Synthesis, molecular and photovoltaic/transistor properties of heptacyclic ladder-type di(thienobenzo)fluorene-based copolymers
| Autor: | Zong-Liang Lin, Fong Yi Cao, Chun-Jen Su, Yen-Ju Cheng, Jhih-Yang Hsu, U-Ser Jeng, Chia Hao Lee, Yu Ying Lai |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Materials science Band gap 02 engineering and technology General Chemistry Polymer Fluorene 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Polymer solar cell 0104 chemical sciences Stille reaction chemistry.chemical_compound Crystallography chemistry Polymer chemistry Materials Chemistry Side chain Copolymer 0210 nano-technology HOMO/LUMO |
| Zdroj: | Journal of Materials Chemistry C. 4:11427-11435 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/c6tc04300c |
| Popis: | 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 CC 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. |
| Databáze: | OpenAIRE |
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