A multi-agent quantum Monte Carlo model for charge transport: Application to organic field-effect transistors

Abstract

We have developed a multi-agent quantum Monte Carlo model to describe the spatial dynamics of multiple majority charge carriers during conduction of electric current in the channel of organic field-effect transistors. The charge carriers are treated by a neglect of diatomic differential overlap Hamiltonian using a lattice of hydrogen-like basis functions. The local ionization energy and local electron affinity defined previously map the bulk structure of the transistor channel to external potentials for the simulations of electron- and hole-conduction, respectively. The model is designed without a specific charge-transport mechanism like hopping- or band-transport in mind and does not arbitrarily localize charge. An electrode model allows dynamic injection and depletion of charge carriers according to source-drain voltage. The field-effect is modeled by using the source-gate voltage in a Metropolis-like acceptance criterion. Although the current cannot be calculated because the simulations have no time axis, using the number of Monte Carlo moves as pseudo-time gives results that resemble experimental I/V curves.

Charge Transport in Organic Materials: Norm-Conserving Imaginary Time Propagation with Local Ionization Energy as the External Potential

“…These local properties represent an approximation in their present form, as they are strictly speaking not pure potentials but also contain a kinetic-energy contribution. We, however, have previously used them as potential hypersurfaces for a multiagent quantum Monte Carlo model for charge transport with some success to simulate an organic self-assembled monolayer system. , The simulated charge-carrier pathway densities found in this work agree with the ones calculated for the same system using the Monte Carlo technique. Using these 3D-energy maps as external potentials in the Hamilton operator allows the interaction of charge carriers with a complicated quantum mechanical system to be represented as simple scalar potentials embedded in three-dimensional space.…”

Local Electron Attachment Energy and Its Use for Predicting Nucleophilic Reactions and Halogen Bonding

“…It should be recognized that EA L ( r ) has successfully been used in a number of applications, including as a descriptor in QSAR analysis for drug design and for the calculation of charge-transport properties of organic-field transistors. − On the contrary, the use of EA L ( r ) in the analysis of chemical reactivity has been relatively sparse, which potentially can be traced to some of the issues discussed above.…”

Simulation of charge transport in organic semiconductors: A time-dependent multiscale method based on nonequilibrium Green's functions

“…This method was previously applied to study charge transport through DNA [6,7,11,12], and it has recently been extended to account for charge relaxation and electric field effects [8]. Here, we apply the methodology in a different setting to study charge transport in significantly larger organic structures, in particular C 60 -based SAMs used in FETs [13,14] (cf. Fig.…”