Proceedings of 6th International Conference on Hybrid and Organic Photovoltaics (HOPV14)
Publication date: 1st March 2014
We have focused on aliphatic polymers bearing redox-active groups per repeating unit. The redox polymers are characterized by an ultimate population of the electron-releasing and -gaining site that allows efficient redox-driven electron or charge transport throughout the polymer layer via self-exchange reactions. The electrochemical reaction-based charge-transfer is one of the key reactions in a mediation system of DSSCs. We have been trying to apply these charge-transporting materials to DSSCs to replace the conventional acetonitrile solution of iodide redox couple with the purpose of improving the conversion efficiency and/or (quasi) solidify the cells. Solid-type DSSC fabricated with highly redox-active nitroxide radical polymers achieved 9% efficiency. The voltage, short circuit current density, and fill factor were related with (kinetic) reactivity and (thermodynamic) redox potential of the radical polymers; for example, efficient charge-separation yielded significantly high voltage of 1.0 V. We demonstrated the cell with radical polymer-based rechargeable electrodes, which is being tested as a cord-less power source assisted with interior lighting.
Acknowledgement
This work was supported by Grants-in-Aid for Scientific Research (No. 24225003) from MEXT, Japan, NEDO project (No. P07015), and the FIRST Program on “Development of Organic Photovoltaics toward a Low-Carbon Society” from JSPS, Japan.
Schematic image of a charge-storageable DSSC composed of redox polymer-based rechargeable electrodes, and the chemical structures for the redox polymers.
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