Three-Dimensional Electronic Delocalization in Chiral Conjugated Polymers

Zahn, Steffen; Swager, Timothy M.

doi:10.1002/1521-3773(20021115)41:22<4225::aid-anie4225>3.0.co;2-3

Cited by 180 publications

(166 citation statements)

References 2 publications

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“…Therefore initial investigations 22 into fabricating obliquely aligned PPE aggregates were carried out with P14. Chiral side chains were introduced into the repeat unit with the expectation that chirality, coupled with the normal twisting of polymer backbones, will yield self-assembled, ordered aggregates.…”

Section: Aggregatesmentioning

confidence: 99%

Structure—Property relationships for exciton transfer in conjugated polymers

Andrew

Swager

2011

J Polym Sci B Polym Phys

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The ability of conjugated polymers to function as electronic materials is dependent on the efficient transport of excitons along the polymer chain. Generally, the photophysics of the chromophore monomer dictate the excited state behavior of the corresponding conjugated polymers. Different molecular structures are examined to study the role of excited state lifetimes and molecular conformations on energy transfer. The incorporation of rigid, three-dimensional scaffolds, such as iptycenes and cyclophanes, can encourage an oblique packing of the chromophore units of a conjugated polymer, thus allowing the formation of electronically-coupled aggregates that retain high quantum yields of emission. Rigid iptycene scaffolds also act as excellent structural directors that encourage complete solvation of PPEs in a liquid crystal (LC) solvent. LC-PPE mixtures display both an enhanced conformational alignment of polymer chains and extended effective conjugation lengths relative to isotropic solutions, which leads to enhanced energy transfer. Facile exciton migration in poly(p-phenylene ethynylene)s (PPEs) allows energy absorbed over large areas to be funneled into traps created by the binding of analytes, resulting in signal amplification in sensory devices. INTRODUCTION Conjugated polymers (CPs) are useful materials that combine the optoelectronic properties of semiconductors with the mechanical properties and processing advantages of plastics. In general, CPs in their neutral state are wide band-gap semiconductors with direct band gaps. 1 Many CPs have an extremely large absorption cross-section (r % 10 À15 cm 2 ) because the p!p* transition is allowed and the quasi one-dimensional electronic wavefunctions have a high density of states at the band edge. 2 Additionally, a CP can exhibit strong luminescence depending on the system. The luminescence efficiency is primarily related to the delocalization and polarization of the electronic structure of the CP. 1

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Section: Aggregatesmentioning

confidence: 99%

Structure—Property relationships for exciton transfer in conjugated polymers

Andrew

Swager

2011

J Polym Sci B Polym Phys

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“…The fi rst [n]helicenes, [6]pyrrolohelicene (2) and [5]helicene (3), were reported in 1927 and 1933, respectively [22][23][24]. The synthesis of a non-racemic [n]helicene, [6]helicene (1), was fi rst described by Newman and Lednicer in 1956 [25].…”

Section: Helicenesmentioning

confidence: 99%

“…Because the dian- ion of cyclooctatetraene itself is a planar, aromatic compound, the inversion barrier is expected to be lowered to an extent dependent upon the de gree of aromatic character in the central eight-membered ring upon n-doping. This proposition was tested in tetranaphthylene 56 and its corresponding carbodianions 56 2 …”

Section: Barriers For Racemization Ofchiral π-Conjugated Systemsmentioning

confidence: 99%

“…In this context, the inherent three-dimen sional character of chirality and the control of intermolecular interactions asso ciated with diastereomeric recognition provide a versatile handle for the optimiza tion of supramolecular structures, fi lm morphology and liquid crystalline order of π-conjugated polymers and oligomers in three dimensions [1][2][3][4][5]. These inher ently achiral properties have an impact on optoelectronic coupling, which may affect the fabrication of light-emitting diodes, fi eld effect transistors, photodiodes, photovoltaic cells, fl uorescent sensors and other devices [2,3,5]. Another aspect of the design involves optimization of chiral counterparts of properties in optics (circular polarization of light), electronics (chiral transport of charge carriers), etc.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Novel Chiral Conjugated Materials

Rajca

Miyasaka

2006

Functional Organic Materials

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“…[3][4][5] Recently, self-assemblies of oligo(p-phenylene-ethynylene) derivatives as rigid p-conjugated molecules have attracted a great deal of attention. [6][7][8][9][10] Controlled ordering of the self-assembled architectures requires skillful design of molecular constituents. Successful examples are spherical to tubular or cylindrical assemblies formed by attaching chiral handles 11,5,[12][13][14][15][16] or by the sergeant-and-soldiers [17][18][19][20] coassembly approach.…”

Section: Introductionmentioning

confidence: 99%

Quantum yield and morphology control of BODIPY-based supramolecular self-assembly with a chiral polymer inhibitor

Nagai

Kokado

Miyake

et al. 2010

Polym J

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Chiral rod-coil-type organoboron polymers S-poly and R-poly were prepared from the palladium-catalyzed SonogashiraHagihara coupling reaction of boron dipyrromethene-based monomer 1, which has bisiodophenyl and decyl groups with S-or R-6,6¢-diethynyl-2,2¢-dioctyloxy-1,1¢-binaphthyls (S-2 and R-2), in a solvent mixture (tetrahydrofuran (THF)/triethylamine¼2/1 (v/v)) at 40 1C for 24 h. The obtained polymers were characterized by hydrogen-1 nuclear magnetic resonance (NMR), carbon-13 NMR ( 13 C NMR), boron-11 NMR ( 11 B NMR) and infrared spectroscopy. The scanning electron microscopy (SEM) analysis of each chiral polymer clearly revealed micrometer-sized fiber-like structures formed by the aggregation of each particle, as we expected. Next, we examined the relationship between the ratio of photoluminescence (PL) intensity (I/I 0 ¼R-poly/S-poly) and particle diameter, measured by dynamic light scattering analysis, versus the R-poly content of the mixed polymer of S-poly and R-poly in THF, which varied from 0 to 100%. As a result, the PL intensity and diameter showed maximum and minimum (about 32 nm) values, respectively, at 70% content, depending on the differences between both the molecular weights and absolute values of the chiral characters. These findings indicate that the PL intensity of S-poly influences morphology change by adding R-poly; that is, R-poly acts as an inhibitor toward the aggregation of S-poly. Furthermore, the SEM image of the mixed polymer (S-poly/R-poly¼30/70) showed complete particle structures from nano-to micrometer sizes, which were roughly 480 nm to 1.19 lm in diameter, and the U F of the mixed polymer was significantly high (0.98).

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Three-Dimensional Electronic Delocalization in Chiral Conjugated Polymers

Cited by 180 publications

References 2 publications

Structure—Property relationships for exciton transfer in conjugated polymers

Structure—Property relationships for exciton transfer in conjugated polymers

Synthesis and Characterization of Novel Chiral Conjugated Materials

Quantum yield and morphology control of BODIPY-based supramolecular self-assembly with a chiral polymer inhibitor

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