Photovoltaic Response of Ultrathin Films of Retinal Derivatives

Tenorio, Alexandro C.; Silva, A.M.S.; Melo, Celso P. de

doi:10.1002/1521-3951(200207)232:1<50::aid-pssb50>3.0.co;2-q

Cited by 6 publications

(1 citation statement)

References 8 publications

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“…The impedance measurements were performed using a SI 1260 (Solartron Instruments, UK) gain/phase impedance analyzer, operating in the (1–10 7 ) Hz of frequency range. A 100‐mV excitation, with no external polarization, was applied to each sample 38–42. Ten equally spaced points were obtained in logarithmic scale per decade, and the corresponding values of the real and imaginary parts of the impedance ( Z ′ and Z ″, respectively) were processed by means of the Smart software (Solartron Instruments, UK).…”

Section: Methodsmentioning

confidence: 99%

Effect of the lithium cation on the sorption and electrical properties of amphiphilic block copolymers and their composites

Silva

Rieumont

Nogueiras

et al. 2010

J Polym Sci B Polym Phys

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The use of lithium cation in composites of block copolymers [polyethylene-b-polyethylene oxide (PE-b-50%PEO and PE-b-80%PEO)] and their derivatives was tested as a modifier of the vapor sorption and impedance of these complexes. The block copolymer PE-b-80%PEO was modified by oxidation of its hydroxyl end group to both a carboxylic acid group (PE-b-80%PEO)CH 2 COOH and its sodium salt (PE-b-80%PEO)CH 2 COO À Na þ for the purpose of improving its compatibility and performance as a matrix for composites. These modified copolymers were characterized by FTIR, DSC, and mass spectrometry. The sorption of water of these copolymers and their composites with lithium nitrate was also compared, as well as the electrical properties of their composites were measured by electrical impedance spectroscopy. For the composites obtained with PE-b-80%PEO and lithium nitrate, it was found that lithium cation plays an important role increasing the sorption rate, which is maximized for the PE-b-80%PEO þ (21% lithium nitrate) composite. For the copolymers (PE-b-80%PEO)CH 2 COOH and (PE-b-80%PEO)CH 2 COO À Na þ and their composites, the highest sorption rate was observed for salt in the following order: COO À Na þ > COOH > OH. The PE-b-80%PEO þ (21% lithium nitrate) composite behaves as a solid polymeric ionic conductor fitting the Williams-Landel-Ferry equation. However, both (PE-b-80% PEO)CH 2 COOH and (PE-b-80%PEO)CH 2 COO À Na þ þ (21% lithium nitrate) composites fitted the Variable Range Hopping equation, indicating a conductance trend with temperature governed by a thermally activated with energy of 0.482 and 0.524 eV and not by a relaxation process.

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Section: Methodsmentioning

confidence: 99%