AC conductivity and dielectric measurements of metal-free phthalocyanine thin films dispersed in polycarbonate

Riad, A.S.; Korayem, M T; Abdel‐Malik, T. G.

doi:10.1016/s0921-4526(99)00129-5

Cited by 70 publications

(23 citation statements)

References 30 publications

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“…Figure 11 shows the temperature dependence of the relaxation time τ as ln τ vs. 1000/T according to the following equation [35]:…”

Section: Frequency and Temperature Dependencementioning

confidence: 99%

“…SeTe alloys are widely used for various applications in many elds as optical recording media and electrographical applications. The composition Se 85 Te 15 has been studied by several authors [35] because of its ease of fabrication in the bulk a thin lm forms. The addition of impurities like Bi is particularly of much interest as it has produced a change in optical, electrical and thermal properties of SeTe chalcogenide glasses [68].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films

Atyia

2014

Acta Phys. Pol. A

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The eect of annealing at dierent temperatures between Tg and Tc on the AC conductivity and dielectric properties was studied for Se70Te15Bi15 lms grown by thermal evaporation technique. The lms were characterized by X-ray diraction, dierential thermal analysis, and energy dispersive X-ray spectroscopy. X-ray diraction analysis shows the occurrence of amorphous to polycrystalline transformation for lms annealed at annealing temperature Ta ≥ 473 K. AC conductivity σAC(ω) was studied as a function of Ta, frequencies (0.1100 kHz) and working temperatures (303393 K). It was found that σAC(ω) obeyed Aω s law. According to the values of s and its temperature dependence, the AC conduction mechanism was determined in terms of the correlated barrier hopping and quantum mechanical tunneling models for the as deposited and annealed lms, respectively. The DC and AC activation energies were determined as a function of Ta. Values of dielectric constant ε1 and dielectric loss ε2 were found to increase with increasing Ta. A Debye-like relaxation of dielectric behavior was observed for polycrystalline lms, and was found to be a thermally activated process.

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“…Figure 11 shows the temperature dependence of the relaxation time τ as ln τ vs. 1000/T according to the following equation [35]:…”

Section: Frequency and Temperature Dependencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films

Atyia

2014

Acta Phys. Pol. A

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“…All calculations are done automatically and the output signal is presented in terms of capacitance, C, and resistance, R, of the sample as a function of the frequency. Namely, calculations of the dielectric properties of the measured samples placed in the parallel plate capacitor, a circuit where C is in a parallel configuration with R is assumed [41,84,85]. SEM micrographs were taken using either an FE SEM LEO 982 (EMSL, Richland, WA) or SEM LEO-EVO 50 [41].…”

Section: Conductivity Measurements Of Pclc / Dopant Compositionsmentioning

confidence: 99%

The role of conductive dopants in polymer cholesteric liquid crystals

Petkoska¹

2014

Maced. J. Chem. Chem. Eng.

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A variety of conductive dopants were used to modify the electric properties of polymer cholesteric liquid crystals. Different types of carbon blacks and carbon nanotubes, as well as metallic particles were used as conductive dopants in this work. All affected the conductivity of the polymer matrix, but at different dopant concentrations. The percolation threshold behavior of used dopants in the polymer host showed pronounced dependence on the dopants" particle size and particle shape anisotropy. For instance, the higher the aspect ratio of carbon-based dopant particles (aspect ratio = length : diametar), the lower the percolation threshold. Additionally, increase in metallic dopants' diameter yielded higher percolation threshold of polymer composition.Keywords: polymer cholesteric liquid crystals; conductive dopants; carbon black; carbon nanotubes; percolation threshold УЛОГА НА СПРОВОДЛИВИ ДОПАНТИ ВО ПОЛИМЕРНИ ХОЛИСТЕРИЧНИ ТЕЧНИ КРИСТАЛИНајразлични спроводливи допанти се користени за модификација на својствата на полимерни холистерични течни кристали. Во овој труд како спроводливи допанти се користени различни видови јаглерод и јаглеродни наноцевки, како и метални честички. Сите тие имаат влијание врз полимерната матрица, но при различни концентрации на допантот. Прагот на перколација на користените допанти во полимерната матрица покажа зависност од големината на честиците на допантот и од анизотропијата на обликот на честиците. На пример, поголем сооднос на должината : диаметарот на допантот го намалува прагот на перколација. Понатаму, зголе-мувањето на дијаметарот на металните честички води кон повисок праг на перколација во полимерната композиција.Клучни зборови: полимерни холистерични течни кристали; спроводливи допанти; јаглерод; јаглеродни наноцевки; праг на перколација

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“…15 Ac electrical properties of metallophthalocyanines (M-Pc) such as Ni-Pc, 16,17 Co-Pc, [18][19][20] , Zn-Pc, 21,22 and Cu-Pc 23,24 were reported earlier because these compounds have attracted much more interest in the last decades. Concerning the electrical behaviors, the outcome of these investigations can be summarized as follows: first, the ac conductivity shows xs dependence with s 1 indicating a hopping conduction mechanism at low temperatures and higher frequencies.…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of new fully conjugated 2H‐ and metal‐pyrazinoporphyrazine network polymers

Abdel-Razik

El-Sayed

Hassen

2011

J of Applied Polymer Sci

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2,7-Di-tert-butylpyrene was oxidized to 2,7-di-tert-butylpyrene-4,5,9,10-tetraone. The latter through condensation reaction with vicinal diamine such as diaminomaleodinitrile afforded heterocyclic monomer, 2,7-di-tert-butyl pyrene [4,5][9,10]bis(2,3-pyrazine-5,6-dinitrile), which was cyclotetramerized to the corresponding 2H-and metal-pyrazinoporphyrazine-based network polymers (2H-PyzPz and M-PyzPz, M ¼ Co, Ni, Zn, or Cu). Elemental analytical results, Infrared, and NMR spectral data of the new prepared molecules are consistent with their assigned formulations. Molecular masses and metal contents of the synthesized polymers proved to be of high molecular masses, which confirm the efficiency of tetramerization polymerization and complexation reactions. Dielectric permittivity, e 0 , loss tangent, tan d, and ac conductivity, rac(x), of 2H-PyzPz and M-PyzPz films were studied as a function of temperature and frequency. It was found that dielectric permittivity, e 0 , decreases with the increase of frequency and increases with the increase in temperature. Ac conductivity, rac(x), is found to vary as Bxs and the frequency exponent, s, is less than unity around room temperature indicating a dominant hopping process. On the other hand, rac(T) of all samples is thermally activated with low activation energies.

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AC conductivity and dielectric measurements of metal-free phthalocyanine thin films dispersed in polycarbonate

Cited by 70 publications

References 30 publications

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films

The role of conductive dopants in polymer cholesteric liquid crystals

Dielectric properties of new fully conjugated 2H‐ and metal‐pyrazinoporphyrazine network polymers

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AC conductivity and dielectric measurements of metal-free phthalocyanine thin films dispersed in polycarbonate

Cited by 70 publications

References 30 publications

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se70Te15Bi15Films

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se70Te15Bi15Films

The role of conductive dopants in polymer cholesteric liquid crystals

Dielectric properties of new fully conjugated 2H‐ and metal‐pyrazinoporphyrazine network polymers

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Product

Resources

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Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se₇₀Te₁₅Bi₁₅Films