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Handbook of Ecomaterials || Electrochemical Synthesis of Coordination Compounds of Lanthanides: Effective Luminophores
摘要： The problems of electrochemical synthesis of complex compounds of lanthanides with organic acids are discussed. It was shown that the resulting complex compounds are thermally stable and can be used as effective luminophores.
关键词： Electrochemical synthesis,Luminescence,Lanthanides
更新于2025-09-09 09:28:46
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Design and control luminescence of Li2ZnGe3O8:Cr3+ in NIR ? region by cationic regulation
摘要： Li2ZnGe3O8:Cr3+ deep-red phosphor is synthesized, and the excitation spectrum ranges from 250 nm to 640 nm, and the emission peak locates at 713nm. In order to obtain NIR light, Mg2+/Ca2+/Sr2+/Ba2+ ions were introduced into Li2ZnGeO8:Cr3+. The emission spectra ?rstly show a blue shift and then present an obvious red shift by tuning the Zn/Mg ratio. A common e?ect between the crystal ?eld splitting and the nephelauxetic e?ect makes it possible to blue shift, and the red shift is ascribed to the reduced site symmetry around some Cr3+ ions caused by the disorder. In addition, the emission spectra have a red shift when Zn2+ is substituted by Ca2+, Sr2+ or Ba2+, which is also a common e?ect between the crystal ?eld splitting and the nephelauxetic e?ect. As a results, the luminescence materials realize the regulation from deep red to near-infrared light by increasing the doping ionic (Ca2+, Sr2+, and Ba2+) radii.
关键词： Phosphor,Li2ZnGe3O8:Cr3+,NIR ? region,Cationic regulation,Luminescence
更新于2025-09-09 09:28:46
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Near-infrared excited cooperative upconversion in luminescent Ytterbium(ΙΙΙ) bioprobes as light-responsive theranostic agents
摘要： Near-infrared (NIR) Ytterbium(III) complexes namely [Yb(dpq)(DMF)2Cl3] (1), [Yb(dppz)(DMF)2Cl3] (2), [Yb(dpq)(ttfa)3] (3) and [Yb(dppz)(ttfa)3] (4) based on photosensitizing antenna: dipyrido-[3,2-d:2’,3’-f]-quinoxaline (dpq), dipyrido-[3,2-a:2′,3′-c]-phenazine (dppz) and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Httfa), were designed as NIR bioimaging agents utilizing cooperative upconversion luminescence (CUCL) of Yb(III). Their structures, detailed photophysical properties, biological interactions, photo-induced DNA cleavage, NIR photocytotoxicity and cellular internalization and bioimaging properties were examined. Discrete mononuclear complexes adopt a seven-coordinated {LnN2O2Cl3} mono-capped octahedron (1, 2) and eight-coordinated {LnN2O6} distorted square antiprism geometry (3, 4) with bidentate N, N-donor dpq, dppz and O,O-donor ttfa ligands. The designed Yb(III) probes (3, 4) having advantages of dual sensitizing antennae (dpq/dppz and Httfa) to modulate the desirable optical properties in NIR region for bioimaging in biologically transparent window and light-responsive intracellular damage with spatiotemporal control. The lack of inner-sphere water (q = 0), remarkable photostability, large Stokes’ shifts, presence of energetically rightly poised ligand 3T states allows efficient energy transfer (ET) to the emissive 2F5/2 state of Yb(III). The unique cooperative upconversion luminescence (CUCL) of Yb(III) was observed in 1-4 in the visible blue region (λem = 490 nm) upon NIR excitation at 980 nm, makes them special candidates for NIR-to-visible or NIR-to-NIR cellular imaging probes. The CUCL property of Yb(III) were observed in the discrete mononuclear complexes both in solid state and solution. We elegantly utilized this remarkable property of Yb(III) for cellular imaging application for the first time to the our knowledge including potential uses in CUC/multiphoton excitation microscopy. The complexes exhibit significant binding propensity to DNA, HSA and BSA (K ~ 105 M-1). They effectively cleave supercoiled (SC) DNA to its nicked circular (NC) form at 365 nm via photoredox pathways. The cellular uptake studies evidently displayed cytosolic and nuclear localization of the complexes. Finally, the capability of Yb(III) complexes usage for PDT were demonstrated through significant near-IR photocytotoxicity at 980 nm CW laser. The results depicted here offers an intelligent strategy towards developing light-responsive highly photostable Yb(III) probes for NIR theranostic application in the biologically transparent phototherapeutic window.
关键词： Cooperative upconversion luminescence,NIR photocytotoxicity,NIR cellular imaging,Phototherapeutic,NIR excitation,Ytterbium
更新于2025-09-09 09:28:46
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Highly-efficient, Chemically-stable, UV/blue Light Excitable Biluminescent Security Ink to Combat Counterfeiting
摘要： A strategy has been demonstrated to design a biluminescent security ink using Eu(TTA)3Phen (ETP) and fluorescein for protecting the currency and other essential documents viz. passport, bank cheque, certificates against counterfeiting. Biluminescent security ink exhibits strong red and green emission under 367 and 445 nm excitations, respectively. As it is quite challenging to prepare a material that possesses two prominent (green and red) and distinguishable colors upon excitation with two separate LEDs sources, emitting at different wavelengths, the biluminescent security ink would be hard to counterfeit as compared to the existing luminescent security ink that exhibits single color under UV light exposure. To check its feasibility for security application the patterns printed out using biluminescent security ink were kept under a hot and humid atmosphere for 150 days. Also, the ETP and fluorescein fluorophores were exposed to UV light for a prolonged time, which do not show any sign of deterioration in their luminescence intensities. Furthermore, to check their chemical stability printed patterns were also exposed to chemicals which have potential to wiped-out ink viz. detergent, ethanol, acetone, and sodium hypochlorite (bleach) solution and noticed that it is well stable against these chemicals. Because of the reasons mentioned above and easy availability of 367 and 445 nm LEDs at low cost, authors believe that the application of this biluminescent security ink can trigger to realize the full potential of this advanced security feature in detecting fake currency.
关键词： luminescence,lanthanide,security ink,anticounterfeiting,fluorescein
更新于2025-09-09 09:28:46
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Determination of Handedness in a Single Chiral Nanocrystal via Circularly Polarized Luminescence
摘要： The occurrence of biological homochirality is attributed to symmetry breaking mechanisms which are still debatable. Studies of symmetry breaking require tools for monitoring the population ratios of individual chiral nano-objects, such as molecules, polymers or nanocrystals. Moreover, mapping their spatial distributions may elucidate on their symmetry breaking mechanism. While luminescence is preferred for detecting single particle chirality due to its high signal to noise ratio, the typical low optical activity of chromophores limits its applicability. Here, we report on handedness determination of single chiral lanthanide based luminescent nanocrystals with a total photon count of 2×104. Due to the large emission dissymmetry we could determine the handedness of individual particles using only a single circular polarization component of the emission spectrum, without polarization modulation. A machine learning algorithm, trained to several spectral lineshape features, enabled us to determine and spatially map the handedness of individual nanocrystals with high accuracy and speed. This technique may become invaluable in studies of symmetry breaking in chiral materials.
关键词： chiroptical activity,circularly polarized luminescence,lanthanide nanocrystals,single-particle spectroscopy
更新于2025-09-09 09:28:46
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Enhanced Quenching Effect of Neonicotinoid Pesticides on Time-Resolved Terbium Luminescence in Presence of Surfactants
摘要： A luminescence analytical method for the quantification of neonicotinoid pesticides (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam) in water samples is proposed. The method is based on the quenching effect that these analytes produce on the time-resolved luminescence signal of terbium ions (excitation/emission wavelengths of 256/545 nm/nm). An enhancement on the analytical signal is observed when surfactants are used in the system. The use of a 0.01 mol·L?1 sodium dodecyl sulfate produced approximately a 30% increase in the sensitivity of the method. Under the optimum conditions, the method presented detection limits between 0.03 and 0.23 μg·mL?1. Interference studies were performed for ions commonly present in waters, observing no interferences. In addition, recovery experiments were performed in different waters, well, spring, and swamp, observing recovery yields close to 100%, with relative standard deviations lower than 4% in all cases. No sample treatment except a filtration step was required. Hence, this method may represent an alternative to other existing methods for the quick and simple analysis of these ubiquitous insecticides in environmental waters.
关键词： neonicotinoid pesticides,surfactants,time-resolved luminescence,terbium luminescence,water samples
更新于2025-09-04 15:30:14
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Construction of a Layered Hydrogen-Bonded Organic Framework Showing High-Contrast Mechanoresponsive Luminescence Turn-On
摘要： This paper probes the mechanoresponsive luminescence and aggregation-induced emission (AIE) properties of N-phenylcarbazole-based thiophene/dicyanovinyl (T?DCV) derivatives. In bis-T?DCV planar molecule 1, a layered hydrogen-bonded organic framework (HOF) structure is formed with the assistance of multiple C?H···N and strong interlayer interactions. The formation of such a layer packing HOF structure can quench the solid fluorescent emission when aggregated as nanosuspensions but guarantees the high-contrast luminescence on?off switching (1.2 × 103 fold) in the solid state. Moreover, the grinding-induced destruction of HOF 1 is reflected by powder X-ray diffraction measurements, in which the destruction of the α and β rings in the planar HOF stripe and the close interlayer stacking could be observed. This work achieves the successful construction of long-wavelength emission AIE molecules (2 and 3) by introducing sufficient steric hindrance rotors to disturb the intermolecular π?π stacking and/or dipole?dipole interactions.
关键词： high-contrast luminescence,aggregation-induced emission,mechanoresponsive luminescence,hydrogen-bonded organic framework,thiophene/dicyanovinyl derivatives
更新于2025-09-04 15:30:14
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Upconversion luminescence modification induced near infrared luminescence enhancement of Bi2Ti2O7:Yb3+, Er3+ inverse opals
摘要： To date, there are comprehensive researches on rare-earth doped photonic band gap (PBG) materials. The PBG materials can effectively modify the up-conversion luminescence (UCL) of rare earth ions. However, few people pay attention to the influence of modification of the UCL of rare earth ions on their near infrared (NIR) luminescence. In this article, the Bi2Ti2O7: Yb3+, Er3+ inverse opal PBG materials were prepared, and the influence of modification of the UCL of Er3+ on their NIR luminescence was investigated systematically by changing the PBG position. The green and red UCL were suppressed when the PBG was overlapped the UCL of Er3+. The UCL modification induced NIR luminescence enhancement was observed in the Bi2Ti2O7: Yb3+, Er3+ inverse opal, which was attributed to the energy redistribution caused by the PBG effect. The suppression of UCL results in that the electrons located at the UCL levels relax to the NIR luminescence level of 4I13/2, causing the NIR luminescence enhancement. Our research can provide a promising method for the enhancement of the NIR luminescence.
关键词： Enhancement,Inverse opal,up-conversion luminescence,Near infrared luminescence
更新于2025-09-04 15:30:14
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Enhancement of Red Upconversion Emission of LiGdF <sub/>4</sub> :Yb <sup>3+</sup> /Ho <sup>3+</sup> Nanorods by Doping with Ce <sup>3+</sup>
摘要： A series of tetragonal phase LiGdF4:Yb3+/Ho3+ nanorods tri-doped with Ce3+ have been successfully prepared via a facile oil heated method at 200 °C. The visible green and red upconversion emissions have been achieved and the red emission intensity is enhanced gradually with increasing Ce3+ concentration. The ratio of red to green emission of the Ho3+ ions is boosted about 20-fold due to efficient cross relaxation processes between Ho3+ and Ce3+ ions, which promote the red emission and weaken the green emission. The crystal phase and morphology of the nanorod samples were inspected by X-ray diffraction and transmission electron microscopy, respectively. This work has great potential applications in the biological imaging, biomedical and color display applications.
关键词： Energy Transfer,Upconversion Luminescence,Nanorods LiGdF4
更新于2025-09-04 15:30:14
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Synthesis and Spectroscopic Properties of Cationic Bis(bipyridine)-Phosphine Ruthenium Complexes
摘要： The syntheses of heteroleptic bis-bipyridine ruthenium(II) complexes [Ru(R-bpy)(R'-bpy)(PPh3)Cl][PF6] {(2) R-bpy = R'-bpy = 4,4'-dimethyl-2,2'-bipyridine and (3) R-bpy = 4,4'-dimethyl-2,2'-bipyridine, R'-bpy = 4,4'-dimethoxy-2,2'-bipyridine} were achieved by addition of ammonium hexafluorophosphate to a solution of equimolar amounts of trans, cis-[Ru(Me-bpy)(PPh3)2Cl2] and R'-bpy on refluxing chloroform. The new complexes were characterized by NMR (31P, 1H), IR spectroscopy, mass spectrometry and elemental analysis. The structure of [Ru(Me-bpy)(MeO-bpy)(PPh3)Cl][PF6] was identified by X-ray crystallography. Electronic absorption and emission spectra of the complexes were collected. Weak emissions in both complexes were highlighted at room temperature in the range 618-625 nm in methanol and acetonitrile. No emission were observed in chloroform solutions, suggesting that the rate of non-radiative decay (energy transfer) of the singlet metal-to-ligand charge transfer (1MLCT) excited state is approaching or even faster than that of the inter-system crossing.
关键词： Heteroleptic,Bis(bipyridine),Ruthenium,Luminescence
更新于2025-09-04 15:30:14