Efficient charge generation by relaxed charge-transfer states at organic interfaces.

Autor: Vandewal K; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Albrecht S; Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany., Hoke ET; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Graham KR; 1] Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA [2] King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia., Widmer J; Institut für Angewandte Photophysik TU Dresden, George-Bähr-Strasse 1, 01062, Dresden, Germany., Douglas JD; Department of Chemistry, University of California, 727 Latimer Hall, Berkeley, California 94720, USA., Schubert M; Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany., Mateker WR; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Bloking JT; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Burkhard GF; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Sellinger A; 1] Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA [2]., Fréchet JM; 1] King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia [2] Department of Chemistry, University of California, 727 Latimer Hall, Berkeley, California 94720, USA., Amassian A; King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia., Riede MK; 1] Institut für Angewandte Photophysik TU Dresden, George-Bähr-Strasse 1, 01062, Dresden, Germany [2]., McGehee MD; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA., Neher D; Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany., Salleo A; Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA.
Jazyk: angličtina
Zdroj: Nature materials [Nat Mater] 2014 Jan; Vol. 13 (1), pp. 63-8. Date of Electronic Publication: 2013 Nov 17.
DOI: 10.1038/nmat3807
Abstrakt: Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.
Databáze: MEDLINE