Quantifying Mie Scattering in Luminescent Solar Concentrators for Improved Performance

Luminescent solar concentrators (LSCs) are waveguidingdevicesthat collect solar light to supplement photovoltaic devices. Scatteringin waveguides is critical to the LSC performance, but it is challengingto quantify its contribution, severely hindering the development ofLSCs. In this work, we developed an analytical approach to quantifythe Mie scattering coefficient (& alpha;(s)) and anisotropyfactor (g) in LSCs. By using the & alpha;(s) and g, we conduct theoretical calculation and MonteCarlo ray-tracing simulation to estimate the optical properties andoptical efficiency of LSCs based on Gd1.5Y1.5Al5O12:Ce3+ phosphors. In all cases,both the calculated and simulated results agree well with the experimentalobservations, evidencing the feasibility of this approach. Accordingto our model, scattering in the waveguide improves LSC performanceby rerouting incident photons propagation to the edges but degradesLSC performance by redirecting radiated photons into the escape cone.We demonstrate that the enhancement of scattering increases both thescattering gain and loss as well as improves the absorption of LSCs.Finally, an external quantum efficiency (& eta; (ext)) of 4.2% for a 20 x 20 cm(2) LSC is achievedby optimizing the scattering. This work provides quantitative guidelinesfor estimating the scattering in LSCs, which will guide future researchon LSC designs.