Kylie Catchpole presented a seminar at UNSW about her group's work on "Light trapping for enabling new solar cell designs".

Abstract:

Light trapping is of fundamental importance in many types of solar cells to allow maximum efficiencies, and hence lowest costs, to be reached. We show that that light trapping can lead to substantial efficiency increases using rear surface scattering, near-field enhancement and for tandem solar cells. A doubling of the photocurrent due to light trapping is demonstrated by the combination of silver nanoparticles with a highly reflective back scatterer on the rear of a silicon thin film solar cell. We also propose a planar ultra-thin absorber concept exploiting plasmonic resonance absorption enhancement. We calculate a maximum absorption of 90% for TM polarized normally incident light in a 5 nm thin-film absorber with a single-pass absorption of only 1.7%. Broadband and wide-angle absorption is demonstrated.

Tandem solar cells based on crystalline silicon present a practical route toward low-cost cells with efficiencies above 30%. We evaluate inorganic thin-film top cells in a tandem stack with a high-efficiency c-Si bottom cell. We show when light trapping is incorporated, even relatively low quality earth-abundant semiconductor materials with luminescence efficiencies of 10-5 and diffusion lengths below 100nm are compatible with tandem cell efficiencies above 30%.