A dual-emission probe to detect moisture and water in organic solvents based on green-Tb³⁺ post-coordinated metal–organic frameworks with red carbon dots

Abstract

Using p-phenylenediamine as a precursor, p-carbon dots (p-CDs) with strong red-light emission were encapsulated into a metal-organic framework (MOF) followed by introduction of green light-emitting Tb to form a two-color light-emitting hybrid (Tb@p-CDs/MOF). The as-prepared fluorescent-functionalized MOF not only maintained the excellent optical properties of p-CDs and Tb to give strong emission, but also had good chemical and physical properties. The chosen p-CDs were aggregated readily in water, which led to only very weak photoluminescence, whereas the opposite effect was noted in the organic solvents ethanol, dimethylformamide and cyclopropane. Therefore, the as-prepared hybrid showed different color light emission in water or organic solvents, and acted as a ratiometric and colorimetric fluorescent probe to detect water content in organic solvents. Moreover, this hybrid also served as a ratiometric luminescent sensor for detection of relative humidity (RH): the ratio of light intensity at 545 nm to that at 605 nm increased linearly with increasing RH from 33.0% to 85.1% in the atmosphere.

Sensing and photocatalytic properties of nanosized Cu(I)CN organotin supramolecular coordination polymer based on pyrazine

“…Generally, there are two main reasons for sensing phenomena: photoinduced electron transfer or resonance energy transfer, or both . The quenching mechanism may be due to photoinduced electron transfer between the excited SCP 1 and the guest solvent molecules.…”

“…The quenching mechanism may be due to photoinduced electron transfer between the excited SCP 1 and the guest solvent molecules. The luminescence quenching caused by acetone molecules may be explained in terms of the photoinduced electron transfer theory . The carbonyl group in acetone can form hydrogen‐bond interactions with the fused hexagonal rings of SCP 1 and, during excitation, electron transfer from SCP 1 to acetone leads to luminescence quenching.…”

“…Generally, there are two main reasons for sensing phenomena: photoinduced electron transfer or resonance energy transfer, or both. [67,68] The quenching mechanism may be due to photoinduced electron transfer between the excited SCP1 and the guest solvent molecules. The luminescence quenching caused by acetone molecules may be explained in terms of the photoinduced electron transfer theory.…”

“…The luminescence quenching caused by acetone molecules may be explained in terms of the photoinduced electron transfer theory. [67,68] The carbonyl group in acetone can form hydrogen-bond interactions with the fused hexagonal rings of SCP1 and, during excitation, electron transfer from SCP1 to acetone leads to luminescence quenching. On the other hand, the luminescence quenching may be due to physical interaction between the Pyz ligand used to construct SCP1 and acetone where the energy absorbed by the ligand is transferred to acetone molecules, resulting in the luminescence quenching of SCP1 according to resonance energy transfer mechanism.…”

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

“…[26][27][28][29] Carbon dots (CDs), however, as a new class of quantum-sized and wavelength dependent materials, with unique optical and electrical properties, are much less studied in combination with Ln-MOFs (e.g. [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. [30][31][32] They are superior to the traditional quantum dots and dye materials in terms of their chemical inertness.…”