Abstract :
Stacked multijunction (tandem) solar cells have been prepared by mechanically stacking dye-sensitised solar cells (DSCs) and a GaAs/
AlXGa(1 X)As graded solar cell (GGC) as the top and bottom cells, respectively. Three organic dyes with different absorption spectra
(D131, D102 and D205) were used in the DSCs, in order to match the photocurrent density between the DSC and the GGC. Tuning
the absorption range of the DSC by choosing an appropriate dye, increased the overall photovoltaic conversion efficiency due to the
optimal utilisation of the solar spectrum in the individual cells. The open circuit photovoltages (VOC) of the GGC and the DSC with
D131 were 1.11 V and 0.76 V, respectively, resulting in a VOC of 1.85 V and a photovoltaic conversion efficiency of 7.63% for the tandem
cell. Although the overall conversion efficiency has not exceeded that of the GGC (7.66%), these tandem cells provide adequate VOC
values for water splitting applications.
2011 Elsevier Ltd. All rights reserved
