1. Soluble Diphenylhexatriene Dimers for Intramolecular Singlet Fission with High Triplet Energy
- Author
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Millington, Oliver, Montanaro, Stephanie, Leventis, Anastasia, Sharma, Ashish, Dowland, Simon A, Sawhney, Nipun, Fallon, Kealan J, Zeng, Weixuan, Congrave, Daniel G, Musser, Andrew J, Rao, Akshay, Bronstein, Hugo, Millington, Oliver [0000-0001-6787-8553], Fallon, Kealan J [0000-0001-6241-6034], Zeng, Weixuan [0000-0003-1577-9021], Musser, Andrew J [0000-0002-4600-6606], Rao, Akshay [0000-0003-4261-0766], Bronstein, Hugo [0000-0003-0293-8775], and Apollo - University of Cambridge Repository
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Colloid and Surface Chemistry ,34 Chemical Sciences ,3406 Physical Chemistry ,7 Affordable and Clean Energy ,General Chemistry ,Biochemistry ,Article ,Catalysis - Abstract
Funder: Ramsay Memorial Trust, Funder: Winton Programme for the Physics of Sustainability, Intramolecular singlet fission (iSF) facilitates single-molecule exciton multiplication, converting an excited singlet state to a pair of triplet states within a single molecule. A critical parameter in determining the feasibility of SF-enhanced photovoltaic designs is the triplet energy; many existing iSF materials have triplet energies too low for efficient transfer to silicon via a photon multiplier scheme. In this work, a series of six novel dimers based upon the high-triplet-energy, SF-active chromophore, 1,6-diphenyl-1,3,5-hexatriene (DPH) [E(T1) ∼ 1.5 eV], were designed, synthesized, and characterized. Transient absorption spectroscopy and fluorescence lifetime studies reveal that five of the dimers display iSF activity, with time constants for singlet fission varying between 7 ± 2 ps and 2.2 ± 0.2 ns and a high triplet yield of 163 ± 63% in the best-performing dimer. A strong dependence of the rate of fission on the coupling geometry is demonstrated. For optimized iSF behavior, close spatial proximity and minimal through-bond communication are found to be crucial for balancing the rate of SF against the reverse recombination process.
- Published
- 2023
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