Release Time:2019-10-12  Hits:

Indexed by: Journal Article

Date of Publication: 2019-05-16

Journal: JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Included Journals: EI、SCIE、PubMed

Volume: 10

Issue: 10

Page Number: 2428-2433

ISSN: 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.