Synthetic studies of extraordinarily long oligothiophenes

Otsubo, Tetsuo; Aso, Yoshio; Takimiya, Kazuo; Nakanishi, Hiizu; Sumi, Naoto

doi:10.1016/s0379-6779(02)00376-4

Cited by 13 publications

(7 citation statements)

References 13 publications

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“…57 The redshift proportional to the reciprocal number of repeat units given by our TD-DFT calculations (see Figure S4) has also been observed and predicted for other similar polythiophene systems. 10,15,17,58,59 In our calculations, deviation from linearity appears for n = 20, which is consistent with previously reported experimental values on very similar systems 60,61 and could be related to the loss of planarity clearly apparent in 20T. Extrapolation of the calculated transitions energies to an infinite chain length leads to a bandgap close to 2.1 eV, which is in perfect agreement with the usual values found in the literature.…”

Section: ■ Results and Discussionsupporting

confidence: 92%

Revisiting the Vibrational and Optical Properties of P3HT: A Combined Experimental and Theoretical Study

et al. 2018

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We demonstrate that DFT-based calculations can provide straightforward means to analyze the effect of aggregation on the optical properties of regioregular P3HT oligomers of different lengths (up to 20-mers) and of bioligomers of 8-mers in two different conformations. Our conclusions substantially differ from those obtained previously by applying the exciton model. Indeed, analysis of Huang-Rhys factors has evidenced that two vibrational modes, a collective mode and an effective mode, are combined in the vibronic structure of the absorption spectrum of oligothiophene. Computed spectra match perfectly their experimental counterparts provided we consider that the oligomer and at least the five lowest excited states of bioligomers behave as absorbers, and that both oligomer and bioligomer contribute to the emission spectra. Study of the nature of the Franck-Condon excitation and optimization of the five lowest excited singlet states indicate that high (hot) excited states of the bioligomer may play an important role in the initiation of charge separation and highlight the importance to take into account the relaxation processes in the theoretical modeling of emission properties.

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Section: ■ Results and Discussionsupporting

confidence: 92%

Revisiting the Vibrational and Optical Properties of P3HT: A Combined Experimental and Theoretical Study

et al. 2018

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“…The number-average degree of polymerization () of P3HT- 1 was ca . 29 repeat units, a value low enough to facilitate chain-end chemistry but also low enough to perhaps invoke chain-confinement effects and limit inter-P3HT electronic interactions. ,,− P3HT- 2 had a higher molecular weight (DP n ≈ 36) and was expected to form greater intermacromolecular interactions.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Donor−Acceptor Multiblock Copolymers Incorporating Fullerene Backbone Repeat Units

et al. 2010

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The synthesis of the first example of a block copolymer based on a polymer using fullerene as a backbone repeat subunit is demonstrated. A facile route incorporating the electron acceptor and high fullerene content polymer, poly{(1,4-fullerene)-alt-[1,4-dimethylene-2,5-bis(cyclohexylmethyl ether)phenylene]} (PFDP), with the archetypal electron donor, poly(3-hexylthiophene) (P3HT), into a multiblock copolymer (MBC) structure is presented. R,ω-Bromomethyl-PFDP was prepared by atom-transfer radical addition polymerization (ATRAP) and then reacted with R,ω-phenol-P3HT via a Williamson condensation to yield the MBCs. The lengths of the electron-acceptor and donor polymer blocks could be selected so that the resulting solid state domains were of a size appropriate to organic solar cells. Also it was found that the MBCs gave a wide range of macro-structures, from micelles to well-defined wires, depending on the preparation conditions.

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“…Interestingly, this series displays only a moderate red shift as the length of the conjugated system increases, as judged by ultra-violet and fluorescence spectroscopy (Table ). While the UV maxima exhibit a small but steady shift to the red with increasing molecule length, the red-shifting trend in emission appears to plateau after 1c ; furthermore, the sizable and relatively constant Stokes shift of ∼130 nm is larger than that observed for thiophene systems of similar length but different alkylation pattern . This is likely due to the sensitivity of conjugation length in the ground state to steric environment.…”

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confidence: 84%

Oligothiophene Isocyanides for Platinum-Based Molecular Electronic Applications

2004

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Understanding molecular orientation on a metal surface is key to designing molecular electronic device junctions. Though platinum device electrodes are of particular interest as a more stable alternative to the often used gold electrodes, the chemisorption of conducting molecules onto platinum surfaces has not been thoroughly studied. We present herein the first detailed study of the ability and manner in which soluble oligothiophene isocyanides, of lengths ranging from 2 to 7 nm, chemisorb onto platinum surfaces and nanoparticles. It was found that these oligothiophene isocyanides stand at a 41 degrees angle from the platinum surface normal, suggesting their applicability in molecule-bridged platinum electrode devices.

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Synthetic studies of extraordinarily long oligothiophenes

Cited by 13 publications

References 13 publications

Revisiting the Vibrational and Optical Properties of P3HT: A Combined Experimental and Theoretical Study

Revisiting the Vibrational and Optical Properties of P3HT: A Combined Experimental and Theoretical Study

Synthesis of Donor−Acceptor Multiblock Copolymers Incorporating Fullerene Backbone Repeat Units

Oligothiophene Isocyanides for Platinum-Based Molecular Electronic Applications

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