Thermally stimulated polarization current technique for measuring the electrical conductivity of vitreous solids

Hong, Chi-Ming; Day, Delbert E.

doi:10.1063/1.326635

Cited by 33 publications

(5 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As can be seen, similar profiles are shown in Figure b. For Cz100PF and PVK, two peaks are clearly observed for each case; the one at low temperatures (120 and 130 K, respectively) does not appear in the corresponding PE TSC spectra of the bipolar devices of Cz100PF and PVK, indicating that it is a thermally stimulated depolarization current,12d as also is evidenced by the appearance of a symmetric peak upon reversed bias. The other at the higher temperatures of 220 K (with a shoulder at 185 K) and 230 K (with a shoulder at 185 K), respectively, have PE TSC counterparts and hence can be attributed to the hole-trapped current.…”

Section: Resultssupporting

confidence: 71%

See 1 more Smart Citation

Investigating Side Chain Mediated Electroluminescence from Carbazole-Modified Polyfluorene

et al. 2007

View full text Add to dashboard Cite

In molecular design of electroluminescent (EL) conjugated polymers, introducing a charge transport moiety on a side chain is found to be a promising method for balancing electron and hole fluxes in EL devices without changing the emitting color if there is no interaction between moiety and main chain. In the case of grafting a carbazole (Cz) moiety (hole transporting) on blue emitting polyfluorene, a green emission appears with intensity comparable to the blue emission, which was attributed to a possible interaction between main chain and Cz as previously reported by us. Here, a detailed study of its EL mechanism was carried out by means of time-resolved EL with the assistance of molecular simulation and thermally stimulated current measurements; exploration of how main chain segments interact with the transport moiety was performed. We found the Cz groups in Cz100PF play multiple roles: they act as (1) hole transporter to improve hole injection, (2) hole trapping site for efficient electron-hole recombination to yield blue-emitting excitons, and (3) source of green emission from electroplex formed via electric field-mediated interaction of the Cz/Cz radical cation with an electron in the nearby PF backbone. In combination, these observations suggest that integrated consideration for both intramolecular and intermolecular interactions provides a new route of molecular design of efficient EL polymers.

show abstract

Section: Resultssupporting

confidence: 71%

“…TSC Measurements. The existence of a trap and its energy level, concentration, and polarity in organic materials have been successfully investigated by using the thermally stimulated current (TSC) technique. In the fabrication of a device for TSC measurement, a polymer film (ca.…”

Section: Methodsmentioning

confidence: 99%

Investigating Side Chain Mediated Electroluminescence from Carbazole-Modified Polyfluorene

et al. 2007

View full text Add to dashboard Cite

show abstract

“…8) and the time constant and sensitivity of the equipment. The method is usually most suitable in the range The application of TSP for measuring the electrical conductivity of, e.g., oxide glasses is recommended in [83]. Adamec [31, 321 used IRC measurements on multilayer structures, e.g., Mylar-polyethylene-Mylar in order to prove whether the conductivity in polyethylene was an intrinsic process or whether it was the result of a carrier injection from the electrodes.…”

Section: Conduction Processes In Bulk Samplesmentioning

confidence: 99%

Electric relaxation currents in high-resistivity solids

Müller¹

1981

Phys. Stat. Sol. (a)

View full text Add to dashboard Cite

“…A more convincing argument for the proposed attribution, also pointed out by Ong and Jacobs [3], is found in the similarity between the activation enthalpy for the reorientation of type II dipoles in BaF 2 : La 3+, and that for the only relaxation observed in the TSP spectrum of BaF 2 :Tb 3+ [18]. Since the ionic radii of Tb 3+ and Gd 3+ are almost the same, it is no doubt correct to attribute this relaxation to nnn associates.…”

Section: Z Simple Associatesmentioning

confidence: 68%

Low-temperature ionic conductivity and dielectric relaxation phenomena in fluorite-type solid solutions

Wapenaar

Koekkoek

1982

Solid State Ionics

View full text Add to dashboard Cite

Low-temperature ionic conductivity and dielectric relaxation phenomena in Ba 1 _xLaxF2+x crystals (1.19 X 10 -3 < x < 0.492) have been studied by ionic thermal current (ITC) and ac dielectric loss (DL) techniques. The conductivity results agree with those of an earlier ~tudy of the same crystals at higher temperatures. At low LaF 3 concentrations, i.e. 1.19 X 10 -3 ~ x ~ 2.37 X 10 -2 , the dielectric spectra show three relaxation peaks, two of which are ascribed to simple associates of interstitial F-ions (Fi) nearest-neighbour (nm) and next-nearest-neighbour (nnn) to substitutional La 3÷ ions (LaBa). They are denoted as type I and II dipoles, respectively. We attribute the third peak to angled ("L-shaped") (LaBa2~'i}' complexes. Relaxation parat~etors for the relaxations are presented. We have calculated effective dipole moments for type I . eli eli .and II dipole8 PI and/Zli , taking rote account the displacements and polarizabilities of the defects. Several combinations of host lattice cations and dQpant ions have been co~idered for the fluorites M l -xRExF2+x, i.e. M = Ca, S~Ba, and RE = La, Eu, Lu. For nearly all combinations the ratio ~[f/~ff is found to have a value of 2.4 ± 0.1. With the tt eII values thus obtained, the dipole concentrations of type I and II dipoles can be calculated. Their dependence on solute content is discussed. In the calculations, Debye-Hiickel-Lidiard interactions between defects and the charge clouds surrounding them have been taken into account. At high concentrations, i.e. 0.133 < x < 0.492, broad structureless absorption losses dominate the dielectric relaxation spectra. These losses are analysed by the fractional polarization (FP) technique, and by a special analysis of the DL data. The feasibility of these techniques is discussed. The analysis reveals that two localized relaxation processes occur in concentrated solid solutions. One is characterized by reorientation activation enthalpies (AH R) which are ghe same as the corresponding conductivity activation enthalpies (AH), and is ascr~ed to F-interstitial motion in crystal areas around defect clusters. The second process is characterized by AH R values which are much lower than AH. We propose that this process is related to F-interstitial reorientation within clusters. The results presented indicate that no typical polarizable cluster is preferred in concentrated Ba I _xLaxF2+x solid solutions.

show abstract

Thermally stimulated polarization current technique for measuring the electrical conductivity of vitreous solids

Cited by 33 publications

References 8 publications

Investigating Side Chain Mediated Electroluminescence from Carbazole-Modified Polyfluorene

Investigating Side Chain Mediated Electroluminescence from Carbazole-Modified Polyfluorene

Electric relaxation currents in high-resistivity solids

Low-temperature ionic conductivity and dielectric relaxation phenomena in fluorite-type solid solutions

Contact Info

Product

Resources

About