Effect of Cis-Backbone on Optical Properties of Polyphenylacetylene

Abstract:

By controlling the temperature of chemical reaction, we synthesized four polyphenylacetylene samples, in which the percentages of cis configurations were determined to be 65, 75, 85 and 100%, respectively. Ultraviolet-visible and fluorescence studies show that the cis-configured backbones have posed significant effects on the optical absorption and fluorescence of the polyphenylacetylenes. Upon the 325-nm excitation, the dilute solutions of these cis-polyphenylacetylenes give off weak fluorescence with their peak located at about 390 nm, but the concentrated solutions of the polymer can give off strong orange-red fluorescence with their peak located at about 600 nm. With Hückel tight binding theory, both the E-k dispersion relations and the density of states were calculated for cis-polyphenylacetylene. Our results suggest that the blue photoluminescence of polyacetylenes origins from the backbone enhanced -conjugation of the phenyl chromophors in the polymer, and that intermolecular interactions can occur in the excited complex of the polymer.

• Periodical: Key Engineering Materials (Volumes 428-429)
• Pages: 483-486
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.428-429.483
• Online since: January 2010
• Authors: Bao Gai Zhai, Yuan Ming Huang
• Keywords: Absorption, Electronic Structure, Photoluminescence (PL), Polyphenylacetylene

References

[1] Y. M. Huang, J. W. Y. Lam, K. K. L. Cheuk, W. Ge, and B. Z. Tang: Macromolecules, Vol 32 (1999), p.5979.

[2] Y. M. Huang, W. Ge, J. W. Y. Lam, and B. Z. Tang: Appl. Phys. Lett., Vol 75 (1999), p.4094.

[3] Y.M. Huang, F. -F. Zhou, Y. Deng and B. -G. Zhai: Solid State Ionics, Vol 179 (2008), p.1305.

[4] Y.M. Huang, W.K. Ge, J.W.Y. Lam and B.Z. Tang: Appl. Phys. Lett., Vol 78 (2001), p.1652.

[5] Y.M. Huang, F. Zhou and K. Xu: Appl. Phys. Lett., Vol 88 (2006), p.131112.