Integrating GaAs, Si, and Dye-Sensitized Solar Cells in Multijunction Devices and Probing Harsh Condition Behavior

Mechanically stacked single illuminated area sequential series multijunction dye-sensitized solar cells (SSM-DSCs) were fabricated with varying bottom devices including DSC, silicon (Si), and gallium arsenide (GaAs). The use of near-infrared (>750 nm) photons for conversion into electricity is probed for each of the three technologies. The effect of using these photons on multijunction device power conversion efficiencies is investigated with a three-subcell SSM-DSC design where the top and middle subcells were DSC devices with D35 and B11 sensitizers, respectively. The power conversion efficiencies were found to follow the order: DSC/DSC/GaAs > DSC/DSC/DSC > DSC/DSC/Si. Low-light conditions were examined for the third subcell technologies as independent solar cells to understand the effects of receiving low light intensity as part of a multijunction system. GaAs and DSC as bottom devices both demonstrated a superior response under filtered or reduced illumination to that of Si in these studies. The influence of harsh temperatures on DSC device performance was also examined.