Hedley, G. J. , Ward, A. J., Alekseev, A. , Howells, C. T., Martins, E. R., Serrano, L. A., Cooke, G. , Ruseckas, A. and Samuel, I. D.W. (2013) Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells. Nature Communications, 4, 2867. (doi: 10.1038/ncomms3867) (PMID:24343223) (PMCID:PMC3905772)
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Abstract
The morphology of bulk heterojunction organic photovoltaic cells controls many of the performance characteristics of devices. However, measuring this morphology is challenging because of the small length-scales and low contrast between organic materials. Here we use nanoscale photocurrent mapping, ultrafast fluorescence and exciton diffusion to observe the detailed morphology of a high-performance blend of PTB7:PC71BM. We show that optimized blends consist of elongated fullerene-rich and polymer-rich fibre-like domains, which are 10–50 nm wide and 200–400 nm long. These elongated domains provide a concentration gradient for directional charge diffusion that helps in the extraction of charge pairs with 80% efficiency. In contrast, blends with agglomerated fullerene domains show a much lower efficiency of charge extraction of ~45%, which is attributed to poor electron and hole transport. Our results show that the formation of narrow and elongated domains is desirable for efficient bulk heterojunction solar cells.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Serrano Gonzalez, Mr Luis and Alekseev, Dr Alexander and Hedley, Dr Gordon and Cooke, Professor Graeme |
| Authors: | Hedley, G. J., Ward, A. J., Alekseev, A., Howells, C. T., Martins, E. R., Serrano, L. A., Cooke, G., Ruseckas, A., and Samuel, I. D.W. |
| College/School: | College of Science and Engineering > School of Chemistry College of Science and Engineering > School of Physics and Astronomy |
| Journal Name: | Nature Communications |
| Publisher: | Nature Publishing Group |
| ISSN: | 2041-1723 |
| ISSN (Online): | 2041-1723 |
| Copyright Holders: | Copyright © 2013 Hedley, G.J. et al. |
| First Published: | First published in Nature Communications 4:2867 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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