Ultrafast polaron-pair dynamics in a poly(3-hexylthiophene-2,5-diyl) device influenced by a static electric field: insights into electric-field-related charge loss

2019 ◽  
Vol 21 (38) ◽  
pp. 21236-21248 ◽  
Author(s):  
Debkumar Rana ◽  
Patrice Donfack ◽  
Vladislav Jovanov ◽  
Veit Wagner ◽  
Arnulf Materny

Photogenerated polaron-pair ultrafast dynamics in poly(3-hexylthiophene)-based devices are found to be influenced by external electric fields via delayed field-induced singlet exciton dissociation, yielding a bimolecular decay contribution.

2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Peter Kraus ◽  
Julian Gale

Molecular dynamics simulations of the liquid-liquid interface between water and 1,2-Dichloroethane in the presence of weak external electric fields.<div>The effect of the use of 3D periodic Ewald summation and the effect of the simulation setup are discussed.</div><div>A new simple geometric method for designing the simulation cell is proposed. This method was thoroughly tested shown that it mitigates any artefacts to the use of 3D Ewald summation with external electric field.</div>


2020 ◽  
Author(s):  
L. Martinez ◽  
A. Dhruv ◽  
L. Lin ◽  
E. Balaras ◽  
M. Keidar

AbstractThis paper presents a numerical model to investigate the deformation of biological cells by applying external electric fields operating at or near cell resonant frequencies. Cells are represented as pseudo solids with high viscosity suspended in liquid media. The electric field source is an atmospheric plasma jet developed inhouse, for which the emitted energy distribution has been measured.Viscoelastic response is resolved in the entire cell structure by solving a deformation matrix assuming an isotropic material with a prescribed modulus of elasticity. To investigate cell deformation at resonant frequencies, one mode of natural cell oscillation is considered in which the cell membrane is made to radially move about its eigenfrequency. An electromagnetic wave source interacts with the cell and induces oscillation and viscoelastic response. The source carries energy in the form of a distribution function which couples a range of oscillating frequencies with electric field amplitude.Results show that cell response may be increased by the external electric field operating at or near resonance. In the elastic regime, response increases until a steady threshold value, and the structure moves as a damped oscillator. Generally, this response is a function of both frequency and magnitude of the source, with a maximum effect found at resonance. To understand the full effect of the source energy spectrum, the system is solved by considering five frequency-amplitude couplings. Results show that the total solution is a nonlinear combination of the individual solutions. Additionally, sources with different signal phases are simulated to determine the effect of initial conditions on the evolution of the system, and the result suggests that there may be multiple solutions within the same order of magnitude for elastic response and velocity. Cell rupture from electric stress may occur during application given a high energy source.SignificanceCold atmospheric plasma jets (CAPJs) have been widely researched for their potential applications in cancer therapy. Existing research has focused mainly on the ability of CAPJs to deliver a mixture of reactive species which can be absorbed by cancer cells and induce cell death. The objective of our study is to investigate the mechanical effect of CAPJ electromagnetic (EM) waves on interacting cells. By coupling the EM waves associated with plasma frequency and cell viscoelastic response, we have developed a numerical tool to investigate cell damage either by mechanical or thermal loads. This work is motivated by the promise of EM waves to function as a sensitizing agent for cancer cells in preparation for chemotherapy.


2020 ◽  
Vol 6 (21) ◽  
pp. eaaz2915 ◽  
Author(s):  
Zdenek Futera ◽  
John S. Tse ◽  
Niall J. English

In a superionic (SI) ice phase, oxygen atoms remain crystallographically ordered while protons become fully diffusive as a result of intramolecular dissociation. Ice VII’s importance as a potential candidate for a SI ice phase has been conjectured from anomalous proton diffusivity data. Theoretical studies indicate possible SI prevalence in large-planet mantles (e.g., Uranus and Neptune) and exoplanets. Here, we realize sustainable SI behavior in ice VII by means of externally applied electric fields, using state-of-the-art nonequilibrium ab initio molecular dynamics to witness at first hand the protons’ fluid dance through a dipole-ordered ice VII lattice. We point out the possibility of SI ice VII on Venus, in its strong permanent electric field.


Author(s):  
Zheyan Jin ◽  
Hui Hu

An experimental study was conducted to further our understanding about the fundamental physics of electrokinetic instability (EKI) and to explore the effectiveness to enhance fluid mixing inside a Y-shaped microchannel by manipulating convective EKI waves. The dependence of the critical voltage of applied static electric field to trig EKI to generate convective EKI waves on the conductivity ratio of the two adjacent streams was quantified at first. The effect of the strength of the applied static electric field on the evolution of the convective EKI waves and fluid mixing process were assessed in terms of scalar concentration fields, shedding frequency of the convective EKI waves and scalar mixing efficiency. The effectiveness of manipulating the convective EKI waves by introducing alternative electric perturbations to the applied static electric fields was also explored for the further enhancement of the fluid mixing process inside the Y-shaped microchannel.


2017 ◽  
Vol 19 (47) ◽  
pp. 31958-31964 ◽  
Author(s):  
Feng-Wei Gao ◽  
Hong-liang Xu ◽  
Zhong-Min Su

Different strengths of external electric fields enhance the stability, control the inter-molecular charge transfer and strengthen the nonlinear optical responses of a π-dimer.


Author(s):  
Alexey A. Eronin ◽  
Stanislav P. Malyshenko ◽  
Anton I. Zhuravlev

Characteristics of heat transfer and hydrodynamics of boiling of liquid nitrogen on the surfaces with different types of non-uniformities at the presence of external electric fields are experimentally investigated. It is shown that the formation of field traps is a major mechanism of heat transfer enhancement. And this effect result in noticeable change of two-phase hydrodynamics in vicinity of heated surface.


2020 ◽  
Author(s):  
Matthew Hennefarth ◽  
Anastassia N. Alexandrova

<div> <div> <div> <p>External electric fields have proven to be an effective tool in catalysis, on par with pressure and temperature, affecting the thermodynamics and kinetics of a reaction. However, fields in molecules are complicated heterogeneous vector objects, and there is no universal recipe for grasping the exact features of these fields that implicate reactivity. Herein, we demonstrate that topological features of the heterogeneous electric field within the reactant state, as well as of the quantum mechanical electron density – a scalar reporter on the field experienced by the system – can be identified as rigorous descriptors of the reactivity to follow. We scrutinize specifically the Diels-Alder reaction. Its 3-D nature and the lack of a singular directionality of charge movement upon barrier crossing makes the effect of the electric field not obvious. We show that the electric field topology around the dienophile double bond, and the associated changes in the topology of the electron density in this bond are predictors of the reaction barrier. They are also the metrics by which to rationalize and predict how the external field would inhibit or enhance the reaction. The findings pave the way toward designing external fields for catalysis, as well as reading the reactivity without an explicit mechanistic interrogation, for a variety of reactions. </p> </div> </div> </div>


2018 ◽  
Vol 63 (6) ◽  
pp. 531 ◽  
Author(s):  
W. Thongpan ◽  
T. Kumpika ◽  
E. Kantarak ◽  
A. Panthawan ◽  
P. Pooseekheaw ◽  
...  

We have used an external electric field to increase both the uniformity and deposition rate of TiO2 films. The experiment is carried out by sparking-off titanium wires with a high dc voltage of 1 kV (field Eint = 10 kV/cm) and a limited current of 3 mA. The external electric fields (Eext) of 3, 6, and 9 kV/cm were applied to the sparking system for 1–5 hours. The as-deposited film morphology was characterized by scanning electron microscopy. The results clearly show that the films are only deposited on the external electric field area. Furthermore, the deposition rate of the films increased from 40.7% to 77.8% in the presence of the external electric field of 9 kV/cm. The effects of an external electric field on both the deposition rate and uniformity of films are investigated and described.


2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Peter Kraus ◽  
Julian Gale

Molecular dynamics simulations of the liquid-liquid interface between water and 1,2-Dichloroethane in the presence of weak external electric fields.<div>The effect of the use of 3D periodic Ewald summation and the effect of the simulation setup are discussed.</div><div>A new simple geometric method for designing the simulation cell is proposed. This method was thoroughly tested shown that it mitigates any artefacts to the use of 3D Ewald summation with external electric field.</div>


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Xi-Guang Wang ◽  
Levan Chotorlishvili ◽  
Vitalii K. Dugaev ◽  
Arthur Ernst ◽  
Igor V. Maznichenko ◽  
...  

Abstract In a spin-driven multiferroic system, the magnetoelectric coupling has the form of effective dynamical Dzyaloshinskii–Moriya (DM) interaction. Experimentally, it is confirmed, for instance, for Cu2OSeO3, that the DM interaction has an essential role in the formation of skyrmions, which are topologically protected magnetic structures. Those skyrmions are very robust and can be manipulated through an electric field. The external electric field couples to the spin-driven ferroelectric polarization and the skyrmionic magnetic texture emerged due to the DM interaction. In this work, we demonstrate the effect of optical tweezing. For a particular configuration of the external electric fields it is possible to trap or release the skyrmions in a highly controlled manner. The functionality of the proposed tweezer is visualized by micromagnetic simulations and model analysis.


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