Optical multiscale model for quantification of photon recycling including incoherent light scattering

Abstract

A comprehensive multiscale modeling framework for photon recycling in textured solar cells and LEDs is introduced, treating light absorption and emission on an equal footing under consideration of the full internal mode spectrum in the device. The framework seamlessly merges a coherent emission model, free from unphysical divergence and ensuring consistency with detailed balance principles, with an incoherent net-radiation model applied to optically thick layers. The scattering of light at nonplanar interfaces is taken into consideration through four characteristic mappings that depict the microscopic scattering process, which are calculated analytically or by using a Monte-Carlo ray-tracing method. The final output of the model consists of energy- and angle-resolved local emission, re-absorption, and energy flux rates for further coupling to electronic transport. To validate the model, it has been compared with analytical solutions for the re-absorption probability in an ideal semiconductor slab with either ideal Lambertian or flat surfaces. The comparison between analytical and numerical calculations shows excellent agreement.