A kinetic rate model of novel upconversion nanostructures for high-efficiency photovoltaics

We present a computational model for predicting the net solar energy conversion efficiency of a single-junction solar cell backed by a solid-state photon upconversion nanostructure. We model the upconversion process using a series of kinetic rate equations to calculate equilibrium populations. We determine the upconversion quantum efficiency (UQE) of the proposed device as a function of intentionally introduced photon energy sacrifice (PES). Combining this result with the detailed balance method for estimating solar cell efficiency, we are able to optimize the nanostructure design to achieve as high as 39% net solar conversion efficiency for a GaAs host cell.