Although the synthesis of two-dimensional (2D) layered MoS2 nanomaterials have been developing rapidly, there are many technical issues in preparing MoS2 quantum dots (QDs) with photoluminescence property. Herein, we design a facile colloidal chemical route to prepare photoluminescent MoS2 QDs using the ammonium tetrathiomolybdate ((NH4)2MoS4) as precursors and oleyl amine as reducing agent. The optical property and structure of as-prepared MoS2 QDs are investigated systematically. Resultant MoS2 QDs exhibit fluorescence (λmax=575 nm; quantum yield, 4.4%), spherical morphology with uniform thickness of ~3 nm and excitation-dependent PL phenomenon. Moreover, resultant MoS2 QDs show size-dependent tunable photoluminescence in wide visible region. With the help of the amphiphilic compound, resultant MoS2 QDs could be transferred from organic to aqueous phase. MoS2 QDs in aqueous solution have many advantages, such as good dispersion, low toxicity and photoluminescent property which make them possess promising applications in optoelectronic and biological fields. In this study, the 293T cells are used as a model to evaluate the fluorescence imaging of MoS2 QDs. The results confirm fluorescent signal appears in cytoplasm which demonstrates asprepared MoS2 QDs could be used as a probe for real-time optical cellular imaging.
Temperature measurements in biology and medical diagnostics, along with sensitive temperature probing of living cells, is of great importance; however, it still faces significant challenges. Herein, a novel "turn-on" carbon-dot-based fluorescent nanothermometry device for spatially resolved temperature measurements in living cells is presented. The carbon nanodots (CNDs) are prepared by a green microwave-assisted method and exhibit red fluorescence (λem =615 nm) with high quantum yields (15 %). Then, an on-off fluorescent probe is prepared for detecting glutathione (GSH) based on aggregation-induced fluorescence quenching. Interestingly, the quenched fluorescence could be recovered by increasing temperature and the CNDs-GSH mixture could behave as an off-on fluorescent probe for temperature. Thus, red-emitting CNDs can be utilized for "turn-on" fluorescent nanothermometry through the fluorescence quenching and recovery processes, respectively. We employ MC3T3-E1 cells as an example model to demonstrate the red-emitting CNDs can function as "non-contact" tools for the accurate measurement of temperature and its gradient inside a living cell.
All-inorganic perovskite quantum
dots (PQDs), which possess outstanding
photophysical properties, are regarded as promising materials for
optoelectronic applications. However, the poor light conversion efficiency
and severe stability problem hinder their widespread applications.
In this work, a novel encapsulation strategy is developed through
the in situ growth of CsPbX3 PQDs in presynthesized mesoporous
cerium-based metal organic frameworks (Ce-MOFs) and further silane
hydrolysis–encapsulation, generating stable CsPbX3@Ce-MOF@SiO2 composites with greatly enhanced light conversion
efficiency. Moreover, the simulation results suggest that the pore
boundary of Ce-MOFs has a strong waveguide effect on the incident
PQD light, constraining PQD light inside the bodies of Ce-MOFs and
suppressing reabsorption losses, thus increasing the overall light
conversion efficiency of PQDs. Meanwhile, the Ce-MOF@SiO2 protective shell effectively improves the stability by blocking
internally embedded PQDs from the harmful external environment. Further,
the obtained white-light-emitting diode shows an ultrahigh luminous
efficiency of 87.8 lm/W, which demonstrates their great potential
in optoelectronic applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.