Converting light and heat into electricity using carbon based materials

  • Authors

    Dörling,1 A. B. El Basati,1 A. Gomez,1 M. Garriga,1 A. R. Goñi,1 M. Campoy-Quiles,1 M. S. Vezie,2 S. Few,2 I. Meager,2 H. Bronstein,2 R. S. Ashraf,2 I. McCulloch2 and J. Nelson,2 G. Pieridou3 and S. C. Hayes,3 J. D. Ryan,4 C. Müller,4 J. D. Craddock,5 J. E. Anthony,5 M. C. Weisenberger,5 A. Sorrentino,6 E. Pereiro6
  • Publication

    Exploring the origin of high optical absorption in conjugated polymers

    Nature Materials, 15, 746, 2016

    Photoinduced p- to n-type switching in thermoelectric polymer-carbon nanotube composites

    Advanced Materials, 28, 2782, 2016
  • Figure

    When light passes through a film of a polymer with curvature, it gets less absorbed than when it goes through a film of the same thickness but less curvature. As a result, polymers without curvature end up giving higher efficiencies in photovoltaic devices.

Light and heat are abundant renewable sources of energy that should be harvested in order to switch towards a more sustainable energy paradigm. Now mixtures of polymers and carbon allotropes (Bucky balls and nanotubes) are proposed as photovoltaic and thermoelectric technologies with strong potential for high efficiency which are simultaneously based on abundant and non-toxic materials.

In a large study published in Nature Materials [1], the group of Mariano Campoy-Quiles from ICMAB in collaboration with researchers at Imperial College London have discovered what makes a polymer a strong sun light absorber. They have carried out a combined theoretical and experimental investigation of more than 40 different materials in order to identify design rules for the absorption of polymer semiconductors. They found out that the strength of absorption is governed by the persistence length of the polymer, or in other words, the tendency of the polymer to attain a non-curved conformation. Using this simple criterion, the authors were able to theoretical screen materials for high absorption and, indeed, synthetized three polymers with about 40 % more absorption than conventional materials employed for organic photovoltaics. Interestingly, materials with increased persistence length can also lead to better electron transport. As a result of these two improvements, the corresponding solar cells can go from power conversion efficiencies of the order of 5 % all the way to 8 %.

The same group at ICMAB has also demonstrated the use of polymer based composites for harvesting waste heat. In a recent publication [2] they proposed using conductive fillers, such as carbon nanotubes, in combination with conjugated polymers in order to create composites that can behave as p-type or n-type thermoelectric materials depending on the stoichiometry. The use of UV light during the processing is demonstrated as a facile means of converting composites from p- to n-type, opening the possibility of simple patterning thermoelectric modules. A patent has been filled to protect these interesting results. The research in organic energy materials at ICMAB is framed within the ERC Consolidator Grant FOREMAT.   

1Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Spain
2Centre for Plastic Electronics and Imperial College London, UK
3Department of Chemistry, University of Cyprus, Cyprus
4Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Sweden
5Center for Applied Energy Research, University of Kentucky, USA
6ALBA Synchrotron Light Source, Spain

Institut de Ciència de Materials de Barcelona
Campus de la UAB 08193 Bellaterra, SPAIN

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