Silicon Quantum Dot-Poly(methyl methacrylate) Nanocomposites with Reduced Light Scattering for Luminescent Solar Concentrators

Silicon quantum dots with indirect bandgap photoluminescence are promising luminophores for large-area luminescent solar concentrators (LSCs). However, if commercially viable devices are to be achieved, silicon quantum dots must be dispersed within functional, light-guiding matrices such as acrylic slabs without losing their high photoluminescent quantum yield or succumbing to light-scattering agglomeration. With a goal of limiting scattering and producing functional LSC materials, we study silicon quantum dot/poly(methyl methacrylate) (PMMA) bulk polymerized composites. Ray-tracing Monte Carlo modeling predicts that scattering losses are significant for large-area silicon quantum dot LSCs unless the characteristic scattering length is at least as large as the LSC side length. We compare the effect of particle ligand choice on the nanocomposites, using particle loadings ranging from 0.06 to 0.50 wt %. We find that methyl 10-undecenoate functionalized silicon quantum dots in PMMA composites exhibit low levels of particle agglomeration, and thus light scattering, as compared to analogous silicon quantum dots capped with 1-dodecene. As a result, these ester-Si/PMMA composites show an improvement in light guiding compared to the alkane-Si composites, which is beneficial for future LSC applications.