Computational Study of Excess Electron Mobility in High-Pressure Liquid Benzene

Sato, Masahiro; Kumada, Akiko; Hidaka, Kunihiko; Hirano, Tôru; Sato, Fumitoshi

doi:10.1021/acs.jpcc.6b01581

Cited by 26 publications

(11 citation statements)

References 83 publications

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“…The TRMC signal was smaller for electrons on F8BT, corresponding to a mobility of 0.09 cm 2 /Vs which is close in magnitude to 0.08 cm 2 /Vs, the mobility of electrons in liquid benzene at high pressure thought to occur by electron hopping between localized states. 62,63 As charge transport is most likely limited by electronic coupling fluctuations through dihedral angles, it is not possible to say for sure that the electrons are localized or free. If a rigid, planar, push pull polymer could be measured, we could distinguish the effects of localization and corrugated potential more clearly.…”

Section: ■ Discussionmentioning

confidence: 99%

Fast Holes, Slow Electrons, and Medium Control of Polaron Size and Mobility in the DA Polymer F8BT

et al. 2017

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The nature of electron and hole polarons on poly(9,9-di-n-hexylfluorenyl-2,7-diyl) (pF) and a copolymer poly [(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) has been studied by chemical doping, pulse radiolysis, charge modulation spectroscopy, quantum chemical calculations and microwave conductivity. While pF exhibits very similar behavior in all respects for the electron and the hole, this paper explores the hypothesis that the donor acceptor (push-pull) nature of F8BT will tend to localize charges.Optical spectra and quantum chemical calculations point to an electron localized on the thiadiazole unit in polar liquids, but becoming more delocalized as the solvent polarity decreases. Indeed, in the non-polar solvent benzene, the electron mobility is only 2.7 times lower than that of the hole, which conversely is shown to be delocalized in all environments and has a similar mobility to polarons on the homopolymer polyfluorene. Advantageous modifications to the optoelectronic properties of conjugated polymers, that come about by using alternating donor acceptor repeat units, have thus been shown to not significantly hinder charge transport despite the corrugated energy landscape along the backbone.

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Section: ■ Discussionmentioning

confidence: 99%

Fast Holes, Slow Electrons, and Medium Control of Polaron Size and Mobility in the DA Polymer F8BT

et al. 2017

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“…Other relevant works using molecular dynamics and Monte Carlo simulation (e.g., investigation on electron mobility properties) can be found elsewhere. [264][265][266][267] In a narrow sense, quantum chemistry refers to solving the Schrödinger equation based on several approximations using methods including the Hartree-Fock self-consistent method [267] and DFT. [268] First principles is considered as ab initio by some researchers, meaning doing quantum calculation by solving the Schrödinger equation only using generally accepted experimental statistics (e.g., electron weight, elementary charge, and light speed) without any assumptions or fitting parameters.…”

Section: Microscopic Space Charge Modeling: Molecular Simulationmentioning

confidence: 99%

“…Numerous studies have been focused on the charge trapping processes of EP and its composites using QCC. [258,259,[261][262][263]267] Li et al studied the properties of deep traps sites in EP/ graphene nanocomposites through DFT. [278] It was found that the horizontally applied electric field (parallel to the dielectric film) tended to drive electrons into lower energy levels, which led to the decrease of HOMO and the increase of LUMO, forming deep traps in the nanocomposites.…”

Section: Charge Trappingmentioning

confidence: 99%

Space Charge Behavior in Epoxy‐Based Dielectrics: Progress and Perspective

Liu

Xie

et al. 2022

Adv Elect Materials

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temperature and complex electric field conditions. [1][2][3] Epoxy resin (EP) is a class of polymer oligomers containing two or more epoxide groups based on organic compounds (e.g., aliphatic, alicyclic, and aromatic). As a prepolymer, EP shows excellent performance after its reaction with a curing agent to form an insoluble polymer with a 3D network structure. EP has desirable insulating characteristics, [4][5][6][7] heat resistance, [8] high mechanical strength, [9] low shrinkage, [10] chemical stability, and adhesive properties, which originate from its compact structure and tunable functional groups. The above mentioned outstanding performances, along with characteristics of easy processing and formula design flexibility, enable the extensive use of EP-based materials in power equipment and electronic devices [11] (Figure 1), including bar insulation and impregnating varnish in transformers, main insulation in dry-type bushings and wall bushings, insulator in gas-insulated switchgear (GIS) and gas-insulated transmission line (GIL), epoxy molding compound for integrated circuit (IC) packaging. It is noteworthy that EPs typically possess lower glass transition temperature (T g ) compared to other high-T g dielectric polymer substitutes used in microelectronic systems such as benzocyclobutene, [12] polyimide (PI), [13] and maleimide. [14] Besides high T g , high thermal conductivity and low coefficient of thermal expansion of EPs are always desired for their industrial applications, especially from an electronic packaging perspective. To date, considerable efforts have been made to improve the heat endurance and heat dissipation capabilities of EP-based dielectric materials by inorganic particle doping [15][16][17][18][19][20][21][22][23][24] and chemical modification. [25][26][27] Furthermore, EP is also an indispensable adhesive that is extensively used in power equipment. [28][29][30][31][32] Yet, potential reliability hazards may exist during the operation of power equipment and electronic devices, especially at high temperatures and under high voltage direct current (HVDC) application, one of which is the space charge accumulation in EP-based dielectric materials. [29,30,33,34] The accumulated space charge may cause deterioration/aging and even partial discharge or dielectric breakdown of dielectric materials. [35][36][37][38][39][40] Specifically, the extensive application of EP-based dielectric materials in HVDC transmission projects eagerly calls for relevant studies on the space charge behavior Epoxy-based dielectrics are extensively used in grid-connected energy systems and modern microelectronics as electrical insulation, adhesive, and packaging components. However, space charge accumulation in epoxy-based dielectrics is a foremost factor threatening device stability and lifespan, especially under conditions of high voltage direct current and high temperatures during long-term operation, and thus are investigated systematically. This article reviews the state-of-the-art progress in understanding and r...

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“…In this study, the charge trajectory was simulated by applying kinetic Monte Carlo (KMC) calculation 26 using the coordinates and the periodic boundary conditions used in the calculation of the molecules obtained in Section 2–1, and the intermolecular charge hopping rate obtained in Section 2–2. The diffusion constant was obtained from the charge trajectory by using the Einstein relation, and the mobility was obtained from the diffusion constant by the Einstein relation 24 …”

Section: Calculation Methodsmentioning

confidence: 99%

First‐principles based simulation of electron and hole transfer in PET oligmer

Sato

Kumada

Hidaka

2020

Elect Comm in Japan

Self Cite

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Recently, we have developed a first‐principles based multiscale modeling approach for studying carrier transport properties in polymeric dielectric, and have successfully modeled hole transfer in polyethylene (PE). In this study, in order to see if we can model carrier transport in more complex polymers, we have utilized the multiscale modeling method to simulate electron and hole transfer in polyethylene terephthalate (PET). The agreement between computed and experimental electron and hole mobilities in PET demonstrated the robustness of the modeling technique. The multiscale modeling approach enabled us to understand the microscopic origin of the carrier transport properties; unlike carrier transport in PE where the energetic disorder is dominated by the conformational disorder of the polymer chain, that in PET was strongly affected by the electrostatic disorder (disorder of the electrostatic potential due to surrounding environment). It is shown that this difference comes from the fact that (1) the charge localized region in PE chain is determined by the conformational disorder whereas that in PET is determined by the chemical structure of the polymer chain, and (2) PET chain has large local dipole compared to PE chain.

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Computational Study of Excess Electron Mobility in High-Pressure Liquid Benzene

Cited by 26 publications

References 83 publications

Fast Holes, Slow Electrons, and Medium Control of Polaron Size and Mobility in the DA Polymer F8BT

Fast Holes, Slow Electrons, and Medium Control of Polaron Size and Mobility in the DA Polymer F8BT

Space Charge Behavior in Epoxy‐Based Dielectrics: Progress and Perspective

First‐principles based simulation of electron and hole transfer in PET oligmer

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