TY - JOUR
T1 - Charge Delocalization in Oligomers of Poly(2,5-bis(3-Alkylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT)
AU - Zhang, Yuexing
AU - Steyrleuthner, Robert
AU - Bredas, Jean Luc
N1 - Funding Information:
This work has been supported by King Abdullah University of Science and Technology (KAUST). We acknowledge the KAUST IT Research Computing Team for providing computational and storage resources and thank Dr. Cheng Zhong, Dr. Haitao Sun, and Dr. Bradley D. Rose for stimulating discussions.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/5/12
Y1 - 2016/5/12
N2 - We investigate theoretically charge delocalization in radical cations, i.e., positive polarons, formed on oligomer chains of poly(2,5-bis(3-Alkylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT). We use nonempirically tuned range-separated density functionals (TRS-DFT), including LC-?PBE, LC-BLYP, and ?B97XD. We consider the evolution with oligomer length of the molecular geometric and electronic structures, optical absorption features, and spin densities. The TRS-DFT results indicate that a positive polaron can delocalize ideally over some 10 thiophene rings when the backbone is nonplanar and up to 14 rings for a backbone forced to be completely planar. Interestingly, up to six polarons can coexist side-by-side in a hexamer (which contains 24 thiophene rings), which is consistent with the highest degrees of doping (oxidation) experimentally achievable in polythiophene derivatives.
AB - We investigate theoretically charge delocalization in radical cations, i.e., positive polarons, formed on oligomer chains of poly(2,5-bis(3-Alkylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT). We use nonempirically tuned range-separated density functionals (TRS-DFT), including LC-?PBE, LC-BLYP, and ?B97XD. We consider the evolution with oligomer length of the molecular geometric and electronic structures, optical absorption features, and spin densities. The TRS-DFT results indicate that a positive polaron can delocalize ideally over some 10 thiophene rings when the backbone is nonplanar and up to 14 rings for a backbone forced to be completely planar. Interestingly, up to six polarons can coexist side-by-side in a hexamer (which contains 24 thiophene rings), which is consistent with the highest degrees of doping (oxidation) experimentally achievable in polythiophene derivatives.
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U2 - 10.1021/acs.jpcc.6b02378
DO - 10.1021/acs.jpcc.6b02378
M3 - Article
AN - SCOPUS:84971421847
VL - 120
SP - 9671
EP - 9677
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 18
ER -