Synthesis and properties of the conjugated polymers with indenoindene and benzimidazole units for organic photovoltaics |
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| Authors: | Joo Young Shim Byoung Hoon Lee Suhee Song Heejoo Kim Ju Ae Kim Il Kim Kwanghee Lee Hongsuk Suh |
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| Institution: | 1. Department of Chemistry and Chemistry, Institute for Functional Materials, Pusan National University, Busan 609‐735, Korea;2. Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500‐712, Korea;3. The WCU Center for Synthetic Polymer Bioconjugate Hybrid Materials, Department of Polymer Science and Engineering, Pusan National University, Busan 609‐735, Korea |
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| Abstract: | A new electron deficient unit, dimethyl‐2H‐benzimidazole (MBI), and dihydroindeno2,1‐a]indene (ININE) moiety as electron‐rich unit were coupled to synthesize the conjugated polymers containing electron donor–acceptor pair for organic photovoltaics. ININE, MBI, and thiophene (or bithiophene) units were incorporated using Stille and Suzuki polymerization to generate poly(2,7‐(5,5,10,10‐tetrakis(2‐ethylhexyl)‐5,10‐dihydro‐ indeno2,1‐a]indene)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2,2‐dimethyl‐2H‐benzimidazole)) (PININEDTMBIs) (or PININEBBTMBIs). In MBI, the sulfur at 2‐position of 2,1,3‐benzothiadiazole (BT) unit was replaced with dialkyl‐substituted carbon, whereas keeping the 1,2‐quinoid form, to improve the solubility of the polymers. The field‐effect hole mobility of PININEBBTMBI was 3.2 × 10?4 cm2/Vs which was improved as compared to that of PININEDTMBI (2.7 × 10?5 cm2/Vs) caused by the introduction of bithiophene units. In case of the most efficient polymer, PININEBBTMBI, the device with the configuration of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene) (PEDOT):polystyrene sulfonate (PSS)/polymer:PC71BM(1:4 w/w)/Al, annealed at 100 °C for 10 min demonstrated a open circuit voltage of 0.78 V, a short‐circuit current density of 6.66 mA/cm2, and a fill factor of 0.41, leading to the power conversion efficiency of 2.11%, under white‐light illumination (AM 1.5 G, 100 mW/cm2). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 |
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| Keywords: | conjugated polymer copolymerization synthesis dihydroindeno[2 1‐a]indene 2H‐benzimidazole |
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