A Simple Cost-Effective Approach to Enhance Performance of Bifacial Dye-Sensitized Solar Cells

A simple cost-effective approach was demonstrated to increase the rear efficiency and ratio of rear-to-front efficiencies for bifacial dye-sensitized solar cells (DSCs). This was achieved by enhancing the transparency of the counter electrode of the DSC using a composite of platinum- and aluminum-doped zinc oxide (Pt/AZO). The thermally deposited composite Pt/AZO counter electrodes exhibited transmittance T550 nm = 0.70–0.74 versus Pt with 0.63. The comparable front power conversion efficiency (PCE
_front
) of fabricated DSCs using the composite Pt/AZO counter electrodes suggested that the presence of AZO in the composite had minimal effect on the catalytic activity of the platinum. DSCs with composite Pt/AZO counter electrode presented superior rear PCEs compared with platinum counterparts and was attributed to higher short-circuit current density
$J_{{\rm sc}}$
resulting from the larger transmittance of the composite counter electrode. The higher PCE
_rear
/
PCE
_front
of the composite-based DSCs compared with Pt-based DSC suggested that such transparent composite counter electrodes could be employed in bifacial DSCs.