Zeng, TaoMellerup, SorenYang, DengtaoWang, XiangWang, SuningStamplecoskie, Kevin2020-04-032020-04-032018T. Zeng, S. Mellerup, D.-T. Yang, X. Wang, S. Wang, K. Stamplecoskie. “Identifying (BN)2-pyrene as a new class of singlet fission chromophores: significance of azaborine substitution.” Journal of Physical Chemistry Letters 2018, 9, 2919-2927.https://doi.org/10.1021/acs.jpclett.8b01226https://hdl.handle.net/10315/37170Singlet fission converts one photoexcited singlet state to two triplet excited states and raises photoelectric conversion efficiency in photovoltaic devices. However, only a handful of chromophores have been known to undergo this process, which greatly limits the application of singlet fission in photovoltaics. We hereby identify a recently synthesized diazadiborine-pyrene ((BN)2-pyrene) as a singlet fission chromophore. Theoretical calculations indicate that it satisfies the thermodynamics criteria for singlet fission. More importantly, the calculations provide a physical chemistry insight into how the BN substitution makes this happen. Both calculation and transient absorption spectroscopy experiment indicate that the chromophore has a better absorption than pentacene. The convenient synthesis pathway of the (BN)2-pyrene suggests an in situ chromophore generation in photovoltaic devices. Two more (BN)2-pyrene isomers are proposed as singlet fission chromophores. This study sets a step forward in the cross-link of singlet fission and azaborine chemistry.enArticlehttps://pubs.acs.org/doi/pdf/10.1021/acs.jpclett.8b01226