  Photogalvanic solar cells, the original dye based solar cell, have yet to
fulfill their promise as a low fabrication cost, scalable energy conversion
system. The efficient performance of photogalvanic cells relies on high dye
solubility and selective electrodes with fast electron transfer kinetics. A new
configuration is proposed for the photogalvanic cells that removes these
impractical requirements. Instead of illuminating the device through the
electrode, as is the conventional approach, a new vertical configuration is
employed with light coming between the two electrodes. This way, the light
absorption and hence electron generation is spread through the depth of the
device. As a result, unreasonably fast electrode kinetics are no longer
required. The depth can be adjusted according to the concentration of the dyes,
and thus deeper cells enable low solubility dyes to be employed. The proposed
configuration is mathematically modeled and the advantages over the
conventional cell are shown. A numerical model is built for more detailed
analysis that gives practical guidelines for working towards device parameters
with high power conversion efficiency. The analysis suggests that upon the
realization of highly selective electrodes and an improved dye/mediator couple,
an efficiency of 13% should be achievable from the new configuration.
