Triplet excimer emmission from carbazoyl chromophores in polystyrene matrices

Abia, A. A.; Burkhart, Richard D.

doi:10.1021/ma00142a052

Cited by 9 publications

(13 citation statements)

References 6 publications

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“…In addition, there is kinetic evidence for the presence of intermolecular triplet excimers in fluid solutions of aromatic thione and C 70 . For solid films of polyvinylnaphthalenes, , poly(vinylcarbazole), and related polymers, , as well as molecularly doped polymers, − there have been a number of rather convincing reports of triplet excimer formation. A comprehensive listing of the polymeric systems is given in ref .…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Emission Studies of Intermolecular Triplet Excimers in Fluid Solutions: Dibenzofuran and Dibenzothiophene Revisited

et al. 1999

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In fluid solutions at room temperature, the high-purity dibenzofuran (DBF) and dibenzothiophene (DBT) exhibit phosphorescence and delayed fluorescence from monomers as well as intermolecular triplet excimers. The delayed emissions assigned to the excimer are red shifted with respect to the corresponding emissions from the monomers. All four delayed emissions exhibit excitation spectra that are identical with the excitation spectrum of the prompt fluorescence of the corresponding monomer. Consistent with an emission originating from the bimolecular annihilation of the triplet excimers, the delayed excimer fluorescence is spectrally very similar to the normal excimer fluorescence of the compounds, and it decays with a lifetime which is one-half the decay time of the excimer phosphorescence. At longer delay times, where the triplet excimer−monomer equilibration is expected to occur, the ratio of the intensity of the excimer phosphorescence to that of the monomer phosphorescence becomes independent of time. Concomitantly, the lifetimes of the two emissions become identical to each other, as indicated by the very similar lifetimes of the delayed excimer fluorescence and the delayed monomer fluorescence. These results confirm the formation of intermolecular triplet excimers in fluid solutions of these compounds.

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Section: Introductionmentioning

confidence: 99%

Time-Resolved Emission Studies of Intermolecular Triplet Excimers in Fluid Solutions: Dibenzofuran and Dibenzothiophene Revisited

et al. 1999

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“…A graph of In (lOOA-) vs. time is presented in Figure 4. A slight nonlinearity is observed for 200-300 ms following excitation, but the remainder of the decay shows good linearity with a lifetime of 6.9 ± 0.3 s. The phosphorescence decay of NEC in a polystyrene matrix at 77 K has also been measured, yielding a value of 6.5 ± 0.3 s. 10 The source of the persistent nonlinearity in the data of Figure 3 is thought to be due primarily to interference from second-order T-T annihilation reactions leading to delayed fluorescence. Delayed fluorescence is, of course, a prominent emission feature of PVK both in frozen solutions and in neat films.…”

Section: Resultsmentioning

confidence: 91%

“…The question has some importance, however, because it bears on the dimensionality of the process. If the exciton has three translational degrees of freedom, then a diffusion-con-trolled annihilative process would be calculated by kA = AicrDN/im (10) in units of M'1 s'1. Here N is Avogradro's number, r is the encounter distance, and D is the diffusion coefficient.…”

Section: Discussionmentioning

confidence: 99%

Triplet-state absorption and decay kinetics of poly(N-vinylcarbazole) and N-ethylcarbazole by a laser excitation-optical probe method

Caldwell¹,

Burkhart²

1986

Macromolecules

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“…(3) No emission at 510 nm is observed from polymers that do not contain a naphthalene cap. (4) The lifetimes of the AC emission and of the naphthalenic one are very similar both at 77 K and at ambient temperature when 337-nm excitation is used.…”

Section: Discussionmentioning

confidence: 89%

End injection of triplet electronic excitation energy into a polymer molecule using chromophores bound at chain ends

Burrows¹,

Haggquist²,

Burkhart³

1990

Macromolecules

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Polystyrene molecules labeled at opposite ends with naphthalene and aromatic carbonyl (AC) groups were prepared and their triplet photophysical properties investigated. By use of excitation at 337 nm the aromatic carbonyl was photoexcited selectively and time-resolved phosphorescence spectra were recorded at delay times from 100 ps to 100 ms. The AC phosphorescence was inhomogeneously broadened at the shortest delay times but becomes narrow and more structured with increasing delay time at 77 K. At ambient temperature the spectrum remains broad and structureless even at long delay times. Using dye laser excitation at 360 nm a narrow structured band is observed even at 150 ps after the excitation pulse. Energy transfer to the naphthalene group occurs efficiently and may take place either by direct transfer from excited AC groups or by an indirect process involving backbone phenyl groups. Electronically excited phenyl groups are thought to be produced by energy transfer from that set of triplet AC chromophores lying at the high-energy edge of the inhomogeneously broadened manifold. The resulting emission spectrum suggests the possibility of exciplex formation.

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Triplet excimer emmission from carbazoyl chromophores in polystyrene matrices

Abstract: Note that eq 24 and 31 are identical. We simply use eq 32 in place of eq 27 when the single-liquid approximation is assumed for Y.

Cited by 9 publications

References 6 publications

Time-Resolved Emission Studies of Intermolecular Triplet Excimers in Fluid Solutions: Dibenzofuran and Dibenzothiophene Revisited

Time-Resolved Emission Studies of Intermolecular Triplet Excimers in Fluid Solutions: Dibenzofuran and Dibenzothiophene Revisited

Triplet-state absorption and decay kinetics of poly(N-vinylcarbazole) and N-ethylcarbazole by a laser excitation-optical probe method

End injection of triplet electronic excitation energy into a polymer molecule using chromophores bound at chain ends

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