Ultrathin polyelectrolyte multilayers: in situ ESR/UV-Vis-NIR spectroelectrochemical study of charge carriers formed under oxidation

Rapta, Peter; Lukkari, Jukka; Tarábek, Ján; Salomäki, Mikko; Jussila, Matti; Yohannes, Gebrenegus; Riekkola, Marja‐Liisa; Kankare, Jouko; Dunsch, Lothar

doi:10.1039/b308891j

Cited by 35 publications

(25 citation statements)

References 52 publications

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“…As the OCP decayed from its initial value of 4.2 V for CRP‐6, the UV/Vis absorption intensity at 384 nm increased from 0.36 to 0.43 during the first 1000 s and reached a plateau thereafter (Figure a, c); this band is attributed to the undoped form of polythiophene, and indicates de‐doping of the backbone during OCP decay. Similarly, the intensity of the polythiophene cation (polarons) at 721 nm also increased from 0.49 to 0.58, which suggests conversion of bications (bipolarons) (>1100 nm) to cations (Figure d), further supporting reduction of the polythiophene backbone. In comparison, P3BT showed a similar trend (Figure b), with more pronounced polymer cation conversion as compared to CRP‐6.…”

Section: Figurementioning

confidence: 82%

Unusual Internal Electron Transfer in Conjugated Radical Polymers

Gore

Wang

et al. 2017

Angewandte Chemie

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Nitroxide‐containing organic radical polymers (ORPs) have captured attention for their high power and fast redox kinetics. Yet a major challenge is the polymer's aliphatic backbone, resulting in a low electronic conductivity. Recent attempts that replace the aliphatic backbone with a conjugated one have not met with success. The reason for this is not understood until now. We examine a family of polythiophenes bearing nitroxide radical groups, showing that while both species are electrochemically active, there exists an internal electron transfer mechanism that interferes with stabilization of the polymer's fully oxidized form. This finding directs the future design of conjugated radical polymers in energy storage and electronics, where careful attention to the redox potential of the backbone relative to the organic radical species is needed.

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Section: Figurementioning

confidence: 82%

Unusual Internal Electron Transfer in Conjugated Radical Polymers

Gore

Wang

et al. 2017

Angewandte Chemie

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“…The structures corresponding to polarons and polaron pairs exhibited similar optical spectra and only a small shift in wavelengths was found [32]. It should be noted that the formation of interchain π-dimers is strongly suppressed in dilute solutions.…”

Section: Resultsmentioning

confidence: 99%

“…As already extensively discussed in [ 32 ] concerning the redox properties of self-assembled polyelectrolyte multilayers, consisting of well-defined water-soluble electronically conducting poly-3-(30-thienyloxy)propyltriethylammonium, the spinless doubly charged species can be explained by the interchain or intrachain coupling of two polarons, leading to the formation of dimeric structures between the neighboring chains or to the formation of two polaronic structures in a singlet ground state within the chain [ 33 ]. The structures corresponding to polarons and polaron pairs exhibited similar optical spectra and only a small shift in wavelengths was found [ 32 ]. It should be noted that the formation of interchain π-dimers is strongly suppressed in dilute solutions.…”

Section: Resultsmentioning

confidence: 99%

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

Jiang¹,

Mazzanti

Parker³

et al. 2015

Beilstein J. Org. Chem.

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SummaryA selection of cyclic and acyclic acetylenic scaffolds bearing two tetrathiafulvalene (TTF) units was prepared by different metal-catalyzed coupling reactions. The bridge separating the two TTF units was systematically changed from linearly conjugated ethyne, butadiyne and tetraethynylethene (trans-substituted) units to a cross-conjugated tetraethynylethene unit, placed in either acyclic or cyclic arrangements. The cyclic structures correspond to so-called radiaannulenes having both endo- and exocyclic double bonds. Interactions between two redox-active TTF units in these molecules were investigated by cyclic voltammetry, UV–vis–NIR and EPR absorption spectroscopical methods of the electrochemically generated oxidized species. The electron-accepting properties of the acetylenic cores were also investigated electrochemically.

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“…The observed shift of the optical band at 930 nm to 860 nm indicates formation of doubly charged (bipolaronic) states within the film at higher potentials. [29] In further experiments the thus-prepared film was rigorously washed with monomer-free electrolyte, and the spectroelectrochemical experiment was performed with polymer film (1) n on ITO in 0.2 m TBAPF 6 /acetonitrile electrolyte. In the first stage of film oxidation optical bands around 675 and 1000 nm increase (Figure 8 a) with a simultaneous decrease of the initial polymer/oligomer band at 490 nm.…”

Section: Spectroelectrochemistrymentioning

confidence: 99%

On the Electrochemistry and Spectroelectrochemistry of Small Model Star‐Shaped Compounds: 1,3,5‐Triaryl‐1‐Methoxybenzenes and 2,4,6‐Triaryl‐1,3,5‐Trimethoxybenzenes

et al. 2012

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Model structures of 1,3,5-triarylbenzenes with a substituted benzene core linked to thienyl or 3,4-ethylenedioxythienyl (EDOT) terminal groups are studied by electrochemical and in situ ESR/UV/Vis/NIR spectroelectrochemical techniques. Oxidative polymerization of the monomers results in C-C coupling of the thiophene moieties in the 5-position, forming dimeric structures with bithiophene linkers as the first step. Both the doubly charged protonated dimer and the new dimer formed after proton release are studied in detail for 2,4,6-tris[2-(3,4-ethylenedioxythienyl)]-1-methoxybenzene. Quite high stability of the doubly charged σ dimer formed on oxidation with unusual redox behavior at the electrode is observed. Density functional calculations of the molecular structure as well as spectroscopic and electronic properties of charged states in 1,3,5-triarylbenzene derivatives in the monomeric, dimeric, and oligomeric form are presented. The complex spectroelectrochemical response of a thin solid film formed on the electrode surface upon potentiodynamic polymerization indicates the existence of different charge states of oligomeric structures within the solid matrix.

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Ultrathin polyelectrolyte multilayers: in situ ESR/UV-Vis-NIR spectroelectrochemical study of charge carriers formed under oxidation

Cited by 35 publications

References 52 publications

Unusual Internal Electron Transfer in Conjugated Radical Polymers

Unusual Internal Electron Transfer in Conjugated Radical Polymers

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

On the Electrochemistry and Spectroelectrochemistry of Small Model Star‐Shaped Compounds: 1,3,5‐Triaryl‐1‐Methoxybenzenes and 2,4,6‐Triaryl‐1,3,5‐Trimethoxybenzenes

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