Energy up-conversion in dilute polyfluorene solutions

• Authors: Alexander Kuehne , Allan Mackintosh , David Armstrong , Richard Pethrick
• Languages of publication: EN

Abstracts

EN

Poly(9,9-dioctylfluorene) (PFO) shows highly efficient blue emission with photo excitation occurring between 340–400 nm. Here we show that PFO can in dilute solution emit at a wavelength well below that at which it is being exited. This, we propose is related to an energy transfer from conjugated parts of the polymer chain into more localised states which then emit at a lower wavelength. These localised states can be considered as defects in the conjugation of the polymer or as chain ends. These may produce quasi monomer or quasi dimer species within the chain, which will have a HOMO-LUMO gap of higher energy than the conjugated polymer. These then fluoresce at the lower wavelength; essentially causing, by energy transfer, a process of energy up-conversion. [...]

Keywords

EN

fluorescence; polyfluorene; dilute solution properties; energy up-conversion

• Publisher: De Gruyter Open
• Journal: Open Chemistry
• Year: 2007
• Volume: 5
• Issue: 4
• Pages: 923-930

Dates

published

1 - 12 - 2007

online

1 - 12 - 2007

Contributors

author

Alexander Kuehne

• The Department of Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, G1, 1XL, Glasgow, UK

author

Allan Mackintosh

• The Department of Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, G1, 1XL, Glasgow, UK

author

David Armstrong

• The Department of Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, G1, 1XL, Glasgow, UK

author

Richard Pethrick

• The Department of Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, G1, 1XL, Glasgow, UK

References

• [1] J.H. Burroughes, D.D.C. Bradley, A.R. Brown, R.N. Marks, K. Mackay, R.H. Friend, P.L. Burn and A.B. Holmes: “Light emitting-diodes based on conjugated polymers”, Nature, Vol. 347, (1990), pp. 539–541. http://dx.doi.org/10.1038/347539a0[Crossref]
• [2] M. Gross, D.C. Müller, H.G. Nothofer, U. Scherf, D. Neher, C. Bräuchle and K. Meerholz: “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes”, Nature, Vol. 405, (2000), pp. 661–665. http://dx.doi.org/10.1038/35015037[Crossref]
• [3] Y. Ohmori, M. Uchida, K. Muro and K. Yoshino: “Blue electroluminescent diodes utilizing poly(alkylfluorene)”, Jpn. J. Appl. Phys., Vol. 30, (1991), pp. L1941–L1943. http://dx.doi.org/10.1143/JJAP.30.L1941[Crossref]
• [4] E. Gu, H.X. Zhang, H.D. Sun, M.D. Dawson, A.R. Mackintosh, A.J. C. Kuehne, R.A. Pethrick, C. Belton and D.D.C. Bradley: “Hybrid inorganic/organic microstructured light-emitting diodes produced using photocurable polymer blends”, Appl. Phys. Lett., Vol. 90, (2007), art. 031116. [WoS]
• [5] C. Chi, C. Im and G. Wegner: “Lifetime determination of fluorescence and phosphorescence of a series of oligofluorenes”, J. Chem. Phys., Vol. 124, (2006), art. 024907.
• [6] E. Somma, B. Loppinet, C. Chi, G. Fytas and G. Wegner: “Static and dynamic solution properties of monodisperse oligofluorenes”, Phys. Chem. Chem. Phys., Vol. 8, (2006), pp. 2773–2778. http://dx.doi.org/10.1039/b601531j[Crossref]
• [7] V. Marcon, N. van der Vegt, G. Wegner and G. Raos: “Modeling of molecular packing and conformation in oligofluorenes”, J. Phys. Chem. B, Vol. 110, (2006), pp. 5253–5261. http://dx.doi.org/10.1021/jp056858y[Crossref]
• [8] M.A. Stevens, C. Silva, D.M. Russell and R.H. Friend: “Exciton dissociation mechanisms in the polymeric semiconductors poly.9,9-dioctylfluorene and poly.9,9-dioctylfluorene-co-benzothiadiazole”, Phys. Rev. B, Vol. v, (2001), art. 165213. [Crossref]
• [9] S. Baluschev, T. Mteva, V. Yakutin, G. Nelles, A Yasuda and G. Wegner: “Upconversion fluorescence: Noncoherent excitation by sunlight”, Phys. Rev. Lett., Vol. 97, (2006), art. 143903.
• [10] G. Klaerner and R.D. Miller: “Polyfluorene derivatives: Effective conjugation length from well defined oligomers”, Macromolecules, Vol. 31, (1998), pp. 2007–2009. http://dx.doi.org/10.1021/ma971073e[Crossref]
• [11] L.-O. Pålsson, C.S. Wang, D.L. Russell, A.P. Monkman, M.R. Bryce, G. Rumbles and I.D.W. Samuel: “Photophysics of a fluorene co-polymer in solution and films”, Chem. Phys., Vol. 279, (2002), pp. 229–237. http://dx.doi.org/10.1016/S0301-0104(02)00407-X[Crossref]
• [12] G. Fytas, H.G. Nothofer, U. Scherf, D. Vlassopoulos and G. Meier: “Structure and dynamics of nondilute polyfluorene solutions”, Macromolecules, Vol. 35, (2002), pp. 481–488. http://dx.doi.org/10.1021/ma011416f[Crossref]
• [13] J. Duhamel, A. Yekta, M.A, Winnik, T.C. Jao, M.K. Mishra and I.D. Rubin: “A blob model to study polymer-chain dynamics in solution”, J. Phys. Chem., Vol. 97, (1993), pp. 13708–13712. http://dx.doi.org/10.1021/j100153a046[Crossref]
• [14] W. Chunwaschirasiri, B. Tanto, D.L. Huber and M.J. Winokur: “Chain conformations and photoluminescence of poly(di-n-octylfluorene)”, Phys. Rev. Lett., Vol. 94, (2005), art. 107402.
• [15] M. Annia, M.E. Caruso, S. Lattante and R. Cingolani: “The role of excitons’ quasiequilibrium in the temperature dependence of the poly,9,9-dioctylfluorene tphase photoluminescence”, J. Chem. Phys., Vol. 124, (2006), art. 134707.
• [16] O. Worsfold, J. Hill, S.Y. Heriot, A.M. Fox, D.D.C. Bradley and T.H. Richardson: “Langmuir and Langmui-Blodgett (LB) film properties of poly(9,9-dioctylfluorene)”, Mater. Sci. Eng. C, Vol. 23, (2003), pp. 541–544.
• [17] O. J. Korovyanko and Z.V. Vardeny: “Film morphology and ultrafast photoexcitation dynamics in polyfluorene”, Chem. Phys. Lett., Vol. 356, (2002), pp. 361–367. http://dx.doi.org/10.1016/S0009-2614(02)00349-4[Crossref]
• [18] X. Gong, D. Moses, A.J. Heeger and S. Xiao: “Excitation energy transfer from polyfluorene to fluorene defects”, Synth. Met., Vol. 141, (2004), pp. 17–20. http://dx.doi.org/10.1016/j.synthmet.2003.06.003[Crossref]
• [19] J. Frahn, B. Karakaya, A. Schäfer and A.D. Schlüter: “Suzuki polycondensation: “On catalyst derived phosphorus incorporation and reproducibility of molecular weights”, Tetrahedron, Vol. 53 (1997), pp. 15459–15467. http://dx.doi.org/10.1016/S0040-4020(97)00973-3[Crossref]
• [20] T.P. Nguyen: “Defect analysis in organic semiconductors”, Mater. Sci. Semicond. Process, Vol. 9, (2006), pp. 198–203. http://dx.doi.org/10.1016/j.mssp.2006.01.060[Crossref]

Identifiers

DOI

10.2478/s11532-007-0051-7