We report the synthesis of a new low band gap planar polymer of poly(2,5-bis(2-decyltetradecyl)-3-(5-(dithieno[3,2-b:2′,3′-d]thiophen-2-yl)thieno[3,2-b]thiophen-2-yl)-6-(thieno[3,2-b]thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) (PTTDPP-DT-DTT) for use in organic thin film transistors (OTFTs). The polymer backbone is highly planar and well-conjugated, facilitating interchain stacking. The PTTDPP-DT-DTT-based OTFTs were fabricated and carrier mobilities were improved by using a binary solvent system: chloroform (CF):toluene (Tol), CF:chlorobenzene (CB), and CF:o-dichlorobenzene (DCB). The addition of higher boiling point solvents promoted film crystallinity with more edge-on orientations. Thus, the use of CF:DCB yielded the highest carrier mobility obtained among the devices tested. Thermal annealing further enhanced the mobility of the CF:DCB device. Atomic force microscopy images disclosed the most fibrous feature in the thermally annealed polymer film cast from CF:DCB solution. This work highlights that both the proper selection of a binary solvent and thermal annealing can manage film morphology of rigid planar conjugated polymer semiconductors effectively for high-performance OTFTs.
Bibliographical noteFunding Information:
This work was supported by the Ewha Womans University Research Grant of 2015, Korea Institute of Science and Technology (KIST) Internal Program, New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea Goverment Ministry of Trade, Industry & Energy (MTIE) ( 2011030010060 , 20133030000130 ), Center for Advanced Soft Electronics (CASE) under the Global Frontier Research Program ( NRF-2013M3A6A5073177 ), and Basic Science Research Program ( 2009-0083540 ) of the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology .
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All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Process Chemistry and Technology