Excimer, a configurational mixing between Frenkel exciton and charge-transfer resonance states, is typically regarded as a trap state that hinders desired energy or charge-transfer processes in artificial molecular assemblies. However, in recent days, the excimer has received much attention as a functional intermediate in the excited-state dynamics such as singlet fission or charge-separation processes. In this work, we show that the relative contribution to charge-transfer resonance of the excimer state in a bay-substituted perylene bisimide dimer cyclophane can be modulated by dielectric properties of the solvents employed. Solvent-dependent time-resolved fluorescence and absorption measurements reveal that an enhancement of charge-transfer resonance in the excimer state is reflected by incomplete symmetry-breaking charge-separation processes from the structurally relaxed excimer state by means of dipolar solvation processes in the high dielectric environment.
Bibliographical noteFunding Information:
The work at Yonsei University was supported the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (2016R1E1A1A01943379). The quantum-mechanical calculations were supported by the National Institute of Supercomputing and Network (NISN)/ Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (KSC-2018-CRE-0051). The research at the Uni- versity of Würzburg has been supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the research unit FOR 1809.
Copyright © 2019 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry