Efficiency enhancement of fluorescent concentrators with photonic structures and material combinations

This study examines concepts to increase the efficiency of fluorescent concentrator systems. Different system sizes and configurations are investigated in detail by external quantum efficiency measurements, light beam induced current maps and by IV-measurements. A photonic structure which serves as a bandstop reflection filter for the light emitted from the dyes in the fluorescent concentrator increases the system efficiency by 20% relative. Such photonic structures are especially beneficial for larger systems. The combination of two fluorescent concentrators made with different dyes in one stack increases system efficiency from 5.1% with only one dye to 6.7% for the stack.