scholarly journals A general charge transport picture for organic semiconductors with nonlocal electron-phonon couplings

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weitang Li ◽  
Jiajun Ren ◽  
Zhigang Shuai
Keyword(s):  
Organic Semiconductors ◽  
Carrier Mobility ◽  
Numerical Study ◽  
Mean Free Path ◽  
Matrix Product ◽  
Electron Phonon Coupling ◽  
Transfer Integrals ◽  
The Matrix ◽  
Transfer Integral ◽  
Peierls Model

AbstractThe nonlocal electron-phonon couplings in organic semiconductors responsible for the fluctuation of intermolecular transfer integrals has been the center of interest recently. Several irreconcilable scenarios coexist for the description of the nonlocal electron-phonon coupling, such as phonon-assisted transport, transient localization, and band-like transport. Through a nearly exact numerical study for the carrier mobility of the Holstein-Peierls model using the matrix product states approach, we locate the phonon-assisted transport, transient localization and band-like regimes as a function of the transfer integral (V) and the nonlocal electron-phonon couplings (ΔV), and their distinct transport behaviors are analyzed by carrier mobility, mean free path, optical conductivity and one-particle spectral function. We also identify an “intermediate regime” where none of the established pictures applies, and the generally perceived hopping regime is found to be at a very limited end in the proposed regime paradigm.

Theoretical investigations of charge carrier transport in organic semiconductors of naphthalene bisimides N-substituted with alkoxyphenyl groups

2015 ◽  
Vol 93 (7) ◽  
pp. 740-748 ◽  
Author(s):  
Jun Yin ◽  
Kadali Chaitanya ◽  
Xue-Hai Ju
Keyword(s):  
Density Functional Theory ◽  
Charge Carrier ◽  
Organic Semiconductors ◽  
Carrier Mobility ◽  
Density Functional ◽  
Reorganization Energy ◽  
Charge Carrier Mobility ◽  
Transport Processes ◽  
Functional Theory ◽  
Transfer Integral

Three novel alkoxyphenyl N-substituted naphthalene bisimide derivatives, N,N′-bis(4-n-butoxyphenyl)-1,8:4,5-naphthalenetetracarboxylic (NBI1), N,N′-bis(4-n-hexyloxyphenyl)-1,8:4,5-naphthalenetetracarboxylic (NBI2), and N,N′-bis(4-n-octyloxyphenyl)-1,8:4,5-naphthalenetetracarboxylic (NBI3) as potential organic semiconductors, have been investigated using density functional theory calculations coupled with the incoherent charge-hopping model at the molecular and crystal levels. The calculated results demonstrate that the low-lying and delocalized LUMOs and larger adiabatic electron affinities of these compounds are beneficial to their stability when acting as n-type organic semiconductors. The reorganization energy and transfer integral can significantly influence the charge carrier mobility. The compounds featured with the small reorganization energy and large transfer integral have relatively high charge mobilities. The electron coupling among the dominant hopping pathways indicates that the charge-transport processes happen in the parallel dimer of neighboring molecules with π–π interaction. The investigation of the angle dependence of charge carrier mobility showed that both NBI1 and NBI3 crystals exhibit remarkable anisotropic charge transporting behaviors. The calculated absorption spectra by the time-dependent density functional theory revealed that the strongest absorption peaks in the visible region are assigned to the π → π* transition and these peaks are regulated by the transitions of HOMO → LUMO. The calculated electron mobilities of NBI1, NBI2, and NBI3 are 0.0365, 0.0312, and 0.0801 cm2 V–1 s–1, respectively, indicating that these compounds are suitable for n-type organic semiconductors.

scholarly journals Numerical Analysis of Viscoelastic Rotating Beam with Variable Fractional Order Model Using Shifted Bernstein–Legendre Polynomial Collocation Algorithm

2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Cundi Han ◽  
Yiming Chen ◽  
Da-Yan Liu ◽  
Driss Boutat
Keyword(s):  
Numerical Analysis ◽  
Fractional Order ◽  
Governing Equation ◽  
Numerical Solutions ◽  
Bernstein Polynomials ◽  
Matrix Product ◽  
Algebraic Equations ◽  
Rotating Beam ◽  
The Matrix ◽  
The Time Domain

This paper applies a numerical method of polynomial function approximation to the numerical analysis of variable fractional order viscoelastic rotating beam. First, the governing equation of the viscoelastic rotating beam is established based on the variable fractional model of the viscoelastic material. Second, shifted Bernstein polynomials and Legendre polynomials are used as basis functions to approximate the governing equation and the original equation is converted to matrix product form. Based on the configuration method, the matrix equation is further transformed into algebraic equations and numerical solutions of the governing equation are obtained directly in the time domain. Finally, the efficiency of the proposed algorithm is proved by analyzing the numerical solutions of the displacement of rotating beam under different loads.

Approaching isotropic transfer integrals in crystalline organic semiconductors

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Qijing Wang ◽  
Emilio J. Juarez-Perez ◽  
Sai Jiang ◽  
Mingfei Xiao ◽  
Jun Qian ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Transfer Integrals

Effect of Interfacial Properties on the Mechanical Behavior of Bone-Like Materials: A Numerical Study

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Behavior ◽  
Yield Behavior ◽  
Bonding Property ◽  
The Matrix ◽  
Bonding Properties ◽  
Superior Mechanical Properties

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.

The Hall Carrier Mobility of AgBiTe2-Ag2Te Composite

2001 ◽  
Vol 691 ◽  
Author(s):  
T. Sakakibara ◽  
Y. Takigawa ◽  
K. Kurosawa
Keyword(s):  
Electrical Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Hall Coefficient ◽  
Carrier Mobility ◽  
Matrix Phase ◽  
Second Phase ◽  
Temperature Range ◽  
The Matrix ◽  
Van Der Pauw

ABSTRACTWe prepared a series of (AgBiTe2)1−x(Ag2Te)x(0≤×≤1) composite materials by melt and cool down [1]. The Hall coefficient and the electrical conductivity were measured by the standard van der Pauw technique over the temperature range from 93K to 283K from which the Hall carrier mobility was calculated. Ag2Te had the highest mobility while the mobility of AgBiTe2was the lowest of all samples at 283K. However the mobility of the (AgBiTe2)0.125(Ag2Te)0.875composite material was higher than the motility of Ag2Te below 243K. It seems that a small second phase dispersed in the matrix phase is effective against the increased mobility.

Analytical and Numerical Study of Crushing of Syntactic Foams Under Uniaxial Compression

2008 ◽  
Author(s):  
Prabhakar Marur
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Numerical Study ◽  
Bulk Material ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Particulate Composites ◽  
Syntactic Foams ◽  
The Matrix ◽  
Crushing Behavior

Syntactic foams are a class of particulate composites made with hollow microspheres dispersed uniformly in a matrix. By the inclusion of hollow spheres in the matrix, the bulk mechanical properties are improved by limiting the bending of cell edges and localization of inelastic deformation, which is the cause of failure in the case of low-density foams. For the general class of cellular materials, several analytical and experimental methods are available in the literature to characterize the material. In the case of syntactic foams, relatively few methods exist for the computation of effective elastic properties and methods for analyzing the crush behavior of the syntactic foams are rather limited. In this research, the quasi-static crushing behavior of syntactic foam under uniaxial compression is investigated using analytical and numerical methods. To better understand the bulk behavior of syntactic foam, a micromechanical study is conducted to analyze the crushing of hollow spheres in dilute concentration. Initially the stress fields around dilute concentration are derived using continuum mechanics principles and subsequently a limit analysis is performed. To gain further insight into the deformation fields and deformations of cell walls leading to densification, a finite element (FE) analysis is performed. Assuming a periodic repetition of a representative volume of the material would correspond to the bulk material, axisymmetric and 3D finite element models are developed. The numerical computations are compared with the analytical results obtained in this study, and with experimental data reported in the literature. Using the FE models, a parametric study is conducted to investigate the influence of microsphere strength and elastic mismatch between the matrix and the inclusions on the crush behavior of syntactic foam.

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