Bisisoindigo–Benzothiadiazole Copolymers: Materials for Ambipolar and n-Channel OTFTs with Low Threshold Voltages
| Autor: | Timothy L. Kelly, Anindya Ganguly, Jenner H. L. Ngai, Arthur D. Hendsbee, Yuning Li, Raymond N. Bennett |
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| Rok vydání: | 2020 |
| Předmět: |
Organic electronics
chemistry.chemical_classification Materials science business.industry Ambipolar diffusion 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Acceptor 0104 chemical sciences Electronic Optical and Magnetic Materials Threshold voltage chemistry Electrode Materials Chemistry Electrochemistry Optoelectronics Molecular orbital 0210 nano-technology business HOMO/LUMO |
| Zdroj: | ACS Applied Electronic Materials. 2:2039-2048 |
| ISSN: | 2637-6113 |
| Popis: | The development of design strategies in both ambipolar and electron-conducting organic thin-film transistor (OTFT) materials is important for producing high-performance materials and devices in organic electronics. Isoindigo donor–acceptor polymers have been well studied as hole-conducting materials in OTFTs, while more electron-deficient, acceptor-rich isoindigo polymers have been underexplored. In this report, two common design strategies in isoindigo-based polymers, acceptor–acceptor polymers and core-expanded isoindigo structures, are combined to create copolymers of bisisoindigo, a core-expanded derivative of isoindigo, and electron-deficient benzothiadiazoles. These polymers exhibit the low energy lowest unoccupied molecular orbitals (LUMOs) required for electron transport and show ambipolar OTFT performance with hole and electron mobilities up to 4.0 × 10–3 and 1.4 × 10–3 cm2 V–1 s–1, respectively. Additionally, changing the source and drain contacts from Au to LiF/Al significantly lowered the threshold voltage due to improved alignment of the polymer and electrode energy levels. Comparisons of the optoelectronic properties between these polymers and previously reported bisisoindigo donor–acceptor polymers indicate that the increased acceptor strength lowers the frontier molecular orbital energies, while the dithienyl-benzothiadiazole unit impacts the film morphology by altering the shape of the polymer backbone. |
| Databáze: | OpenAIRE |
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