Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Halbleiterphysik

HL 50: Poster II

HL 50.40: Poster

Donnerstag, 30. März 2006, 16:30–19:00, P3

Investigation of electric field- and illumination intensity dependent recombination losses in polymer-fullerene bulk heterojunction solar cells — •Jörg Bösner¹, Vladimir Dyakonov^1,2, and Ingo Riedel¹ — ¹Bavarian Centre for Applied Energy Research (ZAE-Bayern e.V.), Div. Functional Materials for Energy Technology, Am Hubland, D-97074 Würzburg, Germany — ²Experimental Physics VI, Institute of Physics, University of Würzburg, Am Hubland, 97074 Würzburg, Germany

Organic bulk heterojunction solar cells based on P3HT:PCBM composites were studied by measurements of the current-voltage characteristics (IV) and the external quantum efficiency (EQE) under variable electrical and optical bias. In EQE measurements, the simultaneous application of a white bias light results in the partial filling of traps and accounts for the presence of bimolecular recombination losses observed at higher light intensities. Spectral changes of the EQE under variable optical bias are correlated with the scaling exponents of the integral short circuit current (J_SC) with light intensity. At zero bias the J_SC in polymer-fullerene devices is primarily driven by the internal field. Hence, the mobility-lifetime product (µτ) of majority charge carriers determines dependence of the photocurrent J_ph on the applied voltage. At high reverse bias, the field-dependent J_ph saturates and reflects the maximum J_SC which can be used to estimate the µτ-product of photogenerated charge carriers. The electrical bias dependence of the EQE used to analyze the field-dependent recombination losses observed in the current-voltage characteristics under illumination.