Effects of Interfacial Modifications on Electrical Properties of Laminar Composite Dielectrics

Tewari, Pratyush; Rajagopalan, Ramakrishnan; Furman, Eugene; Lanagan, Michael T.

doi:10.1021/la1033367

Cited by 6 publications

(4 citation statements)

References 31 publications

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“…This value, higher than that of pristine LFPC (0.18 eV), 26 underlines that physisorbed ACN and DMF molecules detected by XPS likely add barriers to the electron hopping by the trapping effect, which would arise from their high dipole moment. Recently, a similar phenomenon was reported on laminar silica-polymer composite dielectrics 52 and Li 1.1 V 3 O 8 particles. 53 Surprisingly enough, in the case of LFPC-EB-2L (Fig.…”

Section: Electronic Transport Properties Of Solvent and Functionalize...supporting

confidence: 77%

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄

Madec

Seïd

Badot

et al. 2014

Phys. Chem. Chem. Phys.

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The morphological and the electrical properties of carbon coated LiFePO4 (LFPC) active material functionalized by 4-ethynylbenzene tetrafluoroboratediazonium salt were investigated. For this purpose, FTIR, Raman, XPS, High Resolution Transmission Electron Microscopy (HRTEM) and Broadband Dielectric Spectroscopy (BDS) were considered. Electronic conductivities of LFPC samples at room temperature were found to decrease in a large frequency range upon simple immersion in polar solvents and to decrease further upon functionalization. Due to their high dipole moment, strongly physisorbed molecules detected by XPS likely add barriers to electron hopping. Significant alteration of the carbon coating conductivity was only observed, however, upon functionalization. This effect is most presumably associated with an increase in the sp(3) content determined by Raman spectroscopy, which is a strong indication of the formation of a covalent bond between the organic layer and the carbon coating. In this case, the electron flux appears to be redirected and relayed by short-range (intra chain) and long-range (inter chain) electron transport through molecular oligomers anchored at the LFPC surface. The latter are controlled by tunnelling and slightly activated hopping, which enable higher conductivity at low temperature (T < 250 K). Alteration of the electron transport within the carbon coating also allows detection of a relaxation phenomenon that corresponds to small polaron hopping in bulk LiFePO4. XPS and HRTEM images allow a clear correlation of these findings with the island type oligomeric structure of grafted molecules.

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Section: Electronic Transport Properties Of Solvent and Functionalize...supporting

confidence: 77%

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄

Madec

Seïd

Badot

et al. 2014

Phys. Chem. Chem. Phys.

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“…Polar surfactants were observed to influence the dipolar relaxations, generating higher activation energy dipolar states at interfaces. 54 Since the frequency prefactor of the relaxations P 3 0 , P 4 and P 5 (i.e. n 0 E 4 Â 10 9 Hz) is lower than the phonon frequencies (i.e.…”

Section: Electronic Transport Properties and Dielectric Relaxationsmentioning

confidence: 99%

Influence of adsorbed polar molecules on the electronic transport in a composite material Li1.1V3O8–PMMA for lithium batteries

Badot

Ligneel

Dubrunfaut

et al. 2012

Phys. Chem. Chem. Phys.

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The broadband dielectric spectroscopy (BDS) technique (40 to 10(10) Hz) is used here to measure the electronic transport across all observed size scales of a Li(1.1)V(3)O(8)-polymer-gel composite material for lithium batteries. Different electrical relaxations are evidenced, resulting from the polarizations at the different scales of the architecture: (i) atomic lattice (small-polaron hopping), (ii) particles, (iii) clusters of particles, and finally (iv) sample-current collector interface. A very good agreement with dc-conductivity measurements on a single macro-crystal [M. Onoda and I. Amemiya, J. Phys.: Condens. Matter, 2003, 15, 3079.] shows that the BDS technique does allow probing the bulk (intrinsic) electrical properties of a material in the form of a network of particles separated by boundaries in a composite. Moreover, this study highlights a lowering of the surface electronic conductivity of Li(1.1)V(3)O(8) particles upon adsorption of polar ethylene carbonate (EC) and propylene carbonate (PC) that trap surface polarons. This result is meaningful as EC and PC are typical constituents of a liquid electrolyte of lithium batteries. It is thus suggested that interactions between active material particles and the liquid electrolyte play a role in the electronic transport within composite electrodes used in a lithium battery.

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“…PPXC is also an appropriate hydroxyl-free gate dielectric and prevents trapping of electrons at the semiconductor–dielectric interface in contrast to polymers containing hydroxyl groups such as poly(vinyl phenol) and polyimides (due to residual COOH groups) [18–20]. The stability of the devices, which is impacted by this charge trapping at the interfaces, is improved when parylene C is integrated in the device [21–22]. Parylene C is highly corrosion resistant on metallic surfaces and possesses outstanding electrical insulation with high tensile strength, moderate dielectric losses [16,23] and low permeability to gases [24–25].…”

Section: Introductionmentioning

confidence: 99%

Nanocomposite–parylene C thin films with high dielectric constant and low losses for future organic electronic devices

Mokni¹,

Maggioni²,

Carturan³

et al. 2019

Beilstein J. Nanotechnol.

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Nanocomposite–parylene C (NCPC) thin films were deposited with a new technique based on the combination of chemical vapor deposition (CVD) for parylene C deposition and RF-magnetron sputtering for silver deposition. This method yields good dispersion of Ag-containing nanoparticles inside the parylene C polymer matrix. Film composition and structure were studied by using several techniques. It was found that the plasma generated by the RF-magnetron reactor modifies the film density as well as the degree of crystallinity and the size of parylene C crystallites. Moreover, silver is incorporated in the parylene matrix as an oxide phase. The average size of the Ag oxide nanoparticles is lower than 20 nm and influences the roughness of the NCPC films. Samples with various contents and sizes of silver-oxide nanoparticles were investigated by broadband dielectric spectroscopy (BDS) in view of their final application. It was found that both the content and the size of the nanoparticles influence the value of the dielectric constant and the frequency-dependence of the permittivity. In particular, β-relaxation is affected by the addition of nanoparticles as well as the dissipation factor, which is even improved. A dielectric constant of 5 ± 1 with a dissipation factor of less than 0.045 in the range from 0.1 Hz to 1 MHz is obtained for a 2.7 µm thick NCPC with 3.8% Ag content. This study provides guidance for future NCPC materials for insulating gates in organic field-effect transistors (OFETs) and advanced electronic applications.

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Effects of Interfacial Modifications on Electrical Properties of Laminar Composite Dielectrics

Cited by 6 publications

References 31 publications

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄

Influence of adsorbed polar molecules on the electronic transport in a composite material Li1.1V3O8–PMMA for lithium batteries

Nanocomposite–parylene C thin films with high dielectric constant and low losses for future organic electronic devices

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Effects of Interfacial Modifications on Electrical Properties of Laminar Composite Dielectrics

Cited by 6 publications

References 31 publications

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO4

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO4

Influence of adsorbed polar molecules on the electronic transport in a composite material Li1.1V3O8–PMMA for lithium batteries

Nanocomposite–parylene C thin films with high dielectric constant and low losses for future organic electronic devices

Contact Info

Product

Resources

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Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄

Redirected charge transport arising from diazonium grafting of carbon coated LiFePO₄