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 self absorption 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 organic solar concentrators, a class of luminescent solar concentrators that exploit advances in thin film organic semiconductor technology and low cost manufacturing processes to create efficient, large area optical concentrators for inorganic solar cells. We report single and tandem waveguide organic solar concentrators with quantum efficiencies exceeding 50% and projected power efficiencies up to 6.8%. Near field energy transfer, solid state solvation, and phosphorescence are employed within a thin film organic coating on glass to substantially reduce self absorption losses, enabling flux gains exceeding F = 10, meaning that a photovoltaic cell attached to the concentrator generates approximately 10 × the power of the photovoltaic cell without optical concentration. Flux gains of F > 10 in organic solar concentrators should enable the economical use of high performance photovoltaic cells in low cost systems. We will conclude by examining key unsolved problems and the limits of the technology.

ANL Physics Division Colloquium Schedule