Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers

Özel, İlkem Özge; Özel, Tuncay; Demir, Hilmi Volkan; Tuncel, Dönüş

doi:10.1364/oe.18.000670

Cited by 26 publications

(29 citation statements)

References 30 publications

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“…These problems mainly arise from the changes in the polymer morphology upon film casting, which affects the inter and intrachain interactions. To decrease these interactions and consequently, achieve higher QYs in solid films, various approaches have been adopted including the utilization of nonradiative energy transfer to light‐emitting polymers and the incorporation of the polymers into inorganic nanoparticles . Alternatively, chemical entities such as dendrones have been attached to the polymer backbone in order to weaken the π–π stacking .…”

Section: Introductionmentioning

confidence: 99%

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Erdem

Idris

Demir

et al. 2017

Macro Materials & Eng

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they pose significantly lower risks to environment and health compared to other optical materials such as cadmiumbased quantum dots [10] and lead-based perovskites. [11] Despite the potential of conjugated polymers, a decrease in the fluorescence quantum yield (QY) and a low emission stability in their solid state turn out to be an important bottleneck. These problems mainly arise from the changes in the polymer morphology upon film casting, which affects the inter and intrachain interactions. To decrease these interactions and consequently, achieve higher QYs in solid films, various approaches have been adopted including the utilization of nonradiative energy transfer to light-emitting polymers [12,13] and the incorporation of the polymers into inorganic nanoparticles. [14][15][16] Alternatively, chemical entities such as dendrones have been attached to the polymer backbone in order to weaken the π-π stacking.[17] Insulation of the conjugated polymer backbones via rotaxanation, which can be considered as threading the polymer chain using a macrocyclic ring, also steps forward as a promising solution. [18][19][20] In the literature, cyclodextrins and cucurbit[n]urils (CB[n]) have been shown to successfully isolate the polymer backbone leading to enhanced fluorescence QY. [21][22][23][24][25][26] For instance, our group has recently demonstrated fourfold increase in the fluorescence QY of poly(9,9′-bis(6″-(N,N,N-trimethylammonium)hexyl)fluorene-alt-co-thiophenelene) accompanied by blue-shifted fluorescence spectrum and prolonged fluorescence lifetime after threading with CB7. [27] Despite the improvements in the QY of polyrotaxane solutions, their solid films still suffered from decreased fluorescence QY. Therefore, a solution to maintain the fluorescence QY is of significant importance for their use in solid-state lighting.A possible solution to this problem might come from the research on the colloidal quantum dots, which similarly suffered from decreasing QYs in their solid films. Otto et al. [28] showed that the quantum dots in water can be successfully incorporated into crystalline salt matrices. Later, this approach was shown to improve the fluorescence QY, [29] and emission stability. [30,31] Moreover, this method was also extended to nonionic crystals including sucrose [32] and anthracene [33] and to quantum dots in nonpolar solvents [30,34] and applied in lightemitting diodes (LEDs) [31] and sensors. [35] Recently, our group has evaluated the potential of this technique by incorporating π-Conjugated Polyrotaaxanes π-Conjugated polymers suffer from low quantum yields (QYs) due to chainchain interactions. Furthermore, their emission in solid films is significantly quenched due to aggregation leading further decrease in QY. These are the two main issues of these materials hampering their widespread use in optoelectronic devices. To address these issues, here the backbone of poly(9,9′-bis (6″-(N,N,N-trimethylammonium)hexyl)fluorene-alt-co-thiophenelene) is isolated by threading with cucurbit[7]uril (CB7). Su...

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Section: Introductionmentioning

confidence: 99%

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Erdem

Idris

Demir

et al. 2017

Macro Materials & Eng

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“…Then, the reaction mixture was subjected to 3 freeze−thaw− pump cycles to remove oxygen completely. A catalytic amount of Pd(OAc) 2 Nanoparticle Preparation. For preparation of nanoparticles of oligomer, a stock solution of oligomer in THF (10 mg/mL) was prepared before dilution with THF to get different concentrations.…”

Section: ■ Introductionmentioning

confidence: 99%

Red Emitting, Cucurbituril-Capped, pH-Responsive Conjugated Oligomer-Based Nanoparticles for Drug Delivery and Cellular Imaging

et al. 2014

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Here we report the synthesis of nanoparticles based on a conjugated oligomer which is synthesized through Heckcoupling of divinylfluorene and dibromobenzothiodiazole monomers. These water dispersible nanoparticles emit in the region of red tailing to the near-infrared region of the spectrum with high fluorescent quantum yield and brightness. The nanoparticles were found to be stable in water for a prolonged time without forming any aggregates and could carry camptothecin, an anticancer drug with high loading efficiency. MTT cell viability studies performed with breast cancer cell lines showed that halfmaximal inhibitory concentration (IC 50 ) values of nanoparticles for MCF7 and MDA-MB-231 were 44.7 μM and 24.8 μM, respectively. In order to further decrease the cytotoxicity and increase the stability of nanoparticles, amine groups were disguised by capping with cucurbit [7]uril (CB7). Drug release studies showed that drugs were released at low pH (at 5.0) faster than physiological pH (7.4) confirming the pH-responsive nature of the nanoparticles. On the other hand, CB7-capped drug-loaded nanoparticles regulated the release rate by providing slower release at pH 7.4 than the nanoparticles in the absence of CB7s. IC 50 values for camptothecin in the presence of nanoparticles with or without CB7 were significantly reduced in MCF7 and MDA-MB-231 cells. ■ INTRODUCTIONConjugated polymer nanoparticles (CPNs) are highly appealing for various advanced applications such as in vivo imaging, cell labeling, and delivery of therapeutic agents, as well as nanophotonics, owing to their high quantum yields and molar absorptivity, tunable properties, easy functionalization, photostability, and so forth. 1−7 To date, the use of CPNs has been demonstrated successfully in cell imaging, oxygen sensing, drug delivery, and nucleic acid delivery. 8−16 When these nanostructures are judiciously designed, they can be utilized in theranostic applications by combining more than one functionality to deliver therapeutic and imaging agents. 17−21 For the controlled delivery of therapeutic agents to the targets the nanoparticles could also include responsive groups that will respond to stimuli such as pH, oxidation−reduction, and enzymes. However, in the literature, examples are scarce regarding the multifunctional conjugated polymer nanoparticles (CPNs) and even less with conjugated oligomer-based nanoparticles (CONs). 22,23 Recently, Schenning et al. compared the capabilities of conjugated polymer nanoparticles to selfassembled oligomer-based nanoparticles in terms of their fluorescent quantum yields, stabilities, molar absorptivity, guest-holding, and releasing. 24 They demonstrated that oligomer nanoparticles have higher fluorescent quantum yields and comparable stabilities and molar absorptivity, but they release the guest faster than the conjugated polymer nanoparticles. Thus, this feature should be considered for the further design of oligomer-based nanoparticles for theranostic applications. CONs also offer some useful addi...

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“…13 As a result of these attractive properties, CPNs find use as alternative color convertors, or molecular beacons, in various biotechnology 1,3,4 and optoelectronic applications. 6,9,10,13,14 The emission of color convertors, including CPNs, can be enhanced via the Forster-type nonradiative energy transfer (NRET) (also dubbed as Forster resonance energy transfer, FRET), which basically relies on the exciton−exciton interactions between the donor and acceptor emitters. 15 For example, polymers, 16 organic dyes, 17 inorganic QDs, 18 and epitaxial quantum wells 18,19 have been widely investigated for NRET studies.…”

Section: * S Supporting Informationmentioning

confidence: 99%

Morphology-Dependent Energy Transfer of Polyfluorene Nanoparticles Decorating InGaN/GaN Quantum-Well Nanopillars

et al. 2013

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Conjugated polymer nanoparticles (CPNs), prepared in aqueous dispersion from poly[(9,9-bis{3-bromopropyl}fluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1,3}-thiodiazole)] (PFBT-Br), are incorporated into a nanopillar architecture of InGaN/GaN multiple quantum wells (MQWs) to demonstrate a new organic/inorganic class of nanostructured excitonic model system. This hybrid system enables intimate integration for strong exciton−exciton interactions through nonradiative energy transfer (NRET) between the integrated CPNs and MQW pillars. The NRET of these excitonic systems is systematically investigated at varied temperatures. In these hybrids, InGaN/GaN MQWs serve as the donor of the NRET pair, while immobilized PFBT-Br polymer serves as the acceptor. To understand morphology-dependent NRET, PFBT-Br CPNs coating InGaN/GaN MQWs are made to defold into polymer chains by in situ treatment with a good solvent (THF). The experimental results indicate that NRET is significantly stronger in the case of CPNs compared with their defolded polymer chains. At room temperature, while the NRET efficiency of open polymer chains−nanopillar system is only 10%, PFBT-Br CPNs exhibit a substantially higher NRET efficiency of 33% (preserving the total number of polymer molecules). The NRET efficiency of the nanoparticle systems is observed to be 25% at 250 K, 22% at 200 K, 19% at 150 K, and 15% at 100 K. On the other hand, the defolded polymer chains exhibit significantly lower NRET efficiencies of 17% at 250 K, 16% at 200 K, 11% at 150 K, and 5% at 100 K. This work may potentially open up new opportunities for the hybrid organic/inorganic systems where strong excitonic interactions are desired for light generation, light harvesting, and sensing applications. C onjugated polymer nanoparticles (CPNs) attract significant attention for important applications including bioimaging, 1−3 biosensing, 4,5 and optoelectronics. 6−12 One of the most attractive features of CPNs is the convenient tunability and control of their properties through the choice and functionalization of the polymer and the surface modification of nanoparticles. Furthermore, CPNs exhibit low toxicity, 13 and their mechanical stability can be enhanced through cross-linking.14 Their optical properties arise from the controlled conformational changes of the polymer and their aggregation form rather than the quantum confinement effects, in contrast with inorganic nanoparticles, for example, colloidal semiconductor quantum dots (QDs).13 As a result of these attractive properties, CPNs find use as alternative color convertors, or molecular beacons, in various biotechnology 1,3,4 and optoelectronic applications. 6,9,10,13,14 The emission of color convertors, including CPNs, can be enhanced via the Forster-type nonradiative energy transfer (NRET) (also dubbed as Forster resonance energy transfer, FRET), which basically relies on the exciton−exciton interactions between the donor and acceptor emitters. 15 For example, polymers, 16 organic dyes, 17 inorganic QDs, 18 and epitaxial quan...

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Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers

Cited by 26 publications

References 30 publications

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Red Emitting, Cucurbituril-Capped, pH-Responsive Conjugated Oligomer-Based Nanoparticles for Drug Delivery and Cellular Imaging

Morphology-Dependent Energy Transfer of Polyfluorene Nanoparticles Decorating InGaN/GaN Quantum-Well Nanopillars

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