36
F. Ito
1.0
0.8
0.6
0.4
0.2
0.0
Intensity / a.u.
700
600
500
400
Wavelength / nm
0.5 s
10 s
20 s
30 s
40 s
50 s
60 s
70 s
80 s
90 s
91 s
92 s
93 s
94 s
95 s
96 s
97 s
98 s
99 s
100 s
101 s
102 s
103 s
104 s
105 s
110 s
120 s
0 s
25 s
32 s
34 s
35 s
40 s
55 s
(a)
(b)
Fig. 2.6 a Fluorescence images of a droplet of BF 2 DBMb in 1,2-dichloroethane during evaporation under 365 nm UV irradiation. The droplet diameter is approximately 5 mm. b Changes in
fluorescence spectra of BF 2 DBMb in 1,2-dichloroethane during solvent evaporation. Reprinted by
permission from Macmillan Publishers Ltd.: Ref. [19], copyright 2016
assembling can be isolated or frozen by the polymer matrix, the dynamics of which
revealing the formation of the crystal from the monomer state via the amorphous
state of BF 2 DBMb. These findings are supported by the XRD results in polymer
films. The fluorescence excitation spectra of BF 2 DBMb in PMMA films indicate
the exciton splitting of the band, suggesting the formation of H- and J-aggregates
with increasing concentration. Based on the band splitting, the average number of
aggregated molecules was estimated to be 12 molecules.
Next, we attempted to measure the fluorescence change during evaporative crystallization from solution. The detection of the molecular assembling through the
fluorescence changes can be expected, particularly liquid-like clusters, such as the
amorphous aggregated state. Figure 2.6a shows the fluorescence images during the
solvent evaporation from 3.1 × 10
–2 mol dm
−3 BF 2 DBMb in a 1,2-dichloroethane
droplet, and the movie of which is shown in the supporting information [19]. In this
trial, the time origin is set to after the complete focusing of the CCD camera, which
describes the reason for the indicated time difference between the movie and the
spectral change described below. At a time of 0 s, the fluorescence color is purple.
The emission color changes to orange from the edge of droplet after 25 s. With the
elapse of time, the emission color transiently becomes orange all over the droplet at
F. Ito
1.0
0.8
0.6
0.4
0.2
0.0
Intensity / a.u.
700
600
500
400
Wavelength / nm
0.5 s
10 s
20 s
30 s
40 s
50 s
60 s
70 s
80 s
90 s
91 s
92 s
93 s
94 s
95 s
96 s
97 s
98 s
99 s
100 s
101 s
102 s
103 s
104 s
105 s
110 s
120 s
0 s
25 s
32 s
34 s
35 s
40 s
55 s
(a)
(b)
Fig. 2.6 a Fluorescence images of a droplet of BF 2 DBMb in 1,2-dichloroethane during evaporation under 365 nm UV irradiation. The droplet diameter is approximately 5 mm. b Changes in
fluorescence spectra of BF 2 DBMb in 1,2-dichloroethane during solvent evaporation. Reprinted by
permission from Macmillan Publishers Ltd.: Ref. [19], copyright 2016
assembling can be isolated or frozen by the polymer matrix, the dynamics of which
revealing the formation of the crystal from the monomer state via the amorphous
state of BF 2 DBMb. These findings are supported by the XRD results in polymer
films. The fluorescence excitation spectra of BF 2 DBMb in PMMA films indicate
the exciton splitting of the band, suggesting the formation of H- and J-aggregates
with increasing concentration. Based on the band splitting, the average number of
aggregated molecules was estimated to be 12 molecules.
Next, we attempted to measure the fluorescence change during evaporative crystallization from solution. The detection of the molecular assembling through the
fluorescence changes can be expected, particularly liquid-like clusters, such as the
amorphous aggregated state. Figure 2.6a shows the fluorescence images during the
solvent evaporation from 3.1 × 10
–2 mol dm
−3 BF 2 DBMb in a 1,2-dichloroethane
droplet, and the movie of which is shown in the supporting information [19]. In this
trial, the time origin is set to after the complete focusing of the CCD camera, which
describes the reason for the indicated time difference between the movie and the
spectral change described below. At a time of 0 s, the fluorescence color is purple.
The emission color changes to orange from the edge of droplet after 25 s. With the
elapse of time, the emission color transiently becomes orange all over the droplet at