Rugate filter for light-trapping in solar cells.
We suggest a design for a coating that could be applied on top of any solar cell having at least one diffusing surface. This coating acts as an angle and wavelength selective filter, which increases the average path length and absorptance at long wavelengths without altering the solar cell performance at short wavelengths. The filter design is based on a continuous variation of the refractive index in order to minimize undesired reflection losses. Numerical procedures are used to optimize the filter for a 10 microm thick monocrystalline silicon solar cell, which lifts the efficiency above the Auger limit for unconcentrated illumination. The feasibility to fabricate such filters is also discussed, considering a finite available refractive index range.
Institut für Festkörpertheorie und -optik, Max-Wien-Platz 1, 07743 Jena, Germany. stephan.fahr@uni-jena.de
Stephan
S
Fahr
Carolin
C
Ulbrich
Thomas
T
Kirchartz
Uwe
U
Rau
Carsten
C
Rockstuhl
Falk
F
Lederer
D003198:Computer Simulation; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation*; D008027:Light; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000295:instrumentation*; D012542:Scattering, Radiation; D012993:Solar Energy