Angular response of dye solar cells to solar and spectrally resolved light

The power conversion efficiency (eta) of a dye solar cell (DSC) with a 13 mu m thick TiO2 layer increases with solar AM1.5 light's angle of incidence by 10% at 55 degrees +/- 5 degrees and then decreases at higher angles due to Fresnel reflection at the front air/glass interface. For cells with thin TiO2 (3 mu m), the enhancement in eta is substantially larger (16%). We show, also through spectral quantum efficiency measurements, that the angular enhancement for thin cells is mainly due to optical path lengthening, quantifying the relevant parameters useful for photon management strategies and for understanding the productivity of DSC modules outdoors. (C) 2011 American Institute of Physics. [doi:10.1063/1.3663973]