High Performance Porous Platinum Counter Electrodes for Co(II/III) Based Dye-Sensitized Solar Cells

Cobalt-based electrolytes have significantly advanced the tunability and performance of dye-sensitized solar cells (DSC). Although these electrolytes hold much promise to advance DSCs, there remain challenges in developing suitable electrocatalytic cathodes. Platinum is the most widely used catalyst in DSCs due to its long-term stability in harsh environments and ability to transfer charge to numerous electrolytes. Unfortunately, the Pt-Co^(II/III)BPY₃ redox couple is hampered by slow electron transfer kinetics. Here, we present a host-guest synthesis route based upon atomic layer deposition (ALD) to create a high surface area platinum electrode supported upon a conductive scaffold of niobium doped tin oxide (NTO). This approach maximizes the catalytic surface area of platinum while minimizing the inactive platinum atoms in the bulk. The resulting nanocomposites had tunable performance with low charge transfer resistances towards Co^(II/III)BPY₃ electrolytes that are used in dye-sensitized solar cells. The new electrode led to DSCs with enhanced fill factors and improved power conversion efficiencies (>11%) as compared to conventional platinum cathodes.