Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 67: Organic Semiconductors: Solar Cells II (Joint Session with DS/CPP/O)
HL 67.7: Vortrag
Freitag, 26. März 2010, 12:00–12:15, H16
Numerical simulation of s-shaped organic bulk-heterojunction solar cell current--voltage characteristics — •Alexander Wagenpfahl1, Daniel Rauh1, Carsten Deibel1, and Vladimir Dyakonov1, 2 — 1Experimental Physics VI, Julius-Maximilians University of Würzburg, Am Hubland, D-97074 Würzburg — 2Bavarian Center for Applied Energy Research (ZAE Bayern e.V.), Am Hubland, D-97074 Würzburg
Organic solar cell devices based on semiconducting polymer--fullerene blends occasionally possess current--voltage characteristics showing an s-shaped behavior. A strong effect of this kind easily reduces the solar cells working efficiency to a minimum. The detailed origin of the double diode behavior is still unknown. Using a poly(3-hexylthiophene) : phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blend as active layer, we will present how such an s-shape is experimentally achieved using a plasma etch process on the transparent hole conducting anode (indium tin oxide). By considering a finite surface recombination in a device simulation program, we show that this s-shape can be calculated, only by assuming finite charge extraction velocities from the active layer to the metallic electrodes. The resulting charge carrier accumulation at the surfaces thereby changes the current transport from ohmic to space charge limited. By analyzing the found dependencies we will demonstrate under which conditions this effect influences the solar cell performance.