https://scholars.lib.ntu.edu.tw/handle/123456789/425110
Title: | Band gap engineering via controlling donor-acceptor compositions in conjugated copolymers | Authors: | Hung, Ying Chieh CHI-YANG CHAO CHI-AN DAI WEI-FANG SU SHIANG-TAI LIN |
Issue Date: | 17-Jan-2013 | Publisher: | AMER CHEMICAL SOC | Journal Volume: | 117 | Journal Issue: | 2 | Start page/Pages: | 690 | Source: | Journal of Physical Chemistry B | Abstract: | Varying composition of π-donor/acceptor moieties has been considered as an effective strategy for fine-tuning of the electronic properties of D-A conjugated copolymers. In this study, the change of optoelectronic properties with the change of donor/acceptor ratios is investigated on the basis of first-principles density functional calculations. Copolymers containing moieties of similar π-electron donating and/or accepting capabilities, e.g., thiophene (T)-methoxythiophene (OT), exhibit a linear dependence of electronic properties (especially, HOMO/LUMO, band gap, and bandwidth) on the D/A content. In contrast, for strong D/A contrast systems, e.g., thiophene (T)-thienopyrazine (TP), the electronic properties vary nonlinearly with D/A compositions. However, when the block size of one parent monomer in a strong D/A contrast system is fixed, the variation of electronic properties shows a remarkable linear correlation against D/A compositions. We found that the deviation of electronic properties from a linear composition dependence is dominated by the strength of orbital interactions between D and A. Weak orbital interactions between D and A moieties tend to lead to a nonlinear composition dependence. Our results provide useful insights for band gap tuning through the adjustment of D/A compositions in D-A conjugated copolymers. © 2012 American Chemical Society. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/425110 | ISSN: | 15206106 | DOI: | https://api.elsevier.com/content/abstract/scopus_id/84872572590 10.1021/jp3090974 |
Appears in Collections: | 材料科學與工程學系 |
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