Light trapping by a dielectric nanoparticle back reflector in film silicon solar cells

Drop-coated high-refractive-index nanoparticles used as a back reflector for thin-film solar cells are non-absorbing Mie-scatterers that enhance light trapping. We present optical measurements and theory for this approach. A 40% enhancement of the photocurrent and efficiency of a 2.5 μm thick single-crystal Si solar cell on display glass is achieved by adding a back reflector of 270 nm rutile TiO2 nanoparticles.