High performance ultrathin silicon solar microcells enabled with nanophotonic light management and spectral upconversion

A type of integrated photovoltaic system that can improve the performance of ultrathin silicon solar cells is demonstrated by synergistically exploiting light trapping nanostructures and plasmonically enhanced spectral upconversion. Ultrathin (~8 μm) nanostructured silicon solar cells are embedded in a thin polymeric medium containing NaYF₄:Yb³⁺,Er³⁺ upconversion nanocrystals coated on a nanostructured silver substrate, where both excitation and emission processes of upconversion luminophores are considerably enhanced by the effects of local field amplification and far-field out-coupling via surface plasmon resonance. The photovoltaic performance of ultrathin nanostructured silicon solar cells on the nanostructured silver substrate with an upconversion medium is enhanced by ~130% compared to the bare silicon devices owing to the combined effects of nanophotonic light trapping and plasmonically enhanced spectral upconversion.