Minimizing Energy Losses in Dye-Sensitized Solar Cells Using Coordination Compounds as Alternative Redox Mediators Coupled with Appropriate Organic Dyes

• Published in: Advanced energy materials 2012-06, Vol.2 (6), p.616-627
• Main Authors: Stergiopoulos, Thomas, Falaras, Polycarpos
• Format: Article
• Language: English
• Subjects: cobalt and copper complexes; dye-sensitized solar cells; Dyes; ferrocene; Ferrocenes; Iodides; Joining; organic dyes; Photovoltaic cells; redox couples; Regeneration; Roads; Solar cells; Solar energy
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201100781

To further boost the efficiency of dye‐sensitized solar cells, a correct evaluation of the real limitations of this type of solar cell should be conducted. From a simple analysis of the photovoltaic data found in the literature, it is evident that the Voc decrease, through energy losses, seems to be the most crucial factor diminishing the overall system efficiency. In particular, losses arising from the regeneration of the dye by the iodide/triiodide redox mediator are huge. The most convenient manner to recuperate these losses is the use of alternative redox mediators with more positive redox potentials than that of the iodide‐based shuttle. Among various types of redox active compounds, ferrocene/ferrocenium, Cu+/2+, and Co2+/3+ complexes are found to be the most effective in solar cells and the obtained efficiencies of more than 12% clearly show that a breakthrough is close, paving revolutionary roads towards making new records. This progress report focuses on the energy losses concerning dye regeneration by the iodide/triiodide redox couple in dye‐sensitized solar cells. These losses are mainly responsible for the decrease of photopotential and can be minimized using alternative innovative redox active mediators such as the ferrocene/ferrocenium, Cu+/2+, and Co2+/3+ complexes in combination with appropriate organic dyes.