TY - JOUR
T1 - Two Regioisomeric π-Conjugated Small Molecules
T2 - Synthesis, Photophysical, Packing, and Optoelectronic Properties
AU - Li, Yuxiang
AU - Lee, Dae Hee
AU - Lee, Joungphil
AU - Nguyen, Thanh Luan
AU - Hwang, Sungu
AU - Park, Moon Jeong
AU - Choi, Dong Hoon
AU - Woo, Han Young
N1 - Funding Information:
Y.L. and D.H.L. contributed equally to this work. This work was supported by the National Research Foundation (NRF) of Korea (2016M1A2A2940911, 2012M3A6A7055540, 2015R1A2A1A15055605, and 20100020209). The authors thank Gi Eun Park and Dr. Min Ju Cho for helping them to measure MS data and in helpful discussions. The authors also appreciate Prof. Kihang Choi and Min Wook Lee's assistance for 2D NMR measurement and analysis.
Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/9/6
Y1 - 2017/9/6
N2 - Two regioisomeric D1-A-D-A-D1 type π-conjugated molecules (1,4-bis{5-[4-(5-fluoro-7-(5-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole)]thiophen-2-yl}-2,5-bis(hexyldecyloxy)benzene (Prox-FBT) and 1,4-bis{5-[4-(6-fluoro-7-(5-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole)]thiophen-2-yl}-2,5-bis(hexyldecyloxy)benzene (Dis-FBT)) are synthesized, by controlling the fluorine topology to be proximal or distal relative to the central core. The different F geometries are confirmed by the 1H–1H nuclear Overhauer effect spectroscopy (NOESY). Clearly different optical, electrochemical, and thermal transition behaviors are obtained, i.e., stronger absorption, deeper valance band (by ≈0.2 eV), and higher melting/recrystallization temperatures (by 7–20 °C) are observed for Dis-FBT. The different intermolecular packing and unit cell structures are also calculated for the two regioisomers, based on the powder X-ray diffraction and 2D grazing-incidence wide-angle X-ray diffraction measurements. A tighter π–π packing with a preferential monoclinic face-on orientation is extracted for Dis-FBT, compared to Prox-FBT with bimodal orientations. Different topological structures significantly affect the electrical and photovoltaic properties, where Prox-FBT shows higher parallel hole mobility (2.3 × 10−3 cm2 V−1 s−1), but Dis-FBT demonstrates higher power conversion efficiency (5.47%) with a larger open-circuit voltage of 0.95 V (vs 0.79 V for Prox-FBT). The findings suggest that small changes in the topological geometry can affect the electronic structure as well as self-assembly behaviors, which can possibly be utilized for fine-adjusting the electrical properties and further optimization of optoelectronic devices.
AB - Two regioisomeric D1-A-D-A-D1 type π-conjugated molecules (1,4-bis{5-[4-(5-fluoro-7-(5-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole)]thiophen-2-yl}-2,5-bis(hexyldecyloxy)benzene (Prox-FBT) and 1,4-bis{5-[4-(6-fluoro-7-(5-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole)]thiophen-2-yl}-2,5-bis(hexyldecyloxy)benzene (Dis-FBT)) are synthesized, by controlling the fluorine topology to be proximal or distal relative to the central core. The different F geometries are confirmed by the 1H–1H nuclear Overhauer effect spectroscopy (NOESY). Clearly different optical, electrochemical, and thermal transition behaviors are obtained, i.e., stronger absorption, deeper valance band (by ≈0.2 eV), and higher melting/recrystallization temperatures (by 7–20 °C) are observed for Dis-FBT. The different intermolecular packing and unit cell structures are also calculated for the two regioisomers, based on the powder X-ray diffraction and 2D grazing-incidence wide-angle X-ray diffraction measurements. A tighter π–π packing with a preferential monoclinic face-on orientation is extracted for Dis-FBT, compared to Prox-FBT with bimodal orientations. Different topological structures significantly affect the electrical and photovoltaic properties, where Prox-FBT shows higher parallel hole mobility (2.3 × 10−3 cm2 V−1 s−1), but Dis-FBT demonstrates higher power conversion efficiency (5.47%) with a larger open-circuit voltage of 0.95 V (vs 0.79 V for Prox-FBT). The findings suggest that small changes in the topological geometry can affect the electronic structure as well as self-assembly behaviors, which can possibly be utilized for fine-adjusting the electrical properties and further optimization of optoelectronic devices.
KW - fluorine
KW - optoelectronics
KW - packing
KW - regioisomers
KW - topology
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U2 - 10.1002/adfm.201701942
DO - 10.1002/adfm.201701942
M3 - Article
AN - SCOPUS:85024114148
SN - 1616-301X
VL - 27
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 33
M1 - 1701942
ER -