Spectroelectrochemical and electrical characterization of low bandgap polymers

Beyer, R.; Kalaji, M.; Kingscote-Burton, G.; Murphy, P. J.; Pereira, V.M.S.C.; Taylor, David; Williams, Gwion

doi:10.1016/s0379-6779(98)80018-0

Cited by 80 publications

(10 citation statements)

References 16 publications

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“…Acetonitrile from Aldrich was either distilled before use or used as is if the acetonitrile was HPLC grade. Cyclopenta[2,1- b ;3,4- b ‘]dithiophen-4-one, CDT, was synthesized according to procedures previously reported. − All spectroscopic and physical data for CDT were similar to those reported in the literature.…”

Section: Methodsmentioning

confidence: 93%

“…Previous studies of PCDT − by optical spectroscopy and cyclic voltammetry have shown that the potential difference between the threshold for hole injection (p-doping) and electron injection (n-doping) leads to an estimated band gap of ∼1.2 eV. In situ IR spectroscopy reported by Beyer et al confirmed the presence of an electronic absorption band in both states of doping. However, they showed that the intensity of this absorption band for the n-doped state is greatly reduced.…”

Section: Introductionmentioning

confidence: 89%

“…This is in contrast with the data reported by others 12-14 in which PCDT exhibited a large degree of n-doping. Beyer et al have also reported on the electrical properties of PCDT-based diodes. Their results showed that in the solid state, Al/PCDT/Au diodes displayed little or no rectification, although capacitance and loss data showed the strong frequency dispersion characteristic of a Schottky diode.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Physicochemical and Electrochemical Characterization of Polycyclopenta[2,1-b;3,4-b‘]dithiophen-4-one as an Active Electrode for Electrochemical Supercapacitors

et al. 1999

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Poly(cyclopenta [2,1-b;3,4-b′]dithiophen-4-one) (PCDT) has been characterized by several electrochemical and spectroscopic techniques so that it can be used as an active electrode material in electrochemical supercapacitors. This polythiophene derivative was prepared by the electrochemical polymerization of cyclopenta[2,1-b;3,4-b′]dithiophene-4-one (CDT) from a nonaqueous solution (acetonitrile) containing tetraethylammonium tetrafluoroborate. The range of electroactivity of PCDT in nonaqueous media spans at least 2 V. The doping levels measured by cyclic voltammetry and EDAX were found to be 0.19 and 0.14, respectively, for the oxidized-PCDT. Low-frequency capacitance measurements were made by electrochemical impedance spectroscopy to evaluate the film's ability to store charge. Low-frequency capacitances of about ∼70 F/g were found for both the p-and n-doped states. Ionic and electronic resistances were established using both a Randles equivalent circuit and the linear transmission line model to analyze the impedance data of electronically conducting polymers. The film morphology was studied by scanning electron microscopy, and photomicrographs revealed an open and porous structure. X-ray photoelectron spectroscopy was employed to evaluate the electronic properties of the polymer. Negatively charged sulfur atoms were only observed in low content probably due to low negative polaron stability and the sensitivity of the polymer to trace amounts of oxygen and water. Nonetheless, the S 2p σ-species for the n-doped state has clearly been identified in our study as we present here. A conservative estimate of the doping level was found to be ∼0.06. Preliminary galvanostatic charge/ discharge cycling experiments indicated an energy density, E, of about 6 (W h)/kg for the active material with a power density, P, of 1 kW/kg for an 18 s discharge time. These values are above the midterm requirements fixed by the U. S. Department of Energy for electrochemical supercapacitors (E > 5 (W h)/kg and P > 500 W/kg). A discharge capacity decrease was observed during the first 20 cycles but thereafter the discharge capacity remained constant for the next 80 cycles. Additional work is currently under way to improve the stability of the PCDT-based capacitor since this conducting polymer should be very interesting as an active electrode in electrochemical supercapacitors.

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Section: Methodsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Physicochemical and Electrochemical Characterization of Polycyclopenta[2,1-b;3,4-b‘]dithiophen-4-one as an Active Electrode for Electrochemical Supercapacitors

et al. 1999

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“…Among the known low band gap conducting polymers, poly(4-dicyanomethylene-4 H -cyclopenta[2,1- b ; 3,4- b ‘ ]dithiophene) − (poly- 1 ) has one of the lowest band gaps. We have investigated its in situ conductivity as a function of potential and shown that its intrinsic conductivity (∼10 -8 S cm -1 ) corresponds to that prediced from its band gap (0.8 eV) .…”

Section: Introductionmentioning

confidence: 99%

Oxygen-Modified Poly(4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b‘]dithiophene): A Tunable Low Band Gap Polymer

Huang

Pickup

1999

Chem. Mater.

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The reaction of n-doped poly(4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b ‘]dithiophene) with O2 at negative potentials (e.g., −0.60 V) produces changes in the polymer's electrochemistry, electronic spectrum, and conductivity profile that indicate a lowering of its band gap. Cyclic voltammetry of O2-modified films shows increased currents in the voltage region corresponding to the band gap, between the original onsets of n and p doping. The onset of electronic absorption shifts from 0.8 eV to lower energies with increasing reaction time. In situ conductivity measurements show that the intrinsic conductivity increases by as much as a factor of 100 (to ∼10-6 S cm-1), corresponding to a reduction of the band gap to ∼0.2 eV. Thus by controlling the reaction time with O2 the band gap of the polymer can be tuned over the range of <0.2 to 0.8 eV. Raman spectra suggest that electrochemically driven substitution of the polymer with hydroxyl groups at the β-positions of the thiophene rings is responsible for the lowering of the band gap.

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“…3-Bromothiophene ( 1 , 60 g, 0.36 mol) was added into a solution of n -butyllithium (0.36 mol) in THF (120 mL) at −78 °C and a solution of the ethyl formate (13.63 g, 0.184 mol) in THF (60 mL) was added dropwise while maintaining the temperature between −78 and −70 °C [ 17 ]. The mixture was then allowed to warm slowly (over ~1 h) to RT.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Anticancer Activity of Di(3-thienyl)methanol and Di(3-thienyl)methane

et al. 2012

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Di(3-thienyl)methanol (2) and di(3-thienyl)methane (3) have been synthesized and screened against the T98G (brain cancer) cell line. Treatment induced cell death (MTT and macro-colony assay), growth inhibition, cytogenetic damage (micronuclei formation), were studied as cellular response parameters. Treatment with the compounds enhanced growth inhibition and cell death in a concentration dependent manner in both T98G and HEK (normal) cell lines. At higher concentrations (>20 µg/mL) the cytotoxic effects of the compounds were highly significant. The effect on clonogenic capacity and micronuclei formation observed after treatment of cells. Amongst the compounds, compound 2 exhibited potent activity against T98G brain cancer cells. Despite potent in vitro activity, both compounds exhibited less cytotoxicity against normal human HEK cells at all effective concentrations.

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Spectroelectrochemical and electrical characterization of low bandgap polymers

Cited by 80 publications

References 16 publications

Physicochemical and Electrochemical Characterization of Polycyclopenta[2,1-b;3,4-b‘]dithiophen-4-one as an Active Electrode for Electrochemical Supercapacitors

Physicochemical and Electrochemical Characterization of Polycyclopenta[2,1-b;3,4-b‘]dithiophen-4-one as an Active Electrode for Electrochemical Supercapacitors

Oxygen-Modified Poly(4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b‘]dithiophene): A Tunable Low Band Gap Polymer

Synthesis and Anticancer Activity of Di(3-thienyl)methanol and Di(3-thienyl)methane

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