S. Akimoto et al., DIMER FORMATION AND EXCITATION RELAXATION OF PERYLENE IN LANGMUIR-BLODGETT-FILMS, JOURNAL OF PHYSICAL CHEMISTRY B, 101(19), 1997, pp. 3753-3758
Steady-state and picosecond time-resolved fluorescence spectra of pery
lene have been measured in order to examine the dimer formation and th
e excitation relaxation in restricted geometries of Langmuir-Blodgett
(LB) films. In LB films, perylene forms two types of dimers, D-1 and D
-2, which are assigned to the dimers where two chromophores are partia
lly and fully overlapped, respectively. At the concentration of 0.05 m
ol %, only the monomer fluorescence is observed. As the concentration
is increased to 1 mol %, the excimer 1 fluorescence (from DI site) can
be seen in the time region after 40 ns. At a concentration higher tha
n 10 mol %, all three components including the excimer 2 fluorescence
(D-2) are observed from the early stage of time. Their contributions t
o the steady-state and the time-resolved fluorescence spectra are depe
ndent upon the concentration. The excitation transfer from M (monomer)
and D-1 sites to the D-2 Site occurs with a time constant of similar
to 50 ps at a concentration of 10 mol %, whereas it is similar to 10 p
s in the case of 50 mol %.