Lindqvist polyoxometalates as electrolytes in p-type dye sensitized solar cells

The development of new redox couples provides a clear strategy to improve power conversion efficiency (PCE) in p-type dye-sensitized solar cells (p-DSSCs) through enabling improvements in open-circuit voltage (V_OC). In this work we report the use of molybdenum and tungsten containing Lindqvist polyoxometalates (POMs), [TBA]₂Mo₆O₁₉ and [TBA]₂W₆O₁₉, as an alternative to the traditionally used I⁻/I₃⁻ redox mediator in p-DSSCs. POM electrolytes are cheap and easy to synthesize, air stable and transparent, making them suitable for tandem solar cell applications. Electrolytes were evaluated using a simple testing device to benchmark the respective devices. Up to a 5-fold increase in V_OC was observed for p-DSSCs employing electrolytes with POMs upon comparison with traditionally used I₃⁻/I⁻, while short-circuit photocurrents with the same order of magnitude were observed under identical dilute conditions.