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Title: Electronic, vibrational, and charge-transport properties of benzothienobenzothiophene–TCNQ co-crystals
The electronic, vibrational, and charge-transport properties of a series of benzothieno-benzothiophene (BTBT)–F m TCNQ ( m = 0, 2, 4) and diC n BTBT–F m TCNQ ( n = 8, 12; m = 0, 4) donor–acceptor (DA) co-crystals have been investigated by means of density functional theory calculations. The electronic-structure calculations predict wide conduction bands and small effective masses for electrons along the DA stacking directions. The results indicate that the increase in the number of F atoms on the acceptor molecules results in an increase of superexchange couplings along the DA stacks, while the addition of the alkyl side chains results in a decrease of through-space transfer integrals between neighboring stacks. Time-dependent density functional theory calculations of the optical properties describe the lowest two optical transitions as having a charge-transfer character and being related to the two electronic coupling pathways that contribute to the superexchange couplings. The results also indicate that the ionicity parameter in the diC n BTBT–F m TCNQ cocrystals is somewhat larger than in the BTBT analogues. Overall, we find that DFT calculations based on periodic boundary conditions are a reliable tool to estimate the ionicity parameter in DA cocrystals.  more » « less
Award ID(s):
2023497 1708147
PAR ID:
10280360
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Materials Chemistry Frontiers
Volume:
4
Issue:
12
ISSN:
2052-1537
Page Range / eLocation ID:
3623 to 3631
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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