Luminescent Solar Concentrators (LSCs) offer a means to reduce the cost of solar energy by concentrating incoming light. A LSC consists of a flat, transparent host matrix that is doped with fluorophores and has solar cells attached to its sides. Incident light is absorbed by the fluorophores and concentrated towards the sides of the host matrix via total internal reflection. LSCs are capable of absorbing diffuse sunlight which makes them very suitable for urban environments and building-integrated photovoltaics. Most commonly organic dye molecules are used as fluorophores; however, the absorption of dye molecules is spectrally quite narrow and therefore only a small part of the solar spectrum is harvested. The other two main mechanisms that limit the efficiency of LSCs are the non-unity quantum yield of the fluorophores and escape cone losses for light rays emitted at angles smaller than the critical angle. Both loss channels are aggravated by re-absorption of trapped photons. At the conference we will present various strategies developed in the photonic innovations lab at University College London to combat the aforementioned deficiencies. These include: i) alignment of fluorophores in the host matrix to improve light trapping, ii) conjugation of quantum dots with fluorescent dyes to widen the solar spectrum over which energy is being harvested from, while simultaneously minimizing re-absorption losses, and iii) plasmonic nanoparticles. We will also present recent developments in flexible LSCs and a novel experimental method developed by our group that enables researchers for the first time to separate out experimentally the different loss mechanisms.
© 2015 Optical Society of AmericaPDF Article