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Improvement of Photovoltaic Response Using Triplet Excitons

Published online by Cambridge University Press:  26 February 2011

Zhihua Xu
Affiliation:
[email protected], University of Tennessee, Knoxville, TN, 37996, United States
Bin Hu
Affiliation:
[email protected], University of Tennessee, knoxville, TN, 37996, United States
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Abstract

We report an enhancement of photovoltaic response by dispersing phosphorescent dye fac tris (2-phenylpyridine) iridium (Ir(ppy)3) in organic solar cells of poly[2-methoxy-5-(2¡¦-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) doped with surface-functionalized fullerene 1-(3-methyloxycarbonyl)propy(1-phenyl [6,6] C61 (PCBM). It is known that photoexcitation generates both singlet and triplet states through intersystem crossing caused by hyperfine or spin-orbital coupling. Due to long diffusion length the triplet excitons can migrate from their generation sites to the interfaces of donor-acceptor interaction and directly dissociate into charge carriers. We found, based on the studies of magnetic field-dependent photocurrent, that the dispersed Ir(ppy)3 molecules increase the spin-orbital coupling strength and triplet density in the MEH-PPV matrix due to the penetration of MEH-PPV π electrons into the large field of orbital dipoles of the Ir(ppy)3. Especially, the triplet excitons facilitate the direct dissociation into charge carriers at the donor-acceptor interacting interfaces in the composite of MEH-PPV and PCBM, and consequently improve the photovoltaic response in organic solar cells.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1 Yu, G., Gao, J., Hummelen, J. C., Wudl, F., and Heeger, A. J., Science 270, 1789 (1995).10.1126/science.270.5243.1789Google Scholar
2 Granström, M., Petritsch, K., Arias, A. C., Lux, A., Anderson, M. R., and Friend, R. H., Nature (London) 395, 257 (1998).10.1038/26183Google Scholar
3 Shaheen, S. E., Brabec, C. J., Sariciftci, N. S., Padinger, F., Fromherz, T., and Hummelen, J. C., Appl. Phys. Lett. 78, 841 (2001).10.1063/1.1345834Google Scholar
4 Xue, J., Uchida, S., Rand, B. P., and Forrest, S. R., Appl. Phys. Lett. 85, 5757 (2004).10.1063/1.1829776Google Scholar
5 Li, G., Shrotriya, V., Huang, J, Yao, Y., Moriarty, T., Emery, K, and Yang, Y., Nature Mater. 4, 864 (2005).10.1038/nmat1500Google Scholar
6 Ma, W. L., Yang, C. Y., Gong, X., Lee, K., and Heeger, A. J., Adv. Funct. Mater. 15,1617 (2005).10.1002/adfm.200500211Google Scholar
7 Köhler, A., Wittmann, H. F., Friend, R. H., Khan, M. S., and Lewis, J., Synth. Met. 77, 147 (1996).Google Scholar
8 Shao, Y. and Yang, Y., Adv. Mater. 17, 2841 (2005).10.1002/adma.200501297Google Scholar
9 Berridge, R., Skabara, P. J., Pozo-Gonzalo, C., Kanibolotsky, A., Lohr, J., McDouall, J. J. W., McInnes, E. J. L., Wolowska, J., Winder, C., Sariciftci, N. S., and Clegg, R. W., J. Phys. Chem. B 110, 3140 (2006).10.1021/jp057256hGoogle Scholar
10 Guo, F. Q., Kim, Y. G., Reynolds, J. R., and Schanze, K. S., Chem. Commun. 17, 1887 (2006).10.1039/B516086CGoogle Scholar
11 Lewis, J., Khan, M. S., Kakkar, A. K., Johnson, B. F. G., Marder, T. B., Fyfe, H.B., Wittmann, F., Friend, R. H., and Dray, A. E., J. Organomet. Chem. 425, 165 (1992).10.1016/0022-328X(92)80033-TGoogle Scholar
12 Kavarnos, G., Cole, T., Scribe, P., Dalton, J. C., and Turro, N. J., J. Am. Chem. Soc. 93, 1032 (1971).Google Scholar
13 Romanova, Z. S., Deshayes, K., and Piotrowiak, P., J. Am. Chem. Soc. 123, 2444 (2001).10.1021/ja002612pGoogle Scholar
14 Frankevich, E. L., Lymarev, A. A., Sokolik, I., Karasz, F. E., Blumstengel, S., Baughman, R. H., and Horhold, H. H., Phys. Rev. B 46, 9320 (1992).10.1103/PhysRevB.46.9320Google Scholar
15 Ito, F., Ikoma, T., Akiyama, K., Watanabe, A., and Kubota, S. T., J. Phys. Chem. B 109, 8707 (2005).10.1021/jp0453212Google Scholar
16 Kalinowski, J., Szmytkowski, J., and Stampor, W., Chem. Phys. Lett. 378, 380 (2003).10.1016/j.cplett.2003.07.010Google Scholar
17 Wohlgenannt, M. and Vardeny, Z. V., J. Phys.: Condens. Mater. 15, R83 (2003).Google Scholar
18 Stubinger, T., and Brutting, W., J. Appl. Phys. 90, 3632 (2001).Google Scholar