https://scholars.lib.ntu.edu.tw/handle/123456789/467650
標題: | Synthesis, molecular and photovoltaic/transistor properties of heptacyclic ladder-type di(thienobenzo)fluorene-based copolymers | 作者: | Lee, C.-H. Lai, Y.-Y. Cao, F.-Y. Hsu, J.-Y. Lin, Z.-L. Jeng, U.-S. Su, C.-J. Cheng, Y.-J. YU-YING LAI |
公開日期: | 2016 | 卷: | 4 | 期: | 48 | 起(迄)頁: | 11427-11435 | 來源出版物: | Journal of Materials Chemistry C | 摘要: | We present a facile synthesis method to make a new ladder-type heptacyclic dithienobenzofluorene (DTBF) framework, where the central 2,7-fluorene unit is covalently fastened with two external thiophenes via two C=C bridges. A dieneyne-containing precursor undergoes DBU-induced double benzannulation to regiospecifically introduce two solubilizing 2-octyldodecyl side chains at 5,10-positions of DTBF. The rigid and coplanar Br-DTBF monomer with sufficient solubility was copolymerized with 5,6-difluoro-4,7-bis(5-(trimethylstannyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (Sn-DTFBT) and 5,10-bis(5-(trimethylstannyl)thiophen-2-yl)naphtho[1,2-c:5,6-c′]bis([1,2,5]thiadiazole) (Sn-DTNT) via Stille coupling to furnish two donor-acceptor copolymers, PDTBFFBT and PDTBFNT, respectively. Their thermal, optical, electrochemical, molecular stacking and photovoltaic properties are investigated. PDTBFNT has a higher molecular weight, smaller optical and electrochemical band gaps, and stronger solid-state packing than PDTBFFBT. DFT calculations were carried out to gain insight into the electronic and structural properties of DTBF and its derivatives. Bulk heterojunction solar devices with the ITO/ZnO/polymers:PC71BM/MoO3/Ag configuration were fabricated. By adding 5 vol% diphenyl ether (DPE) as an additive, PDTBFNT:PC71BM and PDTBFFBT:PC71BM devices achieved the power conversion efficiencies of 5.22% and 2.68%, respectively. The superior efficiency of PDTBFNT over PDTBFFBT is attributed to the better LUMO energy alignment between PDTBFNT and PC71BM and the face-on π-stacking of PDTBFNT in the active layer. Moreover, PDTBFNT exhibited a higher field-effect transistor hole mobility of 1.90 × 10−2 cm2 V−1 s−1 than PDTBFFBT with a value of 3.96 × 10−3 cm2 V−1 s−1. © The Royal Society of Chemistry. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/467650 | DOI: | 10.1039/c6tc04300c | SDG/關鍵字: | Energy gap; Field effect transistors; Heterojunctions; Hole mobility; Organic compounds; Sulfur compounds; Tin; Bulk heterojunction; DFT calculation; Donor-acceptor copolymers; Electronic and structural properties; Facile synthesis; Molecular stacking; Photovoltaic property; Power conversion efficiencies; Ladders |
顯示於: | 高分子科學與工程學研究所 |
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