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Cost-Effective Replacement for Iodide in Dye-Sensitized Solar Cells

Colorado State University

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Electron Transfer Mediator Summary

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Cross-section of solar cell
Cross-section of solar cell

Technology Marketing SummaryDye-sensitized solar cells (DSSCs) are used to create electrical energy from sunlight. The cell has three components: the cathode, the photoanode, and the electron transfer medium (ETM). The ETM commonly contains iodide salts and other components. Current forms of DSSCs are noted for their durability and cost effectiveness; however, the volatile and corrosive nature of the salts used in the cell limit the materials that can be used to construct the cell. For example, the cathode material is limited to expensive metals such as titanium and platinum, instead of cheaper metals like gold, copper, aluminum, or nickel. Cell leakage is also a problem because of the corrosive effects of the salts, and can lead to failure of the DSSC. The problems of cell leakage and limited construction materials associated with iodide salt DSSCs need to be resolved.DescriptionResearchers working at Colorado State University and the University of Ferrara have created a new metal complex-based ETM that overcomes the problems of traditional DSSCs. The new ETM has been demonstrated to be 80 percent as efficient as traditional iodide salt mediums in otherwise identical cells. Furthermore, the new ETM is less corrosive than traditional iodide ETMs. It is also more transparent than iodide-based mediums.


This new metal-based electron transfer technology reduces the compatibility issues between the cell material and the ETM: cell leakage issues can be decreased, and new structural materials, once considered incompatible with the ETM, can also be used to construct the cell. Additionally, cheaper metals can be used as the cathode, reducing the cost of the cell. The new ETM allows for the possibility of more transparent cells that could be configured differently, possibly stacked, to increase power output. The possibility even exists of creating a polymer from the new ETM that could be used to create a solid-state device.

  • Potentially cheaper than other forms of photovoltaic energy production
  • Non-corrosive and non-volatile
  • Enables alternative cell configurations
  • Wider range of cell construction materials possible
  • Longer product life than iodide solar cells
Applications and Industries
  • Photovoltaic solar energy using dye-sensitized solar cells
  • Suitable for both outdoor and indoor/low light applications
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 7,019,138
Metal complex-based electron-transfer mediators in dye-sensitized solar cells
This present invention provides a metal-ligand complex and methods for using and preparing the same. In particular, the metal-ligand complex of the present invention is of the formula: L.sub.a-M-X.sub.b where L, M, X, a, and b are those define herein. The metal-ligand complexes of the present invention are useful in a variety of applications including as electron-transfer mediators in dye-sensitized solar cells and related photoelectrochromic devices.
Colorado State University 03/28/2006
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
02-012Prototype - Successful laboratory prototype; awaitng further deelopmentAvailable - Available for exclusive or non-exclusive licensing03/28/201207/13/2012

Contact CSU About This Technology

To: Jeremy Nelson<>