Pathways to a brighter luminescent solar concentrator

This thesis represents a collection of theoretical, modeling, experimental and fabrication work to advance the field of luminescent solar concentrators (LSCs). First, a novel experimental method is proposed to separate the optical efficiency and the most dominant loss channels in LSCs, escape cone and non-unity quantum yield losses. It is the first method to determine all three LSC metrics which is a step forward from existing methods that calculate solely the optical efficiency. I developed a hybrid model that couples the finite-difference time-domain and Monte-Carlo ray tracing to simulate various systems that involve nanostructures. Among other systems, the method was used to determine the potential of plasmonic LSCs. It is shown that metallic absorption causes substantial optical losses which limits the applicability of plasmonics for LSCs. Next, fluorophore alignment and Förster resonance energy transfer (FRET) is investigated theoretically and experimentally. Ray tracing is again the method of choice to simulate a LSC with aligned and linked fluorophores. Homeotropic alignment improves the trapping efficiency while the linking induces FRET between the fluorophores to circumvent the reduced absorption of homeotropic alignment. As shown in this thesis, the efficiency of a LSC can be strongly enhanced by both, alignment and FRET; also, the quantum yield of the donor in the FRET pair is not as vital due to the efficiency of FRET. This makes quantum dots very suitable as donors due to their spectrally wide absorption. As a proof-of-concept I fabricated a LSC with quantum dots linked to organic dye molecules. The optical efficiency of the LSC is strongly enhanced due to reduced non-unity quantum yield losses. In my final project, I fabricated flexible LSCs made of polydimethylsiloxane to increase the potential applications of LSCs. Crucially, the LSC device remains efficient when bent.