Financial support by the Thuringian Ministry of Culture (“NANORG1” 20101276) is gratefully acknowledged by HH, TE, and GG.
Effects of Annealing on the Nanomorphology and Performance of Poly(alkylthiophene):Fullerene Bulk-Heterojunction Solar Cells†
Article first published online: 12 MAR 2007
Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 17, Issue 7, pages 1071–1078, May, 2007
How to Cite
Nguyen, L. H., Hoppe, H., Erb, T., Günes, S., Gobsch, G. and Sariciftci, N. S. (2007), Effects of Annealing on the Nanomorphology and Performance of Poly(alkylthiophene):Fullerene Bulk-Heterojunction Solar Cells. Adv. Funct. Mater., 17: 1071–1078. doi: 10.1002/adfm.200601038
- Issue published online: 25 APR 2007
- Article first published online: 12 MAR 2007
- Manuscript Revised: 29 DEC 2006
- Manuscript Received: 1 NOV 2006
- Thuringian Ministry of Culture. Grant Number: “NANORG1” 20101276
- Solar cells;
- Structure–property relationships
The evolution of nanomorphology within thin solid-state films of poly(3-alkylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester (P3AT:PCBM) blends during the film formation and subsequent thermal annealing is reported. In detail, the influence of the P3AT's alkyl side chain length on the polymer/fullerene phase separation is discussed. Butyl, hexyl, octyl, decyl, and dodecyl side groups are investigated. All of the P3ATs used were regioregular. To elucidate the nanomorphology, atomic force microscopy (AFM), X-ray diffraction, and optical spectroscopy are applied. Furthermore, photovoltaic devices of each of the different P3ATs have been constructed, characterized, and correlated with the nanostructure of the blends. It is proposed that the thermal-annealing step, commonly applied to these P3AT:PCBM blend films, controls two main issues at the same time: a) the crystallization of P3AT and b) the phase separation and diffusion of PCBM. The results show that PCBM diffusion is the main limiting process for reaching high device performances.