title: Combined UMC- DFT prediction of electron-hole coupling in unit cells of pentacene crystals.
abstract: Pentacene is an organic semiconductor that draws special attention from the scientific community due to the high mobility of its charge carriers. As electron-hole interactions are important aspects in the regard of such property, a computationally inexpensive method to predict the coupling between these quasi-particles is highly desired. In this work, we propose a hybrid methodology of combining Uncoupled Monte Carlo Simulations (UMC) and Density functional Theory (DFT) methodologies to obtain a good compromise between computational feasibility and accuracy. As a first step in considering a Pentacene crystal, we describe its unit cell: the Pentacene Dimer. Because many conformations can be encountered for the dimer and considering the complexity of the system, we make use of UMC in order to find the most probable structures and relative orientations for the Pentacene-Pentacene complex. Following, we carry out electronic structure calculations in the scope of DFT with the goal of describing the electron-hole coupling on the most probable configurations obtained by UMC. The comparison of our results with previously reported data on the literature suggests that the methodology is well suited for describing transfer integrals of organic semiconductors. The observed accuracy together with the smaller computational cost required by our approach allows us to conclude that such methodology might be an important tool towards the description of systems with higher complexity.
authors.affiliation: Department of Electrical Engineering, Universidade de Brasília, CP04455, Brasília, DF, CEP 70919-970, Brazil.
authors.forename: Luciano Almeida
authors.initials: LA
authors.lastname: Leal
authors.affiliation: Department of Electrical Engineering, Universidade de Brasília, CP04455, Brasília, DF, CEP 70919-970, Brazil.
authors.forename: Rafael Timóteo
authors.initials: RT
authors.lastname: de Souza Júnior
authors.affiliation: Institute of Physics, 70.919-970, Brasília, Brazil.
authors.forename: Antonio Luciano
authors.initials: AL
authors.lastname: de Almeida Fonseca
authors.affiliation: Institute of Physics, 70.919-970, Brasília, Brazil.
authors.forename: Luiz Antonio
authors.initials: LA
authors.lastname: Ribeiro Junior
authors.affiliation: Department of Electrical Engineering, Universidade de Brasília, CP04455, Brasília, DF, CEP 70919-970, Brazil.
authors.forename: Stefan
authors.initials: S
authors.lastname: Blawid
authors.affiliation: Institute of Physics, 70.919-970, Brasília, Brazil.
authors.forename: Demetrio Antonio
authors.initials: DA
authors.lastname: da Silva Filho
authors.affiliation: Institute of Physics, 70.919-970, Brasília, Brazil. wiliam@unb.br.
authors.forename: Wiliam Ferreira
authors.initials: WF
authors.lastname: da Cunha
keywords: Charge transport; Conjugated polymers; DFT; Electron coupling; Pentacene; Uncoupled monte carlo simulations