CeF3, CeF3:Tb3+, and CeF3:Tb3+/LaF3 (core/shell) nanoparticles were prepared by the polyol method
and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray
photoelectron spectra (XPS), UV−vis absorption spectra, photoluminescence (PL) spectra, and lifetimes.
The results of XRD indicate that the obtained CeF3, CeF3:Tb3+, and CeF3:Tb3+/LaF3 (core/shell)
nanoparticles crystallized well at 200 °C in diethylene glycol (DEG) with a hexagonal structure. The
TEM images illustrate that the CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of
7 nm. The growth of the LaF3 shell around the CeF3:Tb3+ core nanoparticles resulted in an increase of
the average size (11 nm) of the nanopaticles as well as in a broadening of their size distribution. These
nanocrystals can be well-dispersed in ethanol to form clear colloidal solutions. The colloidal solutions of
CeF3 and CeF3:Tb3+ show the characteristic emission of Ce3+ 5d−4f (320 nm) and Tb3+
5D4−7FJ (J =
6−3, with 5D4−7F5 green emission at 542 nm as the strongest one) transitions, respectively. The emission
intensity and lifetime of the CeF3:Tb3+/LaF3 (core/shell) nanoparticles increased with respect to those of
CeF3:Tb3+ core particles. This indicates that a significant amount of nonradiative centers existing on the
surface of CeF3:Tb3+ nanoparticles can be eliminated by the shielding effect of LaF3 shells. Finally, the
energy transfer from Ce3+ to Tb3+ was investigated in CeF3:Tb3+ nanoparticles in detail.
Integrating emotional cues from different senses is critical for adaptive behavior. Much of the evidence on cross-modal perception of emotions has come from studies of vision and audition. This research has shown that an emotion signaled by one sense modulates how the same emotion is perceived in another sense, especially when the input to the latter sense is ambiguous. We tested whether olfaction causes similar sensory modulation of emotion perception. In two experiments, the chemosignal of fearful sweat biased women toward interpreting ambiguous expressions as more fearful, but had no effect when the facial emotion was more discernible. Our findings provide direct behavioral evidence that social chemosignals can communicate emotions and demonstrate that fear-related chemosignals modulate humans' visual emotion perception in an emotion-specific way--an effect that has been hitherto unsuspected.
A direct white-light metal-organic framework (MOF), [AgL](n) x nH(2)O (1, L = 4-cyanobenzoate), obtained by the reaction of deprotonated 4-cyanobenzoic acid and AgNO(3) in water, was found to exhibit tunable yellow-to-white photoluminescence by variation of excitation light. Interestingly, the close pure white emission of 1 has CIE-1931 chromaticity coordinates of (0.33, 0.34) when excited by 349-nm UV light, which is compatible to the light output of the deep UV LED.
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