Showing papers by "Bing Yan published in 2016"

A postsynthetically modified MOF hybrid as a ratiometric fluorescent sensor for anion recognition and detection

Abstract: A metal–organic framework (MOF), MIL-125(Ti)-NH2, and its derivatives MIL-125(Ti)-AM and MIL-125(Ti)-AM-Eu are synthesized. The structure and morphology of the obtained-samples are characterized by some characterization methods such as XRD, SEM, IR and XPS. Under solvothermal conditions, MIL-125(Ti)-NH2 shows typical truncated bipyramid morphology, and the terminal amino group can be further modified by covalent postsynthetic modification (PSM). The functional MOFs exhibit excellent photoluminescence features, and they have been designed to be a ratiometric fluorescent sensor (IL/IEu) for sensitively detecting phosphate and oxalate, which are important substances in an organism. In our research, we also investigate the lifetime and quantum yield of MIL-125(Ti)-AM-Eu, and analyze the changes of that which are caused by various anions. Finally, we utilize the luminescence ratio (IL/IEu) and the quantum yield to establish an orthogonal pattern for anion recognition. MIL-125(Ti)-AM-Eu can be used to detect some unknown anions, and we find that the detector has high sensitivity and stability, and can be used repeatedly.

Novel core–shell structure microspheres based on lanthanide complexes for white-light emission and fluorescence sensing

Abstract: A series of new core–shell structure materials based on lanthanide complexes [H2NMe2]3[Ln(dpa)3] (Ln = Eu, Tb, Sm, Dy, Nd, and Yb; [H2NMe2]+ = dimethylamino cation; dpa = 2-dipicolinate) and silica microspheres has been prepared under solvothermal conditions. Electron microscopy reveals that the nanosized materials SiO2@Ln-dpa are spherical with a narrow size distribution and a [H2NMe2]3[Ln(L)3] coating was generated on the surface of silica microspheres successfully. The core–shell structure materials exhibit excellent optical performance. The white-light-emitting material SiO2@(Dy:Eu)-dpa has a potential application in the development of a white-light device, as a result of the fact that its CIE chromaticity coordinate is very close to that of pure white. Then, we selected SiO2@Eu-dpa as a representative sample for sensing experiments. Eventually, we found that the core–shell structure sensors are highly selective and sensitive for acetone and Cu2+ cations. The detection of Cu2+ in the human body is an important issue. Interestingly, the core–shell structure materials display better selectivity and higher sensitivity than the pure lanthanide complexes in sensing Cu2+ and the value of the quenching effect coefficient has increased by more than 20%.

Lanthanides post-functionalized indium metal-organic frameworks (MOFs) for luminescence tuning, polymer film preparation and near-UV white LED assembly.

Abstract: A class of hybrid materials based on indium 2,2′-bipyridine-5,5′-dicarboxylate metal–organic frameworks, In(OH)bpydc, was synthesized by postsynthetic introduction with lanthanide ions (Eu3+, Tb3+ and Sm3+) The structure, thermal stability, morphology and more detailed information about these materials were characterized by XRD, DSC, BET, FTIR, SEM and so forth The further study of luminescent properties in detail showed that these compounds possess characteristic emission, and the In-MOF–Eu maintains different colors of light from blue-green to red under different excitation wavelengths (excited at 400 nm to 320 nm), which includes the near-white light region (the color coordinates are X = 034, Y = 036) It is a remarkable fact that the trend of ligand-central emission is opposite to that of the characteristic emission of Eu3+ Moreover, a kind of thin film and assembled white light near-UV LED based on the optically lanthanide-functionalized MOFs was prepared in order to extend their potential applications; both of them lead to desirable white light (X = 034, Y = 036; X = 035, Y = 037) In addition, the matrix does not affect the white luminescence

Barcoded materials based on photoluminescent hybrid system of lanthanide ions-doped metal organic framework and silica via ion exchange

Abstract: A multicolored photoluminescent hybrid system based on lanthanide ions-doped metal organic frameworks/silica composite host has potential in display and barcode applications. By controlling the stoichiometry of the lanthanides via cation exchange, proportional various lanthanide ions are successfully introduced into metal organic frameworks, whose emission intensity is correspondingly proportional to its amount. The resulting luminescent barcodes depend on the lanthanide ions ratios and compositions. Subsequently, the lanthanide ions located in the channels of metal organic frameworks are protected from any interaction with the environment after the modification of silica on the surface. The optical and thermal stability of the hybrid materials are improved for technological application.