New luminescent materials and filters for Luminescent Solar Concentrators

In a Luminescent Solar Concentrator (LSC), short-wavelength light is converted by a luminescent material into long-wavelength light, which is guided towards a photovoltaic cell. In principle, an LSC allows for high concentration, but in practice this is prevented by loss mechanisms like limited sunlight absorption, limited quantum efficiency and high self absorption. To tackle these problems, a suitable luminescent material is needed. Another important loss mechanism is the escape of luminescent radiation into directions that do not stay inside the light guide. To reduce this amount, wavelength-selective filters can be applied that reflect the luminescent radiation back into the light guide while transmitting the incident sunlight. In this paper, we discuss experiments and simulations of new luminescent and filter materials. We will introduce a phosphor with close-to-optimal luminescent properties. A problem for use in an LSC is the large scattering of this material; we will discuss possible solutions for this. Furthermore, we will discuss the use of broad-band cholesteric filters in combination with this phosphor.