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.
Fahr
Stephan
S
Institut für Festkörpertheorie und -optik, Max-Wien-Platz 1, 07743 Jena, Germany. stephan.fahr@uni-jena.de
Ulbrich
Carolin
C
Kirchartz
Thomas
T
Rau
Uwe
U
Rockstuhl
Carsten
C
Lederer
Falk
F
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