Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DS: Fachverband Dünne Schichten

DS 6: [HL] Organic Semiconductors: Solar Cells (Joint Session DS/CPP/HL/O)

DS 6.5: Vortrag

Montag, 22. März 2010, 17:00–17:15, H15

Relation of open circuit voltage to charge carrier concentration in organic bulk heterojunction solar cells — •Daniel Rauh¹, Alexander Wagenpfahl², Carsten Deibel², and Vladimir Dyakonov^1,2 — ¹Bavarian Centre for Applied Energy Research e.V. (ZAE Bayern), D-97074 Würzburg — ²Julius-Maximilians-University of Würzburg, Institute of Physics, Experimental Physics VI, D-97074 Würzburg

A deeper understanding of the open circuit voltage V_oc in bulk heterojunction solar cells is crucial for further performance enhancements. In order to investigate V_oc, we measured temperature dependent current–voltage characteristics of poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) solar cells (pristine and annealed) at various light intensities. With charge extraction measurements under the same conditions we could determine the corresponding charge carrier densities n in the operating device. Extrapolating V_oc to T=0K gives a constant value for all intensities indicating the effective bandgap of the donor–acceptor system. Fitting the data with V_oc models [1,2] showed excellent agreement with only one free parameter, the effective density of states. From our analysis, we gain insights into the recombination meachanisms limiting V_oc.

[1] Koster et al., Appl. Phys. Lett. 86, 123509 (2005)

[2] Cheyns et al., Phys. Rev. B 77, 165332 (2008)