A comparative site-selective fluorescence study of ladder-type para-phenylene oligomers and oligo-phenylenevinylenes

Pauck, T.; Bäßler, H.; Grimme, Julian; Scherf, Ullrich; Müllen, Kläus

doi:10.1016/0301-0104(96)00062-6

Cited by 45 publications

(53 citation statements)

References 16 publications

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“…A comparison with measured fluorescence spectra of different oligomers [5] shows qualitative agreement, i.e., they show a broad S 1 ← S 0 transition which is shifting to lower energies with increasing system size. As one would expect for the S 1 state, the HOMO-LUMO excitation is the dominant one.…”

Section: B Optical Spectramentioning

confidence: 66%

“…Therefore, no explanation of the abatic onset of the photocurrent in LPPP films can be given at this level of a microscopic theory. [2], [6] [4], [5] |∆r C−C | = Sum of the differences of the C-C bond lengths with respect to the optimized structure at MP2 level …”

Section: Discussionmentioning

confidence: 99%

“…As a consequence, the π-system might spread out over an entire polymer and a vibronic resolution of the S 1 ← S 0 transition is discernible [2]. In order to deduce some characteristics of the polymeric films [3], like the effective conjugation length, several oligomers have been synthesized in the past to study the low-lying electronic excited states of the polymer [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Excited states of ladder-type poly-p-phenylene oligomers

et al. 2001

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Ground state properties and excited states of ladder-type paraphenylene oligomers are calculated applying semiempirical methods for up to eleven phenylene rings. The results are in qualitative agreement with experimental data. A new scheme to interpret the excited states is developed which reveals the excitonic nature of the excited states. The electron-hole pair of the S 1 -state has a mean distance of approximately 4Å.

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Section: B Optical Spectramentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Excited states of ladder-type poly-p-phenylene oligomers

et al. 2001

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“…[73,76,77] These limitations can be overcome in part by ensemble linenarrowing techniques, such as hole-burning and site-selective spectroscopy. Narrow ZPLs with associated PSBs have indeed been resolved by low-temperature site-selective fluorescence spectroscopy on very short oligo(p-phenylene-vinylenes) as well as ladder-type oligo(p-phenylenes) with up to four repeat units, [10,78,79] which indicate weak electron-phonon coupling to low-energy vibrations in these oligomers. However, for longer oligomers and the corresponding polymers [(Me)LPPP, PPV] both site-selective and hole-burning spectroscopy yielded broad and structureless bands with linewidths of the order of 100 cm À1 .…”

Section: Discussionmentioning

confidence: 98%

Single‐Molecule Spectroscopy on a Ladder‐Type Conjugated Polymer: Electron–Phonon Coupling and Spectral Diffusion

Hildner¹,

Winterling²,

Lemmer³

et al. 2009

ChemPhysChem

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We employ low-temperature single-molecule spectroscopy combined with pattern recognition techniques for data analysis on a methyl-substituted ladder-type poly(para-phenylene) (MeLPPP) to investigate the electron-phonon coupling to low-energy vibrational modes as well as the origin of the strong spectral diffusion processes observed for this conjugated polymer. The results indicate weak electron-phonon coupling to low-frequency vibrations of the surrounding matrix of the chromophores, and that low-energy intrachain vibrations of the conjugated backbone do not couple to the electronic transitions of MeLPPP at low temperatures. Furthermore, these findings suggest that the main line-broadening mechanism of the zero-phonon lines of MeLPPP is fast, unresolved spectral diffusion, which arises from conformational fluctuations of the side groups attached to the MeLPPP backbone as well as of the surrounding host material.

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“…1(b)] suggests that type I spectra represent emission from the delocalized lower exciton state while type II spectra are attributed to monomer-type emission from a localized state. The loss of vibronic structure in type I spectra is attributed to a collective mode operative in the exciton state [17]. In particular, we assume that a low frequency torsional motion in the soft interchromophore potential couples strongly to the delocalized electronic excitation smearing out the vibronic structure.…”

mentioning

confidence: 99%