Regulating Charge-Transfer in Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution |
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Authors: | Dr Venkata Suresh Mothika Dr Papri Sutar Parul Verma Dr Shubhajit Das Prof Dr Swapan K Pati Prof Dr Tapas Kumar Maji |
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Institution: | 1. Molecular Materials Laboratory, Chemistry and Physics of, Materials Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064 India;2. Molecular Materials Laboratory, Chemistry and Physics of, Materials Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064 India
These authors contributed equally to this work.;3. Theoretical Sciences Unit (TSU), School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Banglaore, 560064 India |
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Abstract: | Bandgap engineering in donor–acceptor conjugated microporous polymers (CMPs) is a potential way to increase the solar-energy harvesting towards photochemical water splitting. Here, the design and synthesis of a series of donor–acceptor CMPs tetraphenylethylene (TPE) and 9-fluorenone (F) as the donor and the acceptor, respectively], F0.1CMP , F0.5CMP , and F2.0CMP , are reported. These CMPs exhibited tunable bandgaps and photocatalytic hydrogen evolution from water. The donor–acceptor CMPs exhibited also intramolecular charge-transfer (ICT) absorption in the visible region (λmax=480 nm) and their bandgap was finely tuned from 2.8 to 2.1 eV by increasing the 9-fluorenone content. Interestingly, they also showed emissions in the 540–580 nm range assisted by the energy transfer from the other TPE segments (not involved in charge-transfer interactions), as evidenced from fluorescence lifetime decay analysis. By increasing the 9-fluorenone content the emission color of the polymer was also tuned from green to red. Photocatalytic activities of the donor–acceptor CMPs ( F0.1CMP , F0.5CMP , and F2.0CMP ) are greatly enhanced compared to the 9-fluorenone free polymer ( F0.0CMP ), which is essentially due to improved visible-light absorption and low bandgap of donor–acceptor CMPs. Among all the polymers F0.5CMP with an optimum bandgap (2.3 eV) showed the highest H2 evolution under visible-light irradiation. Moreover, all polymers showed excellent dispersibility in organic solvents and easy coated on the solid substrates. |
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Keywords: | charge transfer conjugated polymers energy transfer hydrogen evolution photocatalysis |
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