Singlet Fission from Upper Excited Electronic States of Cofacial Perylene Dimer

Wenjun Ni; Gagik G Gurzadyan; Jianzhang Zhao; Yuanyuan Che; Xiaoxin Li; Licheng Sun

doi:10.1021/acs.jpclett.9b00717

Singlet Fission from Upper Excited Electronic States of Cofacial Perylene Dimer

J Phys Chem Lett. 2019 May 16;10(10):2428-2433. doi: 10.1021/acs.jpclett.9b00717. Epub 2019 Apr 30.

Authors

Wenjun Ni¹, Gagik G Gurzadyan¹, Jianzhang Zhao², Yuanyuan Che², Xiaoxin Li¹, Licheng Sun^{1

3}

Affiliations

¹ State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis , Dalian University of Technology , 116024 Dalian , China.
² State Key Laboratory of Fine Chemicals , Dalian University of Technology , 116024 Dalian , China.
³ Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health , KTH Royal Institute of Technology , 10044 Stockholm , Sweden.

PMID: 31025867
DOI: 10.1021/acs.jpclett.9b00717

Abstract

Singlet fission directly from the upper excited vibrational and electronic states of cofacial perylene dimers, bypassing the relaxed state S₁, was detected within 50 fs. This process competes well with vibrational cooling in S₁ (4.7-7.0 ps) and S₂ → S₁ internal conversion (380 fs). The singlet fission has the energy threshold E = 3.06 eV. Other competitive relaxation processes are excimer and dimer cation formation on an ultrafast time scale. Excitation to higher energy levels (4.96 eV) leads to a higher efficiency of singlet fission.