Influence of Iodine on Low Frequency Dielectric Properties of Anthrone

1995 ◽  
Vol 60 (11) ◽  
pp. 1809-1814
Author(s):  
Grzegorz W. Bak ◽  
Marian Kryszewski
Keyword(s):  
Charge Transfer ◽  
Dielectric Properties ◽  
Dielectric Response ◽  
Charge Transfer Complex ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Low Loss ◽  
Remarkable Change ◽  
Ct Complex

Low frequency dielectric properties of polycrystalline anthrone and anthrone/iodine charge-transfer complex are presented. Polycrystalline anthrone proves to be a typical low-loss material. Iodization of anthrone pellets leads to a remarkable change in dielectric properties. Dielectric response of anthrone/iodine CT complex shows comparatively strong low frequency dispersion. The change in dielectric properties proves to be reversible to great extend as removing of iodine by heating at 373 K for a few hours almost completely restores the dielectric values of a virgin anthrone sample.

scholarly journals The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3230
Author(s):  
Theeranuch Nachaithong ◽  
Narong Chanlek ◽  
Pairot Moontragoon ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Barrier Layer ◽  
Dielectric Response ◽  
High Resistivity ◽  
Low Loss ◽  
Rutile Tio2 ◽  
Complex Defect ◽  
Very High ◽  
Co Doped

(Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε′ » 36,105 and a low loss tangent of tanδ » 0.04 were achieved. The sample–electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped 2Nb2Ti complex defect. These two types of complex defects are far away from each other. Therefore, the electron-pinned defect dipoles cannot be considered the primary origins of the dielectric response in the CoNTO ceramics. Impedance spectroscopy shows that the CoNTO ceramics are electrically heterogeneous, comprised of insulating and semiconducting regions. Thus, the dielectric properties of the CoNTO ceramics are attributed to the interfacial polarization at the internal insulating layers with very high resistivity, giving rise to a low loss tangent.

Spectrophotometric and photocatalytic studies of H-bonded charge transfer complex of oxalic acid with imidazole: single crystal XRD, experimental and DFT/TD-DFT studies

2019 ◽  
Vol 43 (23) ◽  
pp. 9039-9051 ◽  
Author(s):  
Ishaat M. Khan ◽  
Kehkashan Alam ◽  
Mohammad Jane Alam ◽  
Musheer Ahmad
Keyword(s):  
Hydrogen Bonding ◽  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Oxalic Acid ◽  
Single Crystal ◽  
Charge Transfer Complex ◽  
Single Crystal Xrd ◽  
Dft Studies ◽  
Td Dft ◽  
Ct Complex

The photocatalytic activity of a new CT complex was tested. Spectrophotometric studies were performed to understand its formation through N+–H⋯O− hydrogen bonding, and the structure was confirmed by single crystal XRD.

DIELECTRIC PROPERTIES OF DRY, GEOLOGIC MATERIALS

Geophysics ◽  
1970 ◽  
Vol 35 (4) ◽  
pp. 624-645 ◽  
Author(s):  
M. Saint‐Amant ◽  
David W. Strangway
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Relaxation Times ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Relaxation Peak ◽  
Debye Relaxation ◽  
Thermally Activated ◽  
Geologic Materials ◽  
Frequency Independent

A detailed investigation of the dielectric properties of powdered and solid dry rocks in the frequency range of 50 hz to 2 mhz has revealed the following general characteristics: 1) All dry rocks, powdered and solid, show an increase in both the dielectric constant and the loss tangent as frequency decreases and as temperature increases. This dispersion is believed to be due to polarization associated with charge buildup at grain boundaries or at grain imperfections. 2) Dry powdered rocks often show a thermally‐activated relaxation peak with a typical Debye‐relaxation character. This is due to the presence of pyroxene and biotite and may be associated with other minerals. The relaxation peak is not seen in solid rocks, where it is hidden by the low‐frequency dispersion. 3) At high frequencies, the loss tangent approaches a constant value which is frequency independent. This behavior is observed in many dielectrics and may be the result of a distribution of relaxation times.

The bis(ethylenedithio)tetrathiafulvalene-based ionic charge-transfer complex with 2,3-dichloro-5,6-dicyano-p-benzoquinone

2013 ◽  
Vol 69 (4) ◽  
pp. 400-402
Author(s):  
Yuki Nakagawa ◽  
Yukihiro Takahashi ◽  
Jun Harada ◽  
Tamotsu Inabe
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Ionic Charge ◽  
One Dimensional ◽  
Face To Face ◽  
Ladder System ◽  
Donor And Acceptor ◽  
Ct Complex ◽  
Centrosymmetric Dimers ◽  
Ct Complexes

In the ionic charge-transfer (CT) complex composed of bis(ethylenedithio)tetrathiafulvalene (ET) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), C10H8S8·C8Cl2N2O2, the donor and acceptor molecules both form centrosymmetric dimers associated by strong face-to-face π–π interactions. The disordered DDQ molecules form a one-dimensional π-stacked column, while the ET molecules form a two-leg ladder through additional short S...S contacts between adjacent π–π-bonded dimers. The crystal structure of ET–DDQ revealed in this study will provide a valuable example of the two-leg spin ladder system, which has rarely been reported for ET-based CT complexes.

scholarly journals Stable dielectric response of low-loss aromatic polythiourea thin films on Pt/SiO2 substrate

2016 ◽  
Vol 06 (01) ◽  
pp. 1650003 ◽  
Author(s):  
A. Eršte ◽  
L. Fulanović ◽  
L. Čoga ◽  
M. Lin ◽  
Y. Thakur ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Response ◽  
High Density Polyethylene ◽  
Dielectric Losses ◽  
Low Loss ◽  
Promising Candidate ◽  
Sio2 Substrate ◽  
Polar Polymer

We have investigated dielectric properties of aromatic polythiourea (ArPTU, a polar polymer containing high dipolar moments with very low defect levels) thin films that were developed on Pt/SiO2 substrate. The detected response is compared to the response of commercially available polymers, such as high density polyethylene (HDPE) and polypropylene (PP), which are at present used in foil capacitors. Stable values of the dielectric constant [Formula: see text] (being twice higher than in HDPE and PP) over broad temperature and frequency ranges and dielectric losses as low as in commercial systems suggest ArPTU as a promising candidate for future use in a variety of applications.

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