Photoluminescence and excimer emission of functional groups in light‐emitting polymers

Fehervari, Agota F.; Kagumba, Lawino; Hadjikyriacou, Savvas; Chen, Freeman; Gaudiana, Russell

doi:10.1002/app.11606

Cited by 16 publications

(17 citation statements)

References 15 publications

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“…This band might correspond to the excimer transitions of phenyl groups closely located on the silica surface. [32][33][34] A similar PL band was also observed in poly(diphenylsilylcarbodiimide) 12 and attributed to phenyl excimers.…”

Section: Pl Emissionsupporting

confidence: 62%

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Vasin

Kysil

Lajaunie

et al. 2018

Journal of Applied Physics

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Fumed silica with a specific area of 295 m 2 /g was carbonized by successive phenyltrimethoxysilane treatments followed by annealing in inert atmosphere up to 650 C. Emission, excitation, kinetics, and photo-induced bleaching effects were investigated by steady state and time-resolved photoluminescence spectroscopies. The local chemistry was also studied by infrared transmission spectroscopy. Strong ultraviolet and visible photoluminescence was observed in the samples after the chemical treatments/modifications and thermal annealing. It has been shown that ultraviolet photoluminescence in chemically modified fumed silica is associated with phenyl groups, while near ultraviolet and visible emission in annealed samples originated from inorganic pyrolytic carbon precipitates dispersed in the silica host matrix. Two types of emission bands were identified as a function of the annealing temperature: one is in the near UV and the other is in the visible range. Based on the emission/excitation analysis of these two bands, as well as on correlations with the synthesis conditions, a structural-energy concept of light-emitting centers has been proposed. According to this model, the light-emitting centers are associated with carbon clusters that can be bonded or adsorbed on the silica surface. This has been validated by a detailed (S)TEM-electron energy-loss spectroscopy study, confirming the inhomogeneous distribution of nanoscale carbon precipitates at the surface of the silica nanoparticles. These carbon precipitates are mostly amorphous although they possess some degree of graphitization and local order. Finally, the fraction of sp 2 carbon in these nanoclusters has been estimated to be close to 80%. Published by AIP Publishing. https://doi.

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Section: Pl Emissionsupporting

confidence: 62%

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Vasin

Kysil

Lajaunie

et al. 2018

Journal of Applied Physics

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“…The ability of these conjugated polymers to amplify their sensitivity on fluorescence responses is attributed to the efficient electronic delocalization and rapid transport of excitons along the π‐ conjugated backbone. Much research has been done on polyureas due to their outstanding thermal and mechanical properties 3–9. However, to our knowledge, fabrication of solid‐state electrofluorescent devices (EFD) using PU based materials has not been examined and reported.…”

Section: Introductionmentioning

confidence: 99%

“…Much research has been done on polyureas due to their outstanding thermal and mechanical properties. [3][4][5][6][7][8][9] However, to our knowledge, fabrication of solid-state electrofluorescent devices (EFD) using PU based materials has not been examined and reported. Electrofluorescent (EF) materials display a reversible optical change in the fluorescence resulting from electrochemical oxidation or reduction.…”

mentioning

confidence: 99%

Electrochemical fluorescence switching properties of conjugated polymers composed of triphenylamine, fluorene, and cyclic urea moieties

Kuo

Lin

Leung

2012

J. Polym. Sci. A Polym. Chem.

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The study of the electrochemical fluorescence switching properties of the conjugated copolymers containing fluorene, triphenylamine, and 1,3‐diphenylimidazolidin‐2‐one moieties is reported. The polymers show high fluorescence quantum yields, excellent thermal stability, and good solubility in polar organic solvents. While the polymer emits blue light under UV irradiation, the fluorescence intensity is quenched upon electrochemical oxidation. The fluorescent behavior can be reversibly switched between nonfluorescent (oxidized) state and strong fluorescence (neutral) state with a high contrast ratio (If/If0) of 16.3. The role of the electrochemical oxidation of the triphenylamine moieties is to generate the corresponding radical cations that lead to fluorescence quenching in the solid matrix. © 2012 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym Chem, 2012

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“…As previously indicated by polymeric systems based on other types of photoactive units, [7][8][9][10] properties of molecular DA compounds cannot be simply extrapolated to polymeric properties. As evidenced by the comparison with the donor polymers 1D and 2D, the presence of both an electron donor and an electron acceptor is essential herein.…”

Section: Resultsmentioning

confidence: 99%

“…7,8 Among these are transport of excitation energy 9 and excimer formation. 7,10 Moreover, electron donating and accepting groups have the tendency to interact intermolecularly in the ground state, resulting in the formation of charge-transfer complexes. 11,12 Formation of these complexes may not only affect the behavior of the DA chromophores, but also the properties of the material as a whole.…”

Section: Introductionmentioning

confidence: 99%

Charge transfer interactions in polyesters with a donor‐(σ‐bridge)‐acceptor moiety in the repeating unit

Oosterbaan

Kaats-Richters

Jenneskens

et al. 2004

J. Polym. Sci. A Polym. Chem.

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Two high molecular weight linear polyesters were investigated to gain insight in how the photophysics of electron donor-(-spacer)-electron acceptor (DA) compounds are affected by incorporation into a polymer. They were prepared by condensation of either adipoyl or sebacoyl chloride with a diol that was functionalized with an N,N-dialkylaniline donor, a cyclohexyl type -spacer, and a 1,1-dicyanovinyl acceptor. The solubility, which is very low, and the thermal properties of the polyesters are dictated by physical crosslinking as a consequence of interchain donor-acceptor interactions. Charge transfer (CT) absorption and emission are observed, which involve CT between DA moieties of different chains rather than CT processes within a single DA unit. As a result, the photophysics of the DA units in the polyesters differs strongly from that of similar DA compounds in solution. Upon swelling the polymers with THF, the CT fluorescence disappears partly. Analogous polymers containing only an N,N-dialkylaniline donor display dual fluorescence; one band reflects local emission, while the other is attributed to excimer emission.

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Photoluminescence and excimer emission of functional groups in light‐emitting polymers

Cited by 16 publications

References 15 publications

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Electrochemical fluorescence switching properties of conjugated polymers composed of triphenylamine, fluorene, and cyclic urea moieties

Charge transfer interactions in polyesters with a donor‐(σ‐bridge)‐acceptor moiety in the repeating unit

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