The effects of oxygenation on the optical properties of dimethyl-dithienothiophenes: comparison between experiments and first-principles calculations

M F Raganato; V Vitale; F Della Sala; M Anni; R Cingolani; G Gigli; L Favaretto; G Barbarella; M Weimer; A Görling

doi:10.1063/1.1775782

The effects of oxygenation on the optical properties of dimethyl-dithienothiophenes: comparison between experiments and first-principles calculations

J Chem Phys. 2004 Aug 22;121(8):3784-91. doi: 10.1063/1.1775782.

Authors

M F Raganato¹, V Vitale, F Della Sala, M Anni, R Cingolani, G Gigli, L Favaretto, G Barbarella, M Weimer, A Görling

Affiliation

¹ National Nanotechnology Laboratory of INFM, Distretto Tecnologico, Universita degli Studi di Lecce, Via per Arnesano, I-73100 Lecce, Italy.

PMID: 15303947
DOI: 10.1063/1.1775782

Abstract

Modifications of the optical properties of dimethyl-dithienothiophenes due to the oxygen functionalization of the central sulfur atom are investigated. We have measured the absorption, photoluminescence (PL) and PL excitation spectra, the PL quantum efficiencies, and the PL decay times. These experimental results are interpreted and compared with first-principles time-dependent density-functional theory calculations, which predict, for the considered systems, excitation and emission energies with an accuracy of 0.1 eV. It is found that the oxygenation strongly changes optical and photophysical properties. These effects are related to the modifications of the energetically lowest-unoccupied molecular orbital and the energetically second highest occupied one, which change the relative position of the two lowest singlet and triplet excited states.