scholarly journals Visualization of an Accelerated Electrochemical Reaction under an Enhanced Electric Field

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Chen Cui ◽  
Rong Jin ◽  
Dechen Jiang ◽  
Jianrong Zhang ◽  
Junjie Zhu
Keyword(s):  
Electric Field ◽  
Charge Transport ◽  
Electric Fields ◽  
Electrochemical Reaction ◽  
Ruthenium Complex ◽  
Electron Transfer Mechanism ◽  
Heterogeneous Interfaces ◽  
Electrochemical Mechanism ◽  
High Electric Fields ◽  
First Time

Locally enhanced electric fields produced by high-curvature structures have been reported to boost the charge transport process and improve the relevant catalytic activity. However, no visual evidence has been achieved to support this new electrochemical mechanism. Here, accelerated electrochemiluminescence (ECL) reactions emitting light are visualized for the first time at the heterogeneous interfaces between microbowls and the supporting electrode surface. The simulation result shows that the electric intensity at the interface with a high curvature is 40-fold higher than that at the planar surface. Consequently, local high electric fields concentrate reactive species to the heterogeneous interfaces and efficiently promote the charge transport reactions, which directly leads to the enhancement of ECL emission surrounding the microbowls. Additionally, the potential to induce visual ECL from a ruthenium complex drops to 0.9 V, which further illustrates the promotion of an electrochemical reaction with the aid of an enhanced electric field. This important visualization of electric field boosted electrochemical reactions helps to establish the proposed electron transfer mechanism and provide an alternative strategy to improve electrocatalytic efficiency.

Research on Charge Transport in One-Dimensional Organic Semiconductors Material

2012 ◽  
Vol 531 ◽  
pp. 231-234 ◽  
Author(s):  
Wen Liu
Keyword(s):  
Electric Field ◽  
Charge Transport ◽  
Organic Semiconductors ◽  
Electric Fields ◽  
One Dimensional ◽  
Organic Semiconductor Materials ◽  
Insulator Metal Transition ◽  
The Family ◽  
High Electric Fields ◽  
Ssh Model

1D conjugated polymers belong to the family of organic semiconductor materials, in which the charge carriers are polarons or bipolarons. Charge transport in 1D organic semiconductors in the presence of high electric fields is studied within the SSH model. It is found that under a sufficiently high electric field, the polaron is dissociated into free-like electron. The electron performs Bloch oscillation (BO) in the organic semiconductors. By enhancing the electric field, BO will be destroyed and electrons can transit from the valence band to the conduction band, which is Zener tunneling in organic semiconductors. The results also indicate a field-induced insulator-metal transition.

Photoelectronic properties of YBa2Cu3O6

1993 ◽  
Vol 71 (11-12) ◽  
pp. 512-517
Author(s):  
Bruno Ullrich ◽  
Ibrahim Kulaç ◽  
Harald Pint
Keyword(s):  
Band Structure ◽  
Electric Field ◽  
Electric Fields ◽  
Fair Agreement ◽  
Luminescence Properties ◽  
Tunneling Phenomena ◽  
High Electric Fields ◽  
First Time ◽  
Franz Keldysh Effect ◽  
Complex Manner

The photocurrent and luminescence properties of thin (1 μm) YBa2Cu3O6 films on sapphire at 77 and 300 K are reported. We demonstrate that the luminescence mechanism of YBa2Cu3O6 depends considerably on the wavelength of the excitation used. Completely different luminescence responses are observed with the 351 and 458 nm lines. A fair agreement, like that in semiconductors with band-to-band transitions, is found between photocurrent and luminescence excited by the 458 nm line. The influence of high electric fields (≤ 5 780 V cm−1) on the photocurrent and luminescence of YBa2Cu3O6 is investigated for the first time. Similar effects on photon-induced tunneling phenomena (Franz–Keldysh effect) are observed. However, we show that the observed effects cannot be explained by photon-induced tunneling phenomena only since the influence of an electric field on the band structure of YBa2Cu3O6 is not only restricted to a bending of bands but modifies the band structure in a more complex manner.

Effect of a High Electric Field on the Thermal and Phase Change Characteristics of an Impacting Drop

2019 ◽  
Author(s):  
Abhishek Basavanna ◽  
Prajakta Khapekar ◽  
Navdeep Singh Dhillon
Keyword(s):  
Heat Transfer ◽  
Electric Field ◽  
Phase Change ◽  
Electric Fields ◽  
High Speed ◽  
Impact Behavior ◽  
Liquid Drops ◽  
Active Interest ◽  
Post Impact ◽  
High Electric Fields

Abstract The effect of applied electric fields on the behavior of liquids and their interaction with solid surfaces has been a topic of active interest for many decades. This has important implications in phase change heat transfer processes such as evaporation, boiling, and condensation. Although the effect of low to moderate voltages has been studied, there is a need to explore the interaction of high electric fields with liquid drops and bubbles, and their effect on heat transfer and phase change. In this study, we employ a high speed optical camera to study the dynamics of a liquid drop impacting a hot substrate under the application of high electric fields. Experimental results indicate a significant change in the pre- and post-impact behavior of the drop. Prior to impact, the applied electric field elongates the drop in the direction of the electric field. Post-impact, the recoil phase of the drop is significantly affected by charging effects. Further, a significant amount of micro-droplet ejection is observed with an increase in the applied voltage.

OBIC Analysis of Different Edge Terminations of Planar 1.6 kV 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 1007-1010 ◽  
Author(s):  
Christophe Raynaud ◽  
Daniel Loup ◽  
Phillippe Godignon ◽  
Raul Perez Rodriguez ◽  
Dominique Tournier ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Semiconductor Devices ◽  
Optical Beam ◽  
Induced Current ◽  
Bipolar Diodes ◽  
High Electric Fields ◽  
Optical Beam Induced Current

High voltage SiC semiconductor devices have been successfully fabricated and some of them are commercially available [1]. To achieve experimental breakdown voltage values as close as possible to the theoretical value, i.e. value of the theoretical semi-infinite diode, it is necessary to protect the periphery of the devices against premature breakdown due to locally high electric fields. Mesa structures and junction termination extension (JTE) as well as guard rings, and combinations of these techniques, have been successfully employed. Each of them has particular drawbacks. Especially, JTE are difficult to optimize in terms of impurity dose to implant, as well as in terms of geometric dimensions. This paper is a study of the spreading of the electric field at the edge of bipolar diodes protected by JTE and field rings, by optical beam induced current.

Calculations of Some Transport Coefficients in Simple Semiconductors at Low Temperatures and High Electric Fields

1971 ◽  
Vol 49 (7) ◽  
pp. 876-880 ◽  
Author(s):  
Jyoti Kamal ◽  
Satish Sharma
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Low Temperatures ◽  
Transport Coefficients ◽  
Drift Mobility ◽  
Temperature Dependent ◽  
Hall Constant ◽  
The Difference ◽  
High Electric Fields ◽  
Model Semiconductor

In this paper the authors have calculated Hall mobility, drift mobility, and Hall constant for a non-degenerate simple model semiconductor at low temperatures for an arbitrary electric field strength. Following Paranjape the modified distribution of phonons has been taken into account. The difference between the calculations of transport coefficients made by taking into account the modified phonon distribution and by not taking it into account is quite appreciable at high electric field. Calculations also show that for Ne = 1016/cm3 the mobility of electrons remains temperature dependent.

scholarly journals Corona at Large Coated Electrodes

2018 ◽  
Author(s):  
Mats Larsson ◽  
Olof Hjortstam ◽  
Håkan Faleke ◽  
Liliana Arevalo ◽  
Dong Wu ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Negative Polarity ◽  
Electrode Geometry ◽  
Positive Polarity ◽  
Electrical Fields ◽  
Insulating Material ◽  
Air Gaps ◽  
High Electric Fields ◽  
Coated Electrodes

<p>In geometries relevant form HVDC applications where large electrodes and large air gaps are utilized, the observed corona can be quite different from geometries studied in the literature where needles or wires are used as high voltage electrodes. Corona discharges at large electrodes often initiates when the electric field on the electrode surface appears lower than the critical electric field strength, 2.4 kV/mm. Surface contamination of the electrode has been pointed out as the reason for such discharge events. Our experimental results indicate that one possible way to prevent such corona is to coat the electrode with an insulating material, such as epoxy or oxide layers. It seems that the layer separates any corona inducing particle from the electrode, which in turn hinders the corona to form. However, as the layer breaks down and gets punctured, the corona preventing propertied disappears and corona forms easily. We conclude that as long as the layer doesn’t get punctured, coating electrodes with insulating material is preventing corona to initiate at electrical fields below the critical electric field, as given by the electrode geometry. In contrast to positive polarity, for negative polarity the epoxy coating could withstand high electric fields without breaking down.</p>

Driftgeschwindigkeit und Beweglichkeit von Elektronen in Silicium bei 4,2 °K in Abhängigkeit vom elektrischen Feld / Driftvelocity and Mobility of Electrons in Silicon at 4.2 °K in Dependence of Electric Field

1972 ◽  
Vol 27 (1) ◽  
pp. 26-30
Author(s):  
P. Deimel
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Silicon Surface ◽  
Surface Barrier ◽  
Surface Barrier Detector ◽  
Direct Information ◽  
Fully Depleted ◽  
Barrier Detector ◽  
High Electric Fields ◽  
Silicon Surface Barrier Detector

Abstract The pulse rise times of an n-type silicon surface barrier detector were measured at 4.2 °K. At this temperature the detector was fully depleted even at very low bias and the measured pulse rise times gave direct information about the driftvelocity and the mobility. Instead of E-0.5, an E-0.8 dependence of the mobility at moderate electric fields was found. At high electric fields agreement exists with theory.

Numerical Simulation of Microscale Ion-Driven Air Flow

2003 ◽  
Author(s):  
Daniel J. Schlitz ◽  
Suresh V. Garimella ◽  
Timothy S. Fisher
Keyword(s):  
Electric Field ◽  
Charge Transport ◽  
Electric Fields ◽  
Air Flow ◽  
Maximum Velocity ◽  
Electronics Cooling ◽  
Pressure Head ◽  
Switching Frequency ◽  
Field Equations ◽  
Scale Motion

Ion-driven air flow is a novel method of pumping air at microscale dimensions using the concept of ion drag. The method employs a series of micro-fabricated electrodes to generate strong electric fields that pump unipolar ions through air. Ions collide repeatedly with neutral molecules, thus generating bulk motion of the gas. Meso-scale motion is obtained by changing the voltage of electrodes rapidly over time to create a nearly continuous force on the ions. One application of this technology involves generation of air flow through microchannels or other micro-featured surfaces to create compact, high flux heat sinks for electronics cooling. A numerical model of the fluid-ion-electric field interaction has been developed. The momentum and continuity equations are supplemented with equations for electric charge transport and for electric potential. The momentum equations are coupled through a body-force term to the charge transport and electric field equations, both of which are coupled to the momentum equations and to each other through source and convection terms. The model describes the one-dimensional, time-dependent flow of air and ions between evenly spaced microscale planar electrodes, of which the voltages are switched at frequencies on the order of 1 MHz. The flow is investigated to determine the effect of switching frequency on maximum velocity and pressure head.

Magnitude of Intrinsic Electrocaloric Effect in Pb(Zr1-xTix)O3 at High Electric Fields

2013 ◽  
Vol 700 ◽  
pp. 7-10
Author(s):  
Wen Jiang Feng ◽  
Zhi Guo Zhang ◽  
Chuang Wu ◽  
Hao Chen
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Transition ◽  
Strong Electric Field ◽  
Zero Field ◽  
Electrocaloric Effect ◽  
Structure Transition ◽  
First Order ◽  
High Electric Fields ◽  
Curie Temperatures

The structure transition and electrocaloric effect in PbZr1-xTixO3withx=0.5 and 0.6 were MV/m can make the structural transition be a continuous one. In addition, whenx=0.5 and 0.6 at the zero field, the first order structural transition occurs atT0=665 and 691 K, respectively. The first order structural transition comes to the second one upon the strong electric field, which leads to lower the change of specific hea. The structural transition temperature is shifted at high temperature with increasing electric field. The maximum electrocaloric effect is present at about 200 K above their corresponding Curie temperatures.

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