Computational study on the Thieno[3,4-b]pyrazines and its derivatives based conducting polymers
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Date
2014-06
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Addis Ababa Universty
Abstract
The research in the (thieno[3,4-b]pyrazine, TP) π -conjugated molecules has become one
of the most interesting topics in the fields of chemistry. The use of low band gap materials
is a viable method for better harvesting of the solar spectrum and increasing its
efficiency. The control of the band gap of these materials is a research issue of ongoing
interest. In this work, the geometrical and electronic properties of (Thieno[3,4-
b]pyrazine, [TP]) based donor-acceptor conjugated oligomers were studied by the
density functional theory (DFT) at the B3LYP level with 6-31G (d,p) basis set from the
geometry optimization the inter-rings bonds are longer than normal double bonds but
shorter than the single bonds these indicate that the emerging of a quinoidal like
distortions as a result of oxidation. A low band gap will be expected in polymers
containing donor-acceptor (D - A) repeating units. The absorption spectra of a designed
low-band gap conjugated polymer has been studied using the TDDFT/B3LYP/6-31G.
Two main absorption peaks can be seen, the one largest in wavelength corresponding to
a HOMO to LUMO transition, except compound C1 and one involving higher order
excitations. The thermodynamic property calculations show that up on polymerization the
change in thermodynamic properties decreases. This decrease in change in
thermodynamic properties shows that the oxidized forms of the compound (C1) is
unstable with compare to other compounds.
Keyword/phrases: Thieno[3,4-b]pyrazine(TP), donor-acceptor, low-band gap,
optoelectronic, DFT, geometrical and electronic properties
Description
Keywords
Thieno[3,4-b]pyrazine(TP), Donor-acceptor, low-band gap, optoelectronic, DFT, Geometrical and electronic properties