  Improving solar energy collection in aquatic environments would allow for
superior environmental monitoring and remote sensing, but the identification of
optimal photovoltaic technologies for such applications is challenging as
evaluation requires either field deployment or access to large water tanks.
Here, we present a simple bench-top characterization technique that does not
require direct access to water and therefore circumvents the need for field
testing during initial trials of development. Employing LEDs to simulate
underwater solar spectra at various depths, we compare Si and CdTe solar cells,
two commercially available technologies, with GaInP cells, a technology with a
wide band gap close to ideal for underwater solar harvesting. We use this
method to show that while Si cells outperform both CdTe and GaInP under
terrestrial AM1.5G solar irradiance, both CdTe and GaInP outperform Si at
depths > 2 m, with GaInP cells operating with underwater efficiencies exceeding
51%.
