The role of Förster Resonance Energy Transfer in luminescent solar concentrator efficiency and color tunability

Förster-type resonance energy transfer (FRET) is demonstrated in a luminescent solar concentrator (LSC) material containing two air-stable, high quantum yield laser dyes in a PMMA matrix. The concentration regime surrounding the Förster critical distance is determined for the system. Two-dye LSC films employing FRET are shown to increase the absorption of air mass 1.5 solar irradiance without affecting the self absorption properties of the film. The impact of nonradiative transfer efficiency on LSC performance is experimentally demonstrated and evidence is presented suggesting higher concentration two-dye films are have reduced waveguide transport losses under excitation of the shorter wavelength dye when compared to less concentrated films of the same optical density. The impact of FRET efficiency and thus LSC film fluorescence spectra on LSC color determination is investigated and shown to be minimal. LSC color determination is shown to be accurate through the use of standard subtractive color schemes that consider only film absorption, and wide color tunability is shown to be achievable through the use of a subtractive color model, with as few as three appropriately absorbing dyes