Synthesis and luminescence properties of three novel polyfluorene copolymers

Charas, Ana; Morgado, Jorge; Martinho, J. M. G.; Alcácer, Luís; Lim, Shuang-Fang; Friend, Richard H.; Cacialli, Franco

doi:10.1016/s0032-3861(03)00028-4

Cited by 78 publications

(56 citation statements)

References 42 publications

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“…Similarly, a linear increase in fluorescence with concentration was observed. The precipitation probably results from association of PBS-PFP aggregates in solution, which have previously been reported for p-phenylene and fluorene based polymers [4,20,27,28], and other conjugated polyelectrolytes [29]. The absorbance behaviour will be further discussed with electrical conductivity results in Section 3.3.…”

Section: Behaviour Of Pbs-pfp In Aqueous Solutionmentioning

confidence: 63%

“…4). We have suggested [20] that the spectral changes, which are very similar to those observed with a phenyl-fluorene copolymer on going from thin films to isolated polymer molecules in solvents such as cyclohexane [28], are due to break up of PBS-PFP aggregates by the solvent. It is noteworthy that these properties change in the vicinity of the cmc of C 12 E 5 (5 ± 2 × 10 −5 mol dm −3 [31]).…”

Section: Fluorescence Spectral and Lifetime Measurementsmentioning

confidence: 67%

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Interactions between surfactants and {1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}

Burrows

Lobo

Pina

et al. 2005

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The interaction between the water-soluble anionic conjugated copolymer poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} (PBS-PFP) and various surfactants has been studied in aqueous solution by UV-vis absorption spectra, fluorescence and electrical conductivity. It is suggested from the linear dependence of absorbance, fluorescence and electrical conductivity on concentration that in the absence of surfactant, moderately stable dispersions are formed. These are affected in different ways on adding cationic, anionic or neutral surfactants. With the cationic cetyltrimethylammonium bromide, quenching of fluorescence intensity and lifetime, and formation of a new emission occurs at concentrations well below the critical micelle concentration (cmc). Electrical conductivity measurements indicate a discontinuity at surfactant/polymer ratio corresponding to electroneutrality, due to complexation. With the anionic sodium dodecyl sulfate, fluorescence quenching is also observed, but is attributed to formation of some mixed polymer/surfactant aggregate. The most striking changes are observed with the non-ionic pentaethyleneglycol monododecyl ether (C 12 E 5 ), where a blue shift in fluorescence emission, dramatic increases in lifetime and quantum yield, and changes in electrical around the cmc are interpreted in terms of incorporation of single polymer chains in elongated cylindrical micelles. This is supported by 1 H NMR spectroscopic measurements.

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Section: Behaviour Of Pbs-pfp In Aqueous Solutionmentioning

confidence: 63%

Section: Fluorescence Spectral and Lifetime Measurementsmentioning

confidence: 67%

Interactions between surfactants and {1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}

Burrows

Lobo

Pina

et al. 2005

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…The EL emission spectrum was entirely the same as PL emission, and U These pioneering works stimulated recent research activities towards incorporation of the thiophene-S,S-dioxide unit into various copolymers, and PLEDs built with such copolymers were reported by several groups. Charas et al studied PLEDs based on copolymer 44 (obtained by Suzuki coupling of 2,5-dibromothiophene-S,S-dioxide with the diboronic ester of 9,9-bis(2-ethylhexyl)fluorene [87] ) and its blends with poly(9,9-dioctylfluorene) homopolymer (PFO). [88] Copoly- .…”

Section: Oligomers and Polymers With The Thiophene-ss-dioxide Moietymentioning

confidence: 99%

Light‐Emitting Polythiophenes

et al. 2005

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Polythiophenes are one of the most important classes of conjugated polymers, with a wide range of applications, such as conducting films, electrochromics, and field‐effect transistors, which have been the subject of a number of older and more recent reviews. Much less attention has been paid to the light‐emitting properties of this class of materials, although their unique properties present a number of opportunities unavailable from more popular polymeric light emitters such as polyfluorene or poly(p‐phenylene vinylene). This article reviews achievements to date in applications of thiophene‐based polymers and oligomers as electroluminescent materials. We demonstrate the basic principles of controlling the optical properties of polythiophenes through structural modifications and review the most important light‐emitting materials created from thiophene derivatives. Special attention is paid to consequences of structural variations on the performance of light‐emitting diodes fabricated with these materials.

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“…It was found that the full width at half-maximum (fwhm A ) of the theoretical absorption band with Boltzmann weight considered is 4839 cm 21 (0.60 eV) indicated in Figure 6, which in good agreement with the experimental band (4900 cm 21 or 0.61 eV). 11 Our work also presented the absorption band of the FEDOT dimer, as shown in Figure 7. It was found that the redshift occurred in the dimer because of the increase of the conjugation length.…”

Section: Absorption Spectra Of Fedot and Ftso2 Monomers And Dimersmentioning

confidence: 70%

“…The advantage of such a copolymer is that the thiophene unit is easy to modify in order to enhance the optical and electronic properties. It was found that ethylenedioxythiophene [6][7][8] and S,S-dioxide-thiophene [9][10][11] can be introduced in copolymerization in order to obtain easier charge transfer at the interfaces, as well as radiative recombination into the polymer. However, modification of the structure in order to improve the drawbacks involves not only the actual synthesis, but also theoretical calculations.…”

Section: Introductionmentioning

confidence: 99%

Investigation of excited‐state properties of fluorene–thiophene oligomers by the SAC‐CI theoretical approach

Poolmee

Hannongbua

2010

J Comput Chem

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Excited states of fluorene-ethylenedioxythiophene (FEDOT) and fluorene-S,S-dioxide-thiophene (FTSO2) monomers and dimers were studied by the symmetry-adapted cluster (SAC)-configuration interaction (CI) method. The absorption and emission peaks observed in the experimental spectra were theoretically assigned. The first three excited states of the optimized conformers, and the conformers of several torsional angles, were computed by SAC-CI/D95(d). Accurate absorption spectra were simulated by taking the thermal average for the conformers of torsional angles from 0 degrees to 90 degrees. The conformers of torsional angles 0 degrees, 15 degrees, and 30 degrees mainly contributed to the absorption spectra. The full width at half-maximum of the FEDOT absorption band is 0.60 eV (4839 cm(-1)), which agrees very well with the experimental value of 0.61 eV (4900 cm(-1)). The maximum absorption wavelength is located at 303 nm, which is close to those of the experimental band (327 nm). The calculated absorption spectrum of FTSO2 showed two bands in the range of 225-450 nm. This agrees very well with the available experimental spectrum of a polymer of FTSO2, where two bands are detected. The excited-state geometries were investigated by CIS/6-31G(d). These showed a quinoid-type structure which exhibited a shortening of the inter-ring distance (0.06 A for FEDOT and 0.04 A for FTSO2). The calculated emission energy of FEDOT is 3.43 eV, which agrees very well with the available experimental data (3.46 eV). The fwhm(E) is about 0.49 eV (3952 cm(-1)), while the experimental fwhm is 0.43 eV (3500 cm(-1)). For FTSO2, two bands were also found in the emission spectrum.

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Synthesis and luminescence properties of three novel polyfluorene copolymers

Cited by 78 publications

References 42 publications

Interactions between surfactants and {1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}

Interactions between surfactants and {1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}

Light‐Emitting Polythiophenes

Investigation of excited‐state properties of fluorene–thiophene oligomers by the SAC‐CI theoretical approach

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