Regensburg 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 61: Organic Electronics and Photovoltaics I (jointly with CPP, DS, and HL)
O 61.7: Vortrag
Donnerstag, 14. März 2013, 11:30–11:45, H34
Charge Generation in PBDTTPD:PCBM and Si-PCPDTBT:PCBM Solar Cells: The Influence of Excess Photon Energy and Electronic Energy Level Offsets — •Steve Albrecht1, Koen Vandewal2, Alberto Salleo2, and Dieter Neher1 — 1University of Potsdam, Soft Matter Physics, Potsdam, Germany — 2Stanford University, Department of Materials Science and Engineering, Stanford, USA
In the last years a dramatic increase in organic solar cell efficiency has been reported with polymers and fullerene derivatives processed from solution. However, the fundamental process involved in the conversion of absorbed photons to free charges is still not fully understood. In this work, we use time delayed collection field (TDCF) [1] with variable excitation wavelength to gain inside into the effect of the excess photon energy on the quantum efficiency and field-dependence of free charge carrier generation. With two high efficiency model systems showing either field independent CT-state splitting (PBDTTPD:PCBM) or a weak field-dependence of free charge formation (Si-PCPDTBT:PCBM), we show how the field-dependence changes with direct CT state excitation in the absorption region below the band-gap. Additionally, we show how generation and bimolecular recombination is affected when the fullerene derivative PCBM is exchanged by higher LUMO adducts ICMA, ICBA or ICTA with reduced driving force for CT-state splitting.
[1] Albrecht, S.; Janietz, S.; Schindler, W.; Frisch J.; Neher D., Journal of the American Chemical Society 134 (36), 14932 (2012).