Dual-Emission of Lanthanide Metal–Organic Frameworks Encapsulating Carbon-Based Dots for Ratiometric Detection of Water in Organic Solvents

Abstract

Nitrogen and sulfur codoped carbon-based dots (N,S-CDs) with strong blue light emission are encapsulated into red light-emitting europium metal-organic frameworks (Eu-MOFs) to form two color light-emitting nanohybrids (Eu-MOFs/N,S-CDs). In organic solvents, the encapsulated N,S-CDs are aggregated and confined in the cavities of the Eu-MOFs, exhibiting only a very weak photoluminescence (PL) signal. Therefore, the nanohybrids show red light emission of the Eu-MOFs. Contrarily, when the Eu-MOFs/N,S-CDs are dispersed in water, the encapsulated N,S-CDs are released into solution while the red light emission of the Eu-MOFs is quenched due to the effect of O-H oscillators. The nanohybrids are used as the probe for the water content in organic solvents. Take ethanol as an example; as the water content is increased from 0.2 to 30%, the nanoprobe provides distinguishable PL color change. The ratio of light intensity at 420 nm to that at 623 nm (I420/I623) increases linearly with increasing water content in the range from 0.05 to 4% with a low detection limit of 0.03%.

Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide

“…In addition, we can easily exclude the impact from other oxidants like HNO 3 , KClO 3 , FeCl 3 , and NaClO from the result of the absorption ratio of A 595 to A 555 . Hence, the dual-mode nanosensors demonstrated in this paper may be very promising in the high selectivity of the determination due to the synergistic effect of the two independent detection methods [30–33]. Furthermore, we have measured the response time of the fluorometric change upon the addition of H 2 O 2 and found that the fluorescence decreases after injecting H 2 O 2 and is kept stable at about 3.3 s (Additional file 1: Figure S14).

Fig.

…”

Designed Synthesis of Multiluminescent Materials Using Lanthanide Metal‐Organic Frameworks and Carbon Dots as Building‐Blocks

“…[31] As the result, the π→π* absorption band centred at 250 nm in the CDs is observed at 260 nm in the composite. As compared with the CDs, covalent binding of the CDs to the EuW-MOF leads to the red shift.…”

“…Due to the quenching effect on the CDs emission, this composite can also sense acetonitrile. [30][31][32] They are superior to the traditional quantum dots and dye materials in terms of their chemical inertness. materials are much easier processed for their integration in existing devices.…”

“…[37][38][39][40] A few examples of CDs@MOFs composites were reported so far. Currently, there is an increasing interest in sensing of inorganic ions [30] and toxic organic molecules [31,32] using luminescent composite materials. [43] We reported recently on achieving high proton conductivity and the electro-optical sensing in a series of cyanide-bridged lanthanide-based MOFs (abbreviated as LnM-MOFs) which have porous flexible structures.…”

Ratiometric fluorescence detection of superoxide anion based on AuNPs‐BSA@Tb/GMP nanoscale coordination polymers

“…The O 2 •− should be kept constant under normal conditions . Once the body releases excessive O 2 •− , it will lead to the peroxidation of body lipid and induces cancer, progressive neurodegenerative diseases, cardiovascular disease and hepatitis . Thus, it is very important to obtain real‐time analysis and detection of O 2 •− .…”