Molecular modelling of ground- and excited-states vibrations in organic conducting devices: hexakis(n-hexyloxy)triphenylene (HAT(6)) as case study
No Thumbnail Available
Date
2010-03-26
Journal Title
Journal ISSN
Volume Title
Publisher
CSIRO Publishing
Abstract
In order to gain insight into fundamental aspects of organic photocell materials, we have calculated ground and excited electronic-state structures and molecular vibrations for an isolated HAT6 molecule (hexakis(n-hexyloxy)triphenylene). Excited-state calculations are carried out using time-dependent density functional theory and frequencies are evaluated analytically using coupled perturbed Kohn–Sham equations. These model calculations have been validated against new infrared and ultraviolet data on HAT6 in solution. The main allowed valence excitation, having the largest oscillator strength, is chosen for the structural and vibrational investigations. Comparison with the ground-state vibrational dynamics reveals surprisingly large spectral differences. In addition, the alkoxy tails, which are usually considered to play only a structural role, are clearly involved in the molecular vibrations and the structural distortion of the excited electronic state compared with the ground state. The tails may play a more important role in charge separation, transport and excited-state relaxation than was previously thought. In this case, chemical modification of the tails would allow vibrational and related properties of organic photocell materials to be tailored. © 2010, CSIRO Publishing
Description
Keywords
Molecular models, Conductor devices, Organic matter, Excited states, Ground states, Vibrational states
Citation
Zbiri, M., Johnson, M. R., Haverkate, L., Mulder, F. M., & Kearley, G. J. (2010). Molecular modelling of ground- and excited-states vibrations in organic conducting devices: hexakis(n-hexyloxy)triphenylene (HAT(6)) as case study. Australian Journal of Chemistry, 63(3), 388-395. doi:10.1071/CH09459