Series-Connection Designs for Dye Solar Cell Modules

We present a vis-a-vis experimental and PSPICE circuital comparison and optimization of W- and Z-type dye solar cell (DSC) modules. Important design and technological aspects which can, at the same time, promote and hamper each scheme were identified, including differing photocurrents (by a factor 1.6) between front- and back-illuminated cells, sheet-resistance-induced halving of fill factor (FF) when increasing cell width (2-20 mm), and vertical connections with resistances that can affect FF. The modules fabricated showed efficiencies of 4.7% and 4.2% over active area for Z and W modules and 3.4% over total area for both (due to different aperture ratios). Our simulations showed that geometrically optimized front-illuminated DSC Z modules would yield higher efficiencies than W modules built with the same materials if ideal vertical connections can be achieved. Pointers for further differing optimization of each scheme are laid out.