Comparison of Bimolecular Charge Carrier Recombination in p-conjugated Polymers and Bulk-Heterojunction Solar Cells
A. Pivrikas, R. Ostenbacka, G. Juska, K. Arlauskas, M. Scharber, A.J. Mozer and N.S. Sariciftci
By using Time-of-Flight technique we have measured charge carrier transport and recombination in the p-conjugated polymer regio-random poly(3-hexylthiophene (RRaPHT) and in two types of bulk-heterojunction solar-cells, namely in a blend of regioregular poly(3-hexylthiophene) mixed with 1-(3-methoxycarbonyl)propyl-1- phenyl-[6, 6]-methanofullerene (RRPHT/PCBM) and in the blend of poly[2-methoxy-5-(3, 7-dimethyloctyloxy)-phenylene vinylene] mixed with PCBM (MDMO:PPV/PCBM). We found Langevin-type charge carrier recombination in pure RRaPHT and in the MDMO:PPV/PCBM blend, while greatly reduced bimolecular recombination (compared to Langevin-type) was observed in the RRPHT/PCBM solar cell.