High-efficiency dye-sensitized solar cells with ferrocene-based electrolytes

Dye-sensitized solar cells based on iodide/triiodide (i−/i3−) electrolytes are viable low-cost alternatives to conventional silicon solar cells. however, as well as providing record efficiencies of up to 12.0%, the use of i−/i3− in such solar cells also brings about certain limitations that stem from its corrosive nature and complex two-electron redox chemistry. alternative redox mediators have been investigated, but these generally fall well short of matching the performance of conventional i−/i3− electrolytes. here, we report energy conversion efficiencies of 7.5% (simulated sunlight, am1.5, 1,000 w m−2) for dye-sensitized solar cells combining the archetypal ferrocene/ferrocenium (fc/fc+) single-electron redox couple with a novel metal-free organic donor–acceptor sensitizer (carbz-pahtdtt). these fc/fc+-based devices exceed the efficiency achieved for devices prepared using i−/i3− electrolytes under comparable conditions, revealing the great potential of ferrocene-based electrolytes in future dye-sensitized solar cells applications. this improvement results from a more favourable matching of the redox potential of the ferrocene couple with that of the new donor–acceptor sensitizer.