Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 90: Poster III

HL 90.31: Poster

Donnerstag, 10. März 2016, 16:00–19:00, Poster A

Revealing spin pair processes in organic solar cells — •Alexander J. Kupijai, Florian G. Schaeble, Martin Stutzmann, and Martin S. Brandt — Walter Schottky Institut und Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching

Further improvements of the efficiency of organic solar cells are expected e.g. from advances in chemistry and the optimization of charge carrier transport. We have previously demonstrated that pulsed electrically detected magnetic resonance (pEDMR) and especially electron double resonance (ELDOR) can be used to identify polaron pair recombination as the rate-limiting spin-dependent charge transport mechanism in P3HT/PCBM solar cells at 10 K. We have shown that these multi-frequency measurements can be extended to solar cells containing other polymers such as PCDTBT, where the same polaron pair recombination is observed, suggesting that this recombination is typical for organic solar cells at low temperatures. At room temperature the situation is different, as the negative polaron peak vanishes. Instead, a signal at lower magnetic fields is tentatively attributed to polarons in PEDOT:PSS, which is used as a hole transport layer in the solar cell studied. Again, we use single- and multi-frequency pEDMR techniques to identify the pair processes leading to spin-dependent transport in order to provide information for an optimization of overall solar cell efficiencies.