Luminescent Solar Concentrators
C.L. Mulder, P.D. Reusswig, C. Rotschild and M.A. Baldo
Department of Electrical Engineering and Computer Science,
Massachusetts Institute of Technology,
Cambridge, Massachusetts 02139, USA
It has long been recognized that luminescent solar concentrators (LSCs) are perhaps the ideal solar concentrator for photovoltaic cells. LSCs are expected to be inexpensive to manufacture and can generate theoretically unlimited optical concentrations without the need to track the sun. But losses within LSCs have proved difficult to overcome. In this talk, we will address recent developments in photovoltaic cells and LSC technology that prompt a renewed examination of this technology. In particular, we will discuss: (i) the development of infrared LSCs; (ii) LSCs that employ aligned dye molecules for better coupling to solar cells; and (iii) organic solar concentrators, a class of luminescent solar concentrators that exploit advances in thin film organic semiconductor technology to substantially reduce self absorption losses, enabling flux gains exceeding F = 10, meaning that a photovoltaic cell attached to the concentrator generates approximately 10 x the power of the photovoltaic cell without optical concentration. Finally, we will discuss third generation LSCs. We will describe our recent work on exciton fission and also the performance of optical multijunctions that use multiple LSCs to separate the solar spectrum for different solar cells. We will conclude by examining key unsolved problems and the limits of the technology.