with a small feature at shorter wavelength stemming from the tb-DXP. The band
looks identical under excitation at λ ¼ 490 nm. The excitation spectrum, observed at
λ ¼ 680 nm, shown as blue dash-dot line, follows the absorption spectrum drawn as
blue solid line. The intensity of the short-wavelength contribution, mainly stemming
from the absorption of DMPOPOP, is larger than expected. This is probably caused
by the scattering contribution at short wavelength, which is much lower in the range
of emission of the HR acceptor [16]. Alternative ways for preparing interesting
photonic antenna composites base on ZL as a host have been reported
[79, 206]. Bañuelos et al. prepared a four-dye antenna composite base on ZL as a
host [80].
The first report on a time-space and spectrally resolved characterization of a
photonic antenna was published in 2001 [50]. It was achieved in the laboratory of
R. Pansu, ENS Cachan, and was made possible thanks to the favorable properties of
dye2,dye1-ZL antenna composite. Measurements of similar type became then soon
common standard; see, e.g., [162, 166, 178]. We explain the early experiment by
means of Fig. 29, where part (a) shows the size and organization of the composite.
The length of the ZL crystal is seen in the electron microscopy image; it amounts to
2,600 nm. The host was in a first step filled with Ox
+ using cation exchange. The
so-prepared composite was then dried under vacuum. The DMPOPOP, which we
name DMP in the figure in order to shorten the name, was then added under vacuum
conditions using the double ampoule method reported in [54]. The scanning confocal fluorescence microscopy images from left to right show the emission along the
channels for DMP upon excitation at 330–385 nm and observed through a polarizer
oriented parallel to the long axis, as indicated by the white double arrow, while the
image in the middle was observed when the polarizer was turned into vertical
position, as indicated by the yellow double arrow. The image seen on the right
was observed without a polarizer upon excitation of the Ox
+ at 545–580 nm. The
intensity profile on the left of Fig. 29a was observed when scanning the emission at
470 nm along the crystal axis, upon excitation at 320 nm. The profile in the middle
was observed when monitoring the emission at 610 nm after excitation at 320 nm,
while the profile on the right was seen when the sample was excited at 490 nm. The
data show that the organization of the dyes inside the crystal corresponds to the
scheme seen in (a). They also beautifully illustrate the energy transfer from the DMP
to the Ox
+
, and they show that the energy migration length of excited Ox
+ is not
sufficient to fill the 2,600-nm-long crystals homogeneously, in accordance with
theoretical considerations [151]. The fact that the ETDM of DMP and of Ox
+ is
oriented nearly perpendicular to each other inside a channel is optimal for these
experiments, but it is of course not optimal for efficient FRET from DMP to Ox
+
.
The hexagonal structure of the host has, however, as a consequence that each
channel is surrounded by six neighbor channels which still allow for important
FRET, as has already been explained [151] more explicitly in Fig. 8 of
[15]. Figure 29b reports the first part of the Luminescence dynamics. The blue line
represents the fluorescence decay of DMP, observed on a crystal that contains only
this dye, hence DMP-ZL, excited at 320 nm and observed at 470 nm. The average
lifetime was 1.78 ns. The decay of Ox
+ can be observed at 600 nm on a single DMP,
Guests in Nanochannels of Zeolite L
53
looks identical under excitation at λ ¼ 490 nm. The excitation spectrum, observed at
λ ¼ 680 nm, shown as blue dash-dot line, follows the absorption spectrum drawn as
blue solid line. The intensity of the short-wavelength contribution, mainly stemming
from the absorption of DMPOPOP, is larger than expected. This is probably caused
by the scattering contribution at short wavelength, which is much lower in the range
of emission of the HR acceptor [16]. Alternative ways for preparing interesting
photonic antenna composites base on ZL as a host have been reported
[79, 206]. Bañuelos et al. prepared a four-dye antenna composite base on ZL as a
host [80].
The first report on a time-space and spectrally resolved characterization of a
photonic antenna was published in 2001 [50]. It was achieved in the laboratory of
R. Pansu, ENS Cachan, and was made possible thanks to the favorable properties of
dye2,dye1-ZL antenna composite. Measurements of similar type became then soon
common standard; see, e.g., [162, 166, 178]. We explain the early experiment by
means of Fig. 29, where part (a) shows the size and organization of the composite.
The length of the ZL crystal is seen in the electron microscopy image; it amounts to
2,600 nm. The host was in a first step filled with Ox
+ using cation exchange. The
so-prepared composite was then dried under vacuum. The DMPOPOP, which we
name DMP in the figure in order to shorten the name, was then added under vacuum
conditions using the double ampoule method reported in [54]. The scanning confocal fluorescence microscopy images from left to right show the emission along the
channels for DMP upon excitation at 330–385 nm and observed through a polarizer
oriented parallel to the long axis, as indicated by the white double arrow, while the
image in the middle was observed when the polarizer was turned into vertical
position, as indicated by the yellow double arrow. The image seen on the right
was observed without a polarizer upon excitation of the Ox
+ at 545–580 nm. The
intensity profile on the left of Fig. 29a was observed when scanning the emission at
470 nm along the crystal axis, upon excitation at 320 nm. The profile in the middle
was observed when monitoring the emission at 610 nm after excitation at 320 nm,
while the profile on the right was seen when the sample was excited at 490 nm. The
data show that the organization of the dyes inside the crystal corresponds to the
scheme seen in (a). They also beautifully illustrate the energy transfer from the DMP
to the Ox
+
, and they show that the energy migration length of excited Ox
+ is not
sufficient to fill the 2,600-nm-long crystals homogeneously, in accordance with
theoretical considerations [151]. The fact that the ETDM of DMP and of Ox
+ is
oriented nearly perpendicular to each other inside a channel is optimal for these
experiments, but it is of course not optimal for efficient FRET from DMP to Ox
+
.
The hexagonal structure of the host has, however, as a consequence that each
channel is surrounded by six neighbor channels which still allow for important
FRET, as has already been explained [151] more explicitly in Fig. 8 of
[15]. Figure 29b reports the first part of the Luminescence dynamics. The blue line
represents the fluorescence decay of DMP, observed on a crystal that contains only
this dye, hence DMP-ZL, excited at 320 nm and observed at 470 nm. The average
lifetime was 1.78 ns. The decay of Ox
+ can be observed at 600 nm on a single DMP,
Guests in Nanochannels of Zeolite L
53