Structural property relationships in conjugated polymers

Lynch, Patrick; O’Neill, Luke A.J.; Whelan, John; McNamara, Mary; Byrne, Hugh J.

doi:10.1117/12.598779

Cited by 5 publications

(5 citation statements)

References 24 publications

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“…3,6‐carbazole was also readily available and was found to be very beneficial for these structure‐property relationship studies. The phenyl monomer ( 2 ) has symmetrical ethylhexyloxy substituents that give this monomer four unique attributes: (1) branched chains for improved solubility; (2) increased emissive efficiency due to increased chain separation (solid state); (3) para ‐positioning of the substituents giving rise to red shifting of the fluorescence; and (4) and increased electron density on the phenyl ring provided by the alkoxy group . Electron donating groups, like alkoxy groups, are known to increase electron density in a polymer main chain, raising the HOMO energy level .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure-optoelectronic property relationships of a series of PPV and SFTV derived polymers

David

Arasho

Sun

2015

J. Polym. Sci. Part A: Polym. Chem.

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Engineering of the highest occupied molecular orbital and lowest unoccupied molecular orbitals through synthetic chemical structural modification has been the most widely used method to tuning optoelectronic properties in conjugated polymers. The electronic, thermal, optical, and physical properties can be tuned and exploited for optimization of optoelectronic devices. Through copolymerization of donor and acceptor type conjugated monomers, the frontier orbitals of four polymers were tailored. Through this synthetic engineering, the relationship between structural features, frontier orbital tailoring, and changes in optoelectronic and physical properties are discussed. Spectroscopic, thermal, and electronic analysis of the polymers indicated that polymers containing carbazole monomer moieties gave overall improved optoelectronic properties, but higher band gaps (2.61 and 2.18 eV) in comparison to their phenyl-based counterparts. This result is attributed to the higher electron density of the carbazole than the terephthaldicarboxaldehyde, and the possible deviation from planarity in the polymer main chain due to possible steric hindrance of the branched substituents.

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Section: Resultsmentioning

confidence: 99%

Synthesis and structure-optoelectronic property relationships of a series of PPV and SFTV derived polymers

David

Arasho

Sun

2015

J. Polym. Sci. Part A: Polym. Chem.

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“…With these relationships established for both the phenyl and acene in both IR and Raman spectroscopy and the confirmation of the decrease in ir vibrational activity in the modelled oligomers the next stage was to synthesis novel polymer systems which incorporated the knowledge gained for the exploration of the well-defined oligomer systems. The polymers were synthesised by P. Lynch et al [30] and can be seen in figure 5. The polymers were investigated using fluorescence and uv/visible spectroscopy which again showed a well-defined progression in electronic structure aswell as Stokes shift [30].…”

Section: Resultsmentioning

confidence: 99%

“…The polymers were synthesised by P. Lynch et al [30] and can be seen in figure 5. The polymers were investigated using fluorescence and uv/visible spectroscopy which again showed a well-defined progression in electronic structure aswell as Stokes shift [30]. The results shown below are of the Raman spectroscopic characterisation which will be discussed in terms of there structure property relationships to attempt to reconcile them with the already examined oligomers structures.…”

Section: Resultsmentioning

confidence: 99%

Relationships for electron-vibrational coupling in conjugated π organic systems

O’Neill¹,

Lynch²,

McNamara³

et al. 2005

SPIE Proceedings

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A series of π conjugated systems were studied by absorption, photoluminescence and vibrational spectroscopy. As is common for these systems, a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transition energies, it was observed that the Stokes shift also exhibited a well-defined relationship with increasing conjugation length, implying a correlation between the electron-vibrational coupling and chain length. This correlation is further examined using Raman spectroscopy, whereby the integrated Raman scattering is seen to behave superlinearly with chain length. There is a clear indication that the vibrational activity and thus nonradiative decay processes are controllable through molecular structure. The correlations between the Stokes energies and the vibrational structure are also observed in a selection of PPV based polymers and a clear trend of increasing luminescence efficiency with decreasing vibrational activity and Stokes shift is observable. The implications of such structure property relationships in terms of materials design are discussed.

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“…Rissler's 2004 work on the effective conjugation length of π-conjugated systems discusses in detail the dependence of excitation energy and electron−hole distances on polymer size (i.e., number of repeat units). 430 Literature suggests that the electronic properties saturate at about 10−20 double bonds along the conjugation pathway, 431 but longer lengths (up to 24− 30 double bonds or even more) may be necessary to mitigate spurious end effects on the electronic and optical properties. 432 The lower bound of the number of repeat units to use in simulation is thus evident; chains should be sufficiently longer than the effective molecular weight to appropriately capture the semiflexible chain dynamics of OSC polymers.…”

Section: Simulations Of Oscmentioning

confidence: 99%

Computational Approaches for Organic Semiconductors: From Chemical and Physical Understanding to Predicting New Materials

2023

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While a complete understanding of organic semiconductor (OSC) design principles remains elusive, computational methods�ranging from techniques based in classical and quantum mechanics to more recent data-enabled models�can complement experimental observations and provide deep physicochemical insights into OSC structure− processing−property relationships, offering new capabilities for in silico OSC discovery and design. In this Review, we trace the evolution of these computational methods and their application to OSCs, beginning with early quantum-chemical methods to investigate resonance in benzene and building to recent machine-learning (ML) techniques and their application to ever more sophisticated OSC scientific and engineering challenges. Along the way, we highlight the limitations of the methods and how sophisticated physical and mathematical frameworks have been created to overcome those limitations. We illustrate applications of these methods to a range of specific challenges in OSCs derived from π-conjugated polymers and molecules, including predicting charge-carrier transport, modeling chain conformations and bulk morphology, estimating thermomechanical properties, and describing phonons and thermal transport, to name a few. Through these examples, we demonstrate how advances in computational methods accelerate the deployment of OSCsin wide-ranging technologies, such as organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), organic thermoelectrics, organic batteries, and organic (bio)sensors. We conclude by providing an outlook for the future development of computational techniques to discover and assess the properties of highperforming OSCs with greater accuracy.

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Structural property relationships in conjugated polymers

Cited by 5 publications

References 24 publications

Synthesis and structure-optoelectronic property relationships of a series of PPV and SFTV derived polymers

Synthesis and structure-optoelectronic property relationships of a series of PPV and SFTV derived polymers

Relationships for electron-vibrational coupling in conjugated π organic systems

Computational Approaches for Organic Semiconductors: From Chemical and Physical Understanding to Predicting New Materials

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