Quantifying Mie Scattering in Luminescent Solar Concentrators for Improved Performance

Abstract

Luminescent solar concentrators (LSCs) are waveguiding devices that collect solar light to supplement photovoltaic devices. Scattering in waveguides is critical to the LSC performance, but it is challenging to quantify its contribution, severely hindering the development of LSCs. In this work, we developed an analytical approach to quantify the Mie scattering coefficient (αs) and anisotropy factor (g) in LSCs. By using the αs and g, we conduct theoretical calculation and Monte Carlo ray-tracing simulation to estimate the optical properties and optical efficiency of LSCs based on Gd1.5Y1.5Al5O12:Ce3+ phosphors. In all cases, both the calculated and simulated results agree well with the experimental observations, evidencing the feasibility of this approach. According to our model, scattering in the waveguide improves LSC performance by rerouting incident photons propagation to the edges but degrades LSC performance by redirecting radiated photons into the escape cone. We demonstrate that the enhancement of scattering increases both the scattering gain and loss as well as improves the absorption of LSCs. Finally, an external quantum efficiency (η ext) of 4.2% for a 20 × 20 cm2 LSC is achieved by optimizing the scattering. This work provides quantitative guidelines for estimating the scattering in LSCs, which will guide future research on LSC designs.