Structural, electronic, and linear optical properties of organic photovoltaic PBTTT-C14 crystal

Long Hua Li, Oleg Y. Kontsevoi, S. H. Rhim, Arthur J Freeman

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Poly(2,5-bis(3-tetradecylthiophen-2yl)thieno(3,2-b)thiophene) (PBTTT-C14) is an important electro-optical polymer, whose three-dimensional crystal structure is somewhat ambiguous and the fundamental electronic and linear optical properties are not well known. We carried out first-principles calculations to model the crystal structure and to study the effect of side-chains on the physical structure and electronic properties. Our calculations suggest that the patterns of side-chain has little direct effect on the valence band maximum and conduction band minimum but they do have impact on the bandgap through changing the π-π stacking distance. By examining the band structure and wave functions, we conclude that the fundamental bandgap of the PBTTT-C14 crystal is determined by the conduction band energy at the Q point. The calculations indicate that the bandgap of PBTTT-C14 crystal may be tunable by introducing different side-chains. The significant peak in the imaginary part of the dielectric function arises from transitions along the polymer backbone axis, as determined by the critical-point analysis and the large optical transition matrix elements in the direction of the backbone.

Original languageEnglish
Article number164503
JournalJournal of Chemical Physics
Volume138
Issue number16
DOIs
Publication statusPublished - Apr 28 2013

Fingerprint

Polymers
Transition Elements
Energy gap
Optical properties
Conduction bands
optical properties
Thiophenes
Crystals
conduction bands
Crystal structure
electronics
crystals
crystal structure
Optical transitions
polymers
Wave functions
Valence bands
thiophenes
optical transition
Electronic properties

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry
  • Medicine(all)

Cite this

Structural, electronic, and linear optical properties of organic photovoltaic PBTTT-C14 crystal. / Li, Long Hua; Kontsevoi, Oleg Y.; Rhim, S. H.; Freeman, Arthur J.

In: Journal of Chemical Physics, Vol. 138, No. 16, 164503, 28.04.2013.

Research output: Contribution to journalArticle

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