DFT and TD-DFT Study of Structure and Properties of Semiconductive Hybrid Networks Formed by Bismuth Halides and Different Polycyclic Aromatic Ligands

Y Belhocine,M Bencharif

doi:10.1155/2011/720231

Abstract

The structure and spectroscopic properties of polycyclic aromatic ligands of 2,3,6,7,10,11-hexakis (alkylthio) triphenylene (alkyl: methyl, ethyl, and isopropyl; corresponding to the abbreviations of the molecules: HMTT, HETT and HiPTT) were studied using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods with triple-zeta valence polarization (TZVP) basis set. It was shown that the type of functional theory used, Becke-Perdew (BP) and Leeuwen-Baerends (LB94) implemented in Amsterdam Density functional (ADF) program package, does not have essential influence on the geometry of studied compounds in both ground and excited states. However, significant differences were obtained for the band gap values with relativistic effects of the zero order regular approximation scalar corrections (ZORA) and LB94 functional seems to reproduce better the experimental optical band gap of these systems.

Highlights

Molecular conductors based on radical cations of tetrathiafulvalene (TTF)[1] and its derivatives have been of major interest in the last decades[2]
The experimental measurements of the electronic band gap of all compounds vary between 1.64 eV for the 2D network of 3-HMTT2BiBr3 to 2.98 eV for the isolated (0D) HMTT, suggesting that Bi-S and Bi-X bonds improve the electronic interactions rather than π-π stacks interactions between organic molecules
We have assessed the efficiency of different methods and functionals for calculating the optical band gaps

Summary

Introduction

Molecular conductors based on radical cations of tetrathiafulvalene (TTF)[1] and its derivatives have been of major interest in the last decades[2]. Structure of the organic ligands with atom labelling Do the solid-state electronic properties depend on nature of bond coordination of Bi-S and Bi-X of such systems. A large number of density functional theory (DFT) studies have treated excited state properties based on the time-dependent (TD) method.

Results

Conclusion