Prospects for Organic Dye Nanoparticles - Advanced Fluorescence Reporters in Chemistry and Biology - page 299

DASPE-TFPB), respectively. The obtained solid precipitates were brightly
emissive whereas that of the native DASPE-I were almost nonemissive
(Fig. 7a ; the photo is taken under normal illumination and UV-light irradia-
tion). This indicates that, in the solid of the ion-pair species between DASPE +
and TPB (or TFPB ), concentration quenching is effectively suppressed,
and more importantly, these ion-pair complexes can generate fluorescent

Fig. 7 (a) Photograph of the solid-state DASPE-TFPB and DASPE-I. The upper and lower
images were obtained under normal-light and UV-light (365 nm) irradiation, respectively,
showing an intense emission from the solid-state DASPE-TFPB with excitation at 365 nm. (b)
Electron microscopy images of the prepared DASPE nanoparticle samples (average diameter
¼ 47 and 98 nm, respectively). (c) Photograph (two left-side vials with different nanoparticle
sizes) representing the highly emissive property of the DASPE nanoparticles. The aqueous
solution of DASPE-I ( right-side vial) showed almost no emission. (d) Absorption spectra of
DASPE-I in water and chloroform along with those of DASPE nanoparticles ( d av ¼ 47 and
98 nm) prepared using TFPB .(e) Fluorescence spectra of DASPE nanoparticles of d av ¼ 47

and 98 nm. Emission of the dye monomer in water is also shown. The nanoparticle exhibited
greater that 20-fold enhancement