Enhancing the Photoluminescence Intensity of Conjugated Polycationic Polymers by Using Quantum Dots as Antiaggregation Reagents

Nguyen, Bao Toan; Gautrot, Julien E.; Ji, Chuanyong; Brunner, Pierre-Louis M.; Nguyên, My T.; Zhu, Xiangyu

doi:10.1021/la053399j

Cited by 57 publications

(31 citation statements)

References 41 publications

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“…Among the strategies that have been attempted are the incorporation of bulky substituents, 13 introduction of carbazole copolymer units, 14 the interaction with surfactants, [15][16][17] and most recently interaction with nanoparticle assemblies. 18 An alternative explanation for the increase in the emission quantum yield of conjugated polymers upon interaction with surfactants is that it is not due to the disruption of polymer aggregates but is associated with changes in conformational order. [19][20][21] While it is possible that both factors are involved, the breakup of aggregates is likely to be a precursor of such conformational changes.…”

Section: Introductionmentioning

confidence: 99%

Interplay of Electrostatic and Hydrophobic Effects with Binding of Cationic Gemini Surfactants and a Conjugated Polyanion: Experimental and Molecular Modeling Studies

et al. 2007

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Understanding factors responsible for the fluorescence behavior of conjugated polyelectrolytes and modulation of their behavior are important for their application as functional materials. The interaction between the anionic poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}copolymer (PBS-PFP) and cationic gemini surfactants R,ω-(C m H 2m+1 N + (CH 3 ) 2 ) 2 (CH 2 ) s (Br -) 2 (m-s-m; m ) 12, s ) 2, 3, 5, 6, 10, and 12) has been studied experimentally in aqueous solution. These surfactants are chosen to see whether molecular recognition and self-assembly occurs between the oppositely charged conjugated polyelectrolyte and gemini surfactant when the spacer length on the surfactant is similar to the intercharge separation on the polymer. Without surfactants, PBS-PFP exists as aggregates. These are broken up upon addition of gemini surfactants. However, as anticipated, the behavior strongly depends upon spacer length (s). Fluorescence measurements show three surfactant concentration regimes: At low concentrations (<2 × 10 -6 M) quenching occurs and is most marked with the small spacer 12-2-12; at intermediate concentrations (∼2 × 10 -6 -10 -3 M), fluorescence intensity is constant, with a 12-carbon spacer 12-12-12 showing the strongest fluorescence; above the critical micelle concentration (CMC; ∼10 -3 M) increases in emission intensity are seen in all cases and are largest with the intermediate spacers 12-5-12 and 12-6-12, where the spacer length most closely matches the distance between monomer units on the polymer. With longer spacer length surfactants, surface tension measurements for concentrations below the CMC reveal the presence of polymer-surfactant aggregates at the air-water interface, possibly reflecting increased hydrophobicity. Above the CMC, small-angle neutron scattering experiments for the 12-6-12 system show the presence of spherical aggregates, both for the pure surfactant and for polyelectrolyte/gemini mixtures. Molecular dynamics simulations help rationalize these observations and show that there is a very fine balance between electrostatic and hydrophobic interactions. With the shortest spacer 12-2-12, Coulombic interactions are dominant, while for the longest spacer 12-12-12 the driving force involves hydrophobic interactions. Qualitatively, with the intermediate 12-5-12 and 12-6-12 systems, the optimum balance is observed between Coulombic and hydrophobic interactions, explaining their strong fluorescence enhancement.

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Section: Introductionmentioning

confidence: 99%

Interplay of Electrostatic and Hydrophobic Effects with Binding of Cationic Gemini Surfactants and a Conjugated Polyanion: Experimental and Molecular Modeling Studies

et al. 2007

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“…[8][9][10] In these methods, the design ideas are obstructing the formation of luminophoric aggregates. Recently, it has been proved that the construction of organic compounds with aggregation-induced emission property is a convenient but effective way to obtain outstanding luminogens.…”

Section: -4mentioning

confidence: 99%

A series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes: synthesis, structures and solid-state emission behavior

et al. 2018

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By controlling the number of 4,5,9,10-tetrahydropyrene segments around the tetraarylethene core, a series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes were synthesized and structurally characterized. An aggregation-induced emission (AIE) study indicated that all the compounds are AIE active: they are weak emitters in good solvents but highly emissive in the condensed phase, and hence are potential solidstate emitters. Their optical properties, electrochemical properties and theoretical calculations were investigated, and the results prove that the p-conjugation degree of these compounds increases with the increasing number of 4,5,9,10-tetrahydropyrene units. However, the fluorescence quantum yield in the solid state doesn't increase with increasing p-conjugation. We studied the reason for this by analyzing the crystal structures of some compounds, and proposed that the close degree of molecular packing in the solid state may be responsible for it. Loose packing of tetraarylethenes in the solid state can restrict the rotation of the aromatic rings but cannot constrain other non-radiative pathways efficiently, such as vibration, which leads to the unpredictable emission of the compounds. IntroductionThe design and synthesis of organic materials with efficient solid-state uorescence has attracted extensive attention because the performance of organic photoelectric devices is usually dependent on the solid-state properties of materials. 1-4And most luminogenic molecules, especially those with disclike shapes, normally exhibit quenched emission in the condensed state due to the formation of intermolecular pstacking interactions.5-7 Several strategies have been developed to solve this problem such as designing polymers with dendritic structures and using antiaggregation reagents to modulate aggregation. [8][9][10] In these methods, the design ideas are obstructing the formation of luminophoric aggregates. Recently, it has been proved that the construction of organic compounds with aggregation-induced emission property is a convenient but effective way to obtain outstanding luminogens.11-16 Different from the ordinary organic compounds usually with excellent single-molecule emission in solvents, AIE compounds are weakly emissive in good solvent but they become strong emitters when the condensed phase are formed. 17In aggregates, intramolecular rotation which acts as a nonradiative pathway can be restricted effectively, meanwhile the twisted structure of these compounds can avoid the formation of p-stacking to a certain extent, thus achieving high solid-state emission efficiency. As a representative member of AIE dyes, tetraphenylethene (TPE) has attracted much research attention because it enjoys the advantages such as efficient solid-state emission, facile synthesis and easy functionalization.18-20 In addition, by combing TPE and many kinds of polycyclic aromatic hydrocarbons (PAHs), a large number of novel TPE derivatives have been developed. [21][22][23][24][25][26][27] It has been reported that the uores-c...

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“…Several surfactants have been used for synthesizing CdTe quantum dots in the aqueous phase, namely, thioglycolic acid (TGA) [48][49][50], mercaptopropionic acid (MPA) [47], mercaptosucinnic acid (MSA) [51][52], glutathione (GSH) [53], and cysteine (Cys) [54]. TGA, MPA, and MSA are short stabilizing agents and they are commonly used to fabricate water-dispersible CdTe QDs in a one-pot synthesis.…”

Section: Preparation Of Cdte Quantum Dots In the Aqueous Phasementioning

confidence: 99%

Aqueous phase synthesis of CdTe quantum dots for biophotonics

Yong

Law

Roy

et al. 2010

Journal of Biophotonics

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Over the past few years, CdTe quantum dots have been demonstrated as powerful probes for biophotonics applications. The aqueous phase synthesis technique remains the best approach to make high quality CdTe QDs in a single‐pot process. CdTe QDs prepared directly in the aqueous phase can have quantum yield as high as 80%. In addition, the surface of CdTe QDs prepared using the aqueous phase technique is functionalized with reactive groups that enable them to be directly conjugated with specific ligands for targeted delivery and sensing. In this contribution, we review recent progress in fabricating aqueous CdTe QDs and exploiting their optical properties in novel approaches to biomedical imaging and sensing applications. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Enhancing the Photoluminescence Intensity of Conjugated Polycationic Polymers by Using Quantum Dots as Antiaggregation Reagents

Cited by 57 publications

References 41 publications

Interplay of Electrostatic and Hydrophobic Effects with Binding of Cationic Gemini Surfactants and a Conjugated Polyanion: Experimental and Molecular Modeling Studies

Interplay of Electrostatic and Hydrophobic Effects with Binding of Cationic Gemini Surfactants and a Conjugated Polyanion: Experimental and Molecular Modeling Studies

A series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes: synthesis, structures and solid-state emission behavior

Aqueous phase synthesis of CdTe quantum dots for biophotonics

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