The Effects of Conjugation Length and Substituents on the Conductivity of Oxidatively Doped p,p’-Disubstituted Diphenylpolyenes

1989 ◽  
Vol 173 ◽  
Author(s):  
Linda S. Sapochak ◽  
David W. Polis ◽  
Art N. Bain ◽  
Paul Bryson ◽  
Larry R. Dalton ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Optical Spectroscopy ◽  
Organic Materials ◽  
Optical Nonlinearity ◽  
Conjugation Length ◽  
Oxidative Doping ◽  
Absorption Frequencies ◽  
Insight Into

ABSTRACTIt has been demonstrated that the oxidative doping of a.oo-diphenylpolyenes generates polaronic and/or bipolaronic intermediates which can be directly observed by optical spectroscopy. Furthermore, the absorption frequencies have been shown to correlate with conjugation length and the nature of the substituents. Species are stabilized by donor substituents and destabilized by acceptor substituents. We now report conductivity and ESR studies on iodine doped α,ω-diphenylpolyenes, containing donor p,p’-disubstituents. The implications of these studies can provide insight into electrical conductivity and optical nonlinearity of doped organic materials.

Bipolaron Formation and Nonlinear Optical Properties in Bis-Thienyl Polyenes

1993 ◽  
Vol 328 ◽  
Author(s):  
C. W. Spangler ◽  
M. Q. He ◽  
J. Laquindanum ◽  
L. Dalton ◽  
N. Tang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Optical Nonlinearity ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Conjugation Length ◽  
Neutral Species ◽  
Oxidative Doping ◽  
State Generation ◽  
End Caps

ABSTRACTBipolaron-like dications have been produced in both diphenyl and bis-thienyl polyenes by oxidative doping in solution. However, until now spectroscopie studies of the charge state generation beyond the hexaene have been precluded due to lack of solubility and processibility. We have now been able to extend these studies to the decaene by incorporating solubilizing substituents on the thienyl end caps. For the neutral species, degenerate four wave Mixing (DFWM) studies indicate that χ(3) is still increasing as a function of conjugation length. Introduction of mesomerically interactive RS groups on the thiophene rings further increases both solubility and optical nonlinearity.

scholarly journals Optical spectroscopy of organic materials based on C60

2014 ◽  
Vol 541 ◽  
pp. 012021 ◽  
Author(s):  
M Elistratova ◽  
N Romanov ◽  
I Zakharova ◽  
O Kvyatkovskii
Keyword(s):  
Optical Spectroscopy ◽  
Organic Materials

Vanadium-substituted Sm2Ti2O7 pyrochlore. Insight into the structure and electrical conductivity under oxidizing and highly reducing atmosphere

2019 ◽  
Vol 339 ◽  
pp. 114995 ◽  
Author(s):  
Nicoleta Cioatera ◽  
Elena-Adriana Voinea ◽  
Petre Osiceanu ◽  
Florica Papa ◽  
Alina Duță ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Reducing Atmosphere ◽  
Insight Into

Thermal-Electric Finite Element Analysis of Electrosurgical Cautery Process

2007 ◽  
Author(s):  
Robert E. Dodde ◽  
Scott F. Miller ◽  
Albert J. Shih ◽  
James D. Geiger
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Finite Element ◽  
Biological Tissue ◽  
Tissue Temperature ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Temperature Dependent Thermal Conductivity ◽  
Insight Into ◽  
Good Agreement

Cautery is a process to coagulate tissues and seal blood vessels using the heat. In this study, finite element modeling (FEM) was performed to analyze temperature distribution in biological tissue subject to cautery electrosurgical technique. FEM can provide detailed insight into the heat transfer in biological tissue to reduce the collateral thermal damage and improve the safety of cautery surgical procedure. A coupled thermal-electric FEM module was applied with temperature-dependent electrical and thermal properties for the tissue. Tissue temperature was measured at different locations during the electrosurgical experiments and compared to FEM results with good agreement. The temperature-dependent electrical conductivity has demonstrated to be critical. In comparison, the temperature-dependent thermal conductivity does not impact heat transfer as much as the electrical conductivity. FEM results show that the thermal effects can be varied with the electrode geometry that focuses the current density at the midline of the instrument profile.

scholarly journals Synthesis of AG Nanocrystal/Few-Layer Graphite Nanoplatelet Composites

2018 ◽  
Vol 27 (2) ◽  
pp. 096369351802700
Author(s):  
Shasha li ◽  
Nailiang Liu ◽  
Changqing Fang
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Electroless Plating ◽  
Organic Materials ◽  
Treatment Results ◽  
Plating Method ◽  
Distinct Boundary ◽  
Electroless Plating Method

The present study focuses on improving the combination of graphite nanoplatelet (GNP) with other organic materials without reducing its properties. An Ag nanocrystal was synthesized by electroless plating method under sonication at 40 °C, which was coated densely onto few-layer GNP and hexagon-slice GNP that was found during GNP treatment. Results illustrated that the Ag nanocrystal had uniform grain size and distinct boundary covered onto GNP. The thermal conductivity of the Ag nanocrystal /few-layer GNP (Ag/GNP) composite was superior to that of the GNP material. In addition, the Ag/GNP composite exhibited excellent electrical conductivity.

Why Gold Flash Can Be Detrimental to Long-Term Reliability

2004 ◽  
Vol 126 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Jingsong Xie ◽  
Ming Sun ◽  
Michael Pecht ◽  
David F. Barbe
Keyword(s):  
Electrical Conductivity ◽  
Stress Relaxation ◽  
Base Metal ◽  
Copper Alloys ◽  
Electrical Contacts ◽  
High Electrical Conductivity ◽  
Electrical Failure ◽  
Base Materials ◽  
Insight Into

Most connectors are made from copper or copper alloys, with beryllium copper and phosphor bronze being the most common base materials due to their high electrical conductivity, low stress relaxation, and competitive cost. The most significant drawback is copper’s low resistance to corrosion, which can lead to electrical failure of connectors. For this reason, a layer of gold is often plated on the surfaces of connectors to seal off the base metal from being directly exposed to the environment. As an economical practice, gold flashing has been used to protect electrical contacts from corrosion. However, there is increasing evidence indicating that gold flashing can be detrimental in applications calling for long-term reliability. This paper provides insight into reliability issues of gold flash.

LIGHT-INDUCED MODIFICATION OF KINETIC MOLECULAR PROPERTIES: ENHANCEMENT OF OPTICAL KERR EFFECT IN ABSORBING LIQUIDS, PHOTOINDUCED TORQUE AND MOLECULAR MOTORS IN DYE-DOPED NEMATICS

2000 ◽  
Vol 09 (02) ◽  
pp. 157-182 ◽  
Author(s):  
M. KREUZER ◽  
L. MARRUCCI ◽  
D. PAPARO
Keyword(s):  
Liquid Crystals ◽  
Molecular Motors ◽  
Kerr Effect ◽  
Optical Nonlinearity ◽  
Molecular Structures ◽  
Molecular Properties ◽  
Main Role ◽  
Theoretical Results ◽  
Insight Into ◽  
Dye Molecule

In this paper we review some experimental and theoretical results on the enhancement of orientational optical nonlinearities observed in dye-doped liquids and liquid crystals. We argue that this enhancement is derived from a photoinduced modification of kinetic molecular properties. Moreover we highlight an analogy between the mechanism of this effect in nematic liquid crystals and the working principles of "molecular motors". This analogy helps us to refine the understanding of this effect and to identify the molecular parameters which play the main role. Finally we review some recent experimental results about the dependence of the optical nonlinearity enhancement on the detailed dye and host molecular structures. These results provide some insight into the light-induced phenomena taking place inside a dye molecule.

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