The role of self-absorption in luminescent solar concentrators

Self-absorption or re-absorption of light by luminescent centers is a major loss mechanism in the luminescent solar concentrator (LSC). It leads to non-radiative energy losses governed by the luminescence quantum efficiency and radiative losses through escape cones. We have investigated the role of self-absorption in small (about 5cm x 5cm x 1mm) LSC samples containing nanorods. These samples were illuminated with a small laser spot, and position dependent measurements of the photocurrent and the emission spectrum were carried out. These measurements showed a rapid decrease in the LSC output with the distance of the illumination spot, which emphasizes the significance of self-absorption losses. A computational raytrace model was applied to simulate the experiment, and a good agreement with the experimental measurement was found.