Enhanced light trapping in thin-film solar cells by a directionally selective filter.
A directionally selective multilayer filter is applied to a hydrogenated amorphous silicon solar cell to improve the light trapping. The filter prevents non-absorbed long-wavelength photons from leaving the cell under oblique angles leading to an enhancement of the total optical path length for weakly absorbed light within the device by a factor of kappa(r) = 3.5. Parasitic absorption in the contact layers limits the effective path length improvement for the photovoltaic quantum efficiency to a factor of kappa(EQE) = 1.5. The total short-circuit current density increases by DeltaJ(sc) = 0.2 mAcm(-2) due to the directional selectivity of the Bragg-like filter.
Ulbrich
Carolin
C
IEF5-Photovoltaik, Forschungszentrum Jülich, 52425 Jülich, Germany. c.ulbrich@fz-juelich.de
Peters
Marius
M
Bläsi
Benedikt
B
Kirchartz
Thomas
T
Gerber
Andreas
A
Rau
Uwe
U