Time-resolved photoluminescence from poly[2-methoxy, 5-(2′-ethyl-hexyloxy)-<i>p</i>-phenylene-vinylene]: Solutions, gels, films, and blends

Smilowitz, Laura; Hays, A. K.; Heeger, Alan J.; Wang, G.; Bowers, John E.

doi:10.1063/1.464790

Cited by 127 publications

(84 citation statements)

References 16 publications

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“…19,20 For the bilayer (see Table I) the lifetime term τ r 1 is assigned as the recombination lifetime of the MEH PPV acceptor. The value of 277 ps for the MEH PPV at room temperature is in agreement with other results in the literature 11,21 although this lifetime can depend on the average conjugation length of the polymer. The term τ r 2 = 683 ps is interpreted as a recombination of more complex MEH PPV mixing states at the interface of the bilayer.…”

supporting

confidence: 80%

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Long range energy transfer in conjugated polymer sequential bilayers

Cury

Bourdakos

Dai

et al. 2011

The Journal of Chemical Physics

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Steady-state and time-resolved photoluminescence have been used to investigate the optical properties of bilayer and blend films made from poly(9,9-dioctyl-fluorene-2,7-diyl) (PFO) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH PPV). Energy transfer has been observed in both systems. From steady-state photoluminescence measurements, the energy transfer was characterized by the effective enhancement of the MEH PPV emission intensity after exciting the donor states. Relatively faster decays for the PFO donor emission have been observed in the blends as well as in the bilayer structures, confirming effective energy transfer in both structures. In contrast to the bilayers, the time decay of the acceptor emission in the blends presents a long decay component, which was assigned to the exciplex formation in these samples. For the blends the acceptor emission is in fact a composition of exciplex and MEH PPV emissions, the later being due to Förster energy transfer from PFO. In the bilayers, the exciplex is not observed and temperature dependence photoluminescence measurements show that exciton migration has no significant contribution to the energy transfer. The efficiency and very long range of the energy transfer in the bilayers is explained assuming a surface-surface interaction geometry where the donor/acceptor distances involved are much longer than the common Förster radius.

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confidence: 80%

“…Shorter PL lifetime of 200 ps has been measured for the MEH PPV in a blend with polyethylene (PE). 11 This lifetime is inside the range of 200-500 ps reported for the MEH PPV in solution, [11][12][13] in solid state film and in a MEH PPV/PE gel.…”

Section: Resultsmentioning

confidence: 80%

Long range energy transfer in conjugated polymer sequential bilayers

Cury

Bourdakos

Dai

et al. 2011

The Journal of Chemical Physics

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“…Therefore the k 0 isc values determined using this model are molecule-specific and independent of other parameters taken from ensemble measurements, that is, fluorescence lifetime, singlet-to-triplet quantum yield, or molecule volume. For the MEH-PPV molecules investigated, the values for k 0 isc of (6.5 AE 3.0) 10 3 s À1 (300 K) and (2.7 AE 0.8) reported values, [30][31][32][33][34][35][36][37] [a] The molecular volume of 10 3 nm 3 and the t fl of 300 ps [44] are used.…”

Section: Excitation Intensity Modulation Smsmentioning

confidence: 99%

Variable Temperature Single‐Molecule Dynamics of MEH‐PPV

et al. 2005

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Herein, we continue our investigation of the single-molecule spectroscopy of the conjugated polymer poly[2-methoxy,5-(2'-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) at cryogenic temperatures. First, the low temperature microsecond dynamics of single MEH-PPV conjugated polymer molecules are compared to the dynamics at room temperature revealing no detectible temperature dependence. The lack of temperature dependence is consistent with the previous assignment of the dynamics to a mechanism that involves intersystem crossing and triplet-triplet annihilation. Second, the fluorescence spectra of single MEH-PPV molecules at low temperature are studied as a function of excitation wavelength (i.e. 488, 543, and 568 nm). These results exhibit nearly identical fluorescence spectra for different excitation wavelengths. This strongly suggests that electronic energy transfer occurs efficiently to a small number of low-energy sites in the multichromophoric MEH-PPV chains.

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“…[20][21][22] We argue that diffusion to impurity-related recombination centers is an important quenching mechanism in PPV-related materials.…”

Section: B Efficiency and Quenching Mechanismsmentioning

confidence: 99%

Solid-state-concentration effects on the optical absorption and emission of poly(p-phenylene vinylene)-related materials

et al. 1996

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We present measurements of the optical absorption and emission properties of poly(p-phenylene vinylene͒ ͑PPV͒ -related materials focusing on the differences between molecules isolated by dispersion in an inert host and concentrated molecular films. Optical absorption spectra, photoluminescence ͑PL͒ spectra, PL efficiency, and time-resolved PL spectra of dilute blends of PPV oligomers with 2-5 phenylene-phenyl rings are compared with those of dense oligomer and polymer films. In dilute oligomer-poly͑methyl methacrylate͒ ͑PMMA͒ blends with high PL efficiency, the PL decay is exponential, independent of both temperature and oligomer length. This implies that the fundamental radiative lifetime of PPV oligomers is essentially independent of oligomer length. Concentrated spin-cast oligomer films and polymers have a faster and strongly temperaturedependent PL decay that approaches that of the dilute oligomer results at low temperature. The differences in PL decay correspond to changes in PL efficiency. The efficiency of the oligomer-PMMA blend is high and only weakly temperature dependent, whereas that of concentrated films is lower and strongly temperature dependent, decreasing by more than a factor of 3 from 10 to 350 K. The quenching of the PL efficiency in concentrated films is due to migration to extrinsic, impurity related centers as opposed to an intrinsic intermolecular recombination process. The PL spectrum of a dilute oligomer blend redshifts substantially, both as the excitation energy is decreased and as the emission time increases. This spectral redshift is due to disorderinduced site-to-site variation and not to diffusion to lower-energy sites. In contrast, no spectral shift with excitation energy or emission time was observed for dense oligomer films. ͓S0163-1829͑96͒03132-3͔

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Time-resolved photoluminescence from poly[2-methoxy, 5-(2′-ethyl-hexyloxy)-p-phenylene-vinylene]: Solutions, gels, films, and blends

Cited by 127 publications

References 16 publications

Long range energy transfer in conjugated polymer sequential bilayers

Long range energy transfer in conjugated polymer sequential bilayers

Variable Temperature Single‐Molecule Dynamics of MEH‐PPV

Solid-state-concentration effects on the optical absorption and emission of poly(p-phenylene vinylene)-related materials

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