Actas de congresos
The Electronic And Optical Properties Of Oligo(trans-1,2-di(2-thienyl)-1,3- Butadiene): A Theoretical Study
Registro en:
International Journal Of Quantum Chemistry. , v. 108, n. 13, p. 2499 - 2506, 2008.
207608
10.1002/qua.21816
2-s2.0-52449131813
Autor
Marcal N.
Laks B.
Institución
Resumen
In the present work we investigated the theoretical electronic structure of poly(frans-1,4-di(2-thienyl)-1,3-butadiene) (PTB) and determined the optical properties of its neutral and doped oligomers. Geometrical optimizations were at the semiempirical level by using the Austin method 1 (AMI). The band structure of π electrons regarding to the neutral PTB polymer was obtained by using a tight-binding Hamiltonian. The densities of electronic states (DOS) for neutral and doped copolymers were calculated by using the negative factor counting technique. The spatial charge distribution of the oligomeric chain was also analyzed. The energy of the electronic transitions and their associated oscillator strength values were calculated for the neutral, double, and single charged oligomers to determine the UV-vis absorption spectra. The calculations were performed using the intermediate neglect of differential overlap Hamiltonian in combination with the single configuration-interaction technique in order to include correlation effects. The band gap obtained in the PTB was about 2.101 eV for the optics absorption and 1.73 eV for the DOS. The bipolaron states appear in the gap, about 0.57 eV and 0.48 eV below and above the conduction and valence bands, respectively. When the dopants concentration is increased the DOS showed that the energy gap tends to vanish, which may lead to semiconductor-metal transition. © 2008 Wiley Periodicals, Inc. 108 13 2499 2506 Onoda, M., Iwasa, T., Kawai, T., Yoshino, K., (1991) J Phys Soc Jpn, 60, p. 3768 Onoda, M., Iwasa, T., Kawai, T., Yoshino, K., (1993) Synth Met, 55, p. 1614 Brédas, J.L., Silbey, R., Conjugated Polymers (1991) The Novel Science and Technology of Highly Conducting and Nonlinear Optically Active Materials, , Kluwer: Dordrecht Roncali, J., (1992) Chem Rev, 92, p. 711 Marçal, N., Laks, B., (2005) Int J Quantum Chem, 103, p. 617 Onoda, M., Iwasa, T., Kawai, T., Yoshino, K., (1991) J Phys D: Appl Phys, 24, p. 2076 Brédas, J.L., Chance, R.R., Silbey, R., (1982) Phys Rev B, 26, p. 5843 Brédas, J.L., Themans, B., Andre, J.M., (1983) Phys Rev B, 27, p. 7827 Marçal, N., Laks, B., (2006) Int J Quantum Chem, 106, p. 2723 Stewart, J.J.P., (1989) J Comput Chem, 10, p. 209 Hong, S.Y., Maynick, D.S., (1992) J Chem Phys, 96, p. 5497 Dean, P., (1959) Phys Soc, 73, p. 413. , London Ladik, J., Seel, M., Otto, P., Bakhshi, A.K., (2003) Chem Phys, pp. 1986-2108 Ridley, J., Zener, M., (1976) Theor Chim Acta, 42, p. 223 Cornil, J., Beljonne, D., Brédas, J.L., (1995) J Chem Phys, 103, p. 842 Doretto, R.L., Laks, B., (2002) J Chem Phys, 117, p. 5437 Schimidt, M.W., Baldridge, K.K., Boatz, J.A., Elbert, S.T., Gordon, M.S., Jensen, J.H., Koseki, S., Montgomery, J.A., (1993) J Comput Chem, 14, p. 1347 Herrema, J.K., Wildernan, J., van Bolhuis, F., Hadziioannou, G., (1993) Synth Met, 60, p. 239 Marçal, N., Laks, B., (2003) Int J Quantum Chem, 95, p. 230 Lavarda, F.C., Santos, M.C., Galvão, D.S., Laks, B., (1994) Phys Rev, 49, p. 979