Dephasing Dynamics of the Vibronic States of Epitaxial Polydiacetylene Films

Pham, T. A.; Daunois, A.; Merle, J.‐C.; Moigne, J. Le; Bigot, Jean‐Yves

doi:10.1103/physrevlett.74.904

Cited by 52 publications

(31 citation statements)

References 22 publications

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“…7,62 This suggests that, analogously, some of the fast bath fluctuations that are coupled to the instantaneous eigenstates of the polymer will have a dynamic effect on the electronic energy gaps at the level of the electronic eigenstates. The nuclear motions effecting this should be primarily associated with intramolecular motions, and some evidence that this is the case for epitaxial polydiacetylene films has been reported by Pham et al 63 These workers also reported an excitonic dephasing time of 52 fs.…”

Section: Discussionmentioning

confidence: 92%

Origin of line broadening in the electronic absorption spectra of conjugated polymers: Three-pulse-echo studies of MEH-PPV in toluene

et al. 2000

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Integrated three-pulse stimulated echo peak shift data are compared for N, N-bis-dimethylphenyl-2,4,6,8perylenetetracarbonyl diamide and poly͓2-(2Ј-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene͔ ͑MEH-PPV͒ in toluene solvent. These two molecules represent a model probe of solvation dynamics and a prototypical soluble, electroluminescent conjugated polymer, respectively. The results indicate that it is inappropriate to describe the linear absorption spectrum of MEH-PPV as being primarily inhomogeneously broadened. Conformational disorder along the polymer backbone gives rise to an ensemble of polyene electronic oscillators that are strongly coupled to each other. As a consequence, fluctuations in the electronic energy gap on a time-scale of 50-fs derive primarily from bath-mediated exciton scattering. The data reported here provide an explanation for the broad, structureless electronic absorption of MEH-PPV. This interpretation provides a valuable insight into the nature of the initial photoexcited state, and the efficient population of the emissive state.

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Section: Discussionmentioning

confidence: 92%

Origin of line broadening in the electronic absorption spectra of conjugated polymers: Three-pulse-echo studies of MEH-PPV in toluene

et al. 2000

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“…Among these polymers, the polydiacetylenes ͑PDA's͒ have enjoyed a period of renaissance [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and the synthesis of novel PDA's has enlarged our knowledge on their properties, in particular, on the values of their nonlinear susceptibilities. 15,16 In the last five years we have been interested in the study of a class of attractive PDA's, the polycarbazolyldiacetylenes, 5,[17][18][19][20][21][22] in particular, of poly͓1,6-di ͑ N-carbazolyl͒-2,4-hexadiyne͔͑polyDCHD͒, 5,[19][20][21][22][23][24][25][26] which is, however, insoluble. With the aim of improving its processability we have prepared a modified polyDCHD by inserting long aliphatic chains on the carbazolyl side groups.…”

Section: Introductionmentioning

confidence: 99%

Long-lived photoexcited states in polydiacetylenes with different molecular and supramolecular organization

et al. 1997

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“…For example, this should give rise to an enhancement of the Q 2 /Q CH 2 vibrational modes (C C stretching C Fermi resonance with side-group CH 2 scissors vibration) as discussed in a previous contribution 31 (compare also Ref. 128). The main reason for the change of transition probability for the different vibrational motions is the strong coupling of the considered chain modes to the electron system of the polymer backbone.…”

Section: Spectroscopy In the Time Domainmentioning

confidence: 99%

“…The formation of self-trapped excitons (STE) follows in short time. Pham et al 128 suggested a transition from a butatrienic mesomeric chain structure to an acetylenic one, where the STE is selftrapped in the C C double bonds. The transition to the electronic ground state (with acetylenic backbone structure) therefore should favor the Q 2 mode which is Fermi coupled to the Q CH 2 mode.…”

Section: Spectroscopy In the Time Domainmentioning

confidence: 99%

“…Additionally, owing to the pulse length of approximately 80 fs, the time resolution is at the limit for this experiment as the dynamics of the electronic excited PES are very fast. 31,128,129 In order to separate the chirp effect in this experiment, non-resonant femtosecond time-resolved CARS measurements are in preparation.…”

Section: Spectroscopy In the Time Domainmentioning

confidence: 99%

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A review on linear and non‐linear resonance Raman spectroscopy of the conjugated system polydiacetylene

Materny

Chen

Vierheilig

et al. 2001

J Raman Spectroscopy

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We review resonance Raman investigations of the linear conjugated p-electron system of polydiacetylenes embedded in single-crystalline monomer matrices. Absorption, luminescence, resonance Raman and resonance CARS spectroscopy were used to investigate vibronic properties of the polymers. As an example, we discuss the theoretical model applied for the simulation of the resonance Raman line and excitation profiles obtained from the polymer chains in FBS, TS/FBS and TS6 diacetylene single crystals. The theory is based on a Franck-Condon model, which considers a chain length dependence. The electronic transition energies and matrix elements were calculated by means of an LCAO MO (linear combination of atomic orbitals molecular orbital) calculation in the Hückel approach. An interaction between ensemble and intramolecular properties due to defects can be shown. Besides the well known polymer absorption, the partially polymerized single crystals of the diacetylenes under investigation show blue-shifted absorption bands in sharply separated crystal areas. The spectroscopic investigations of this chromism revealed that most probably growth defects in f111g crystal growth sectors influence the side-group geometry of the polymer chains. Using femtosecond time-resolved CARS spectroscopy, the dynamics of the vibrational excitation in the electronic ground and excited states can be investigated. Here, we report the controlled selective excitation of the polymers. We used a CARS scheme where the difference of pump and Stokes laser wavelengths is chosen to achieve resonance with several chain modes of the polydiacetylenes. By varying the timing and the phases of the femtosecond laser pulses, the timing and the intensity of these modes can be strongly influenced.

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Dephasing Dynamics of the Vibronic States of Epitaxial Polydiacetylene Films

Cited by 52 publications

References 22 publications

Origin of line broadening in the electronic absorption spectra of conjugated polymers: Three-pulse-echo studies of MEH-PPV in toluene

Origin of line broadening in the electronic absorption spectra of conjugated polymers: Three-pulse-echo studies of MEH-PPV in toluene

Long-lived photoexcited states in polydiacetylenes with different molecular and supramolecular organization

A review on linear and non‐linear resonance Raman spectroscopy of the conjugated system polydiacetylene

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