Highly sensitive detection of discrete absorption and B-type delayed fluorescence of dibenzanthracene in PMMA.
High resolution S0 --> Sn and T1 --> Tn electronic absorptions and B-type delayed fluorescence of 1,2,7,8-dibenzanthracene in polymethylmethacrylate (PMMA) were experimentally observed by flash and laser flash photolysis technique. Dibenzanthracene molecules were excited in a two-step process. In the first step, an excited singlet is created, which undergoes intersystem crossing to triplet state, then T-T absorption creates an excited triplet dibenzanthracene molecule, which returns to the first excited singlet level by intersystem crossing. The re-created first excited singlet of dibenzanthracene decays back to the ground state by emitting B-type of delayed fluorescence, which was observed at the same emission band of prompt (normal) fluorescence, and R-, E-, P-types of delayed fluorescences. For normal fluorescence, S1 state is decaying to S0 ground state. For E- and P-type of delayed fluorescences, T1 state is decaying to S0 via S1 state, and for B-type of delayed fluorescence, T2 state is decaying to S0 via S1 state.
Bayrakçeken
Fuat
F
Department of Electronics Engineering, Yeditepe University, Kayisdagi, Istanbul 81120, Turkey. bayrakf@yeditepe.edu.tr
D000042:Absorption; D001551:Benz(a)Anthracenes / Q000737:chemistry*; D005453:Fluorescence; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
D001551:Benz(a)Anthracenes; C016365:dibenzanthracenes; D019904:Polymethyl Methacrylate