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Indexed by:期刊论文

Date of Publication:2019-05-16

Journal:JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Included Journals:PubMed、SCIE、EI

Volume:10

Issue:10

Page Number:2428-2433

ISSN No.:1948-7185

Key Words:Electronic states; Excited states; Polycyclic aromatic hydrocarbons, Dimer cations; Energy thresholds; Excited electronic state; Higher efficiency; Internal conversions; Relaxed state; Time-scales; Vibrational cooling, Singlet fission

Abstract:Singlet fission directly from the upper excited vibrational and electronic states of cofacial perylene dimers, bypassing the relaxed state S-1, was detected within 50 fs. This process competes well with vibrational cooling in S-1 (4.7-7.0 ps) and S-2 -> S-1 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.