Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Focus: Triplet States in Organic Optoelectronics II

CPP 39.3: Vortrag

Mittwoch, 9. März 2016, 15:45–16:00, H37

Quantifying Spin-Dependent Recombination in Organic Bulk Heterojunction Solar Cells — •Stefan Väth¹, Andreas Sperlich¹, Andreas Baumann², and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius Maximilian University of Würzburg, 97074 Würzburg — ²Bavarian Center for Applied Energy Research (ZAE Bayern), 97074 Würzburg

In donor-acceptor (DA) based bulk-heterojunction (BHJ) solar cells, the splitting of singlet excitons at the DA interface is crucially important for charge generation. The reversed process, in which two initially free charge carriers meet at the DA interface and recombine is considered as the main recombination process. The intermediate charge transfer state possesses three triplet and one singlet spin configuration which makes the non-geminate recombination process spin dependent. The role of the spin, however, is under continuous discussion and still not clarified yet.

In our experiments, the influence of spin dependent recombination was investigated for organic BHJ solar cells made of the benchmark material system P3HT:PCBM at real operation conditions. For the first time, we combined electrically detected magnetic resonance (EDMR) with the quantitative technique of open circuit corrected transient charge extraction (OTRACE). Extracting photo generated charges under magnetic resonant conditions compared to non-resonant conditions yields in a spin-dependent contribution to the overall recombination of 0.01 % in this particular solar cell system.