Organic Chromophores-Based Sensitization of NIR-Emitting Lanthanides

Hernández, Ignacio Colomer; Gillin, W. P.

doi:10.1016/b978-0-444-63481-8.00269-4

Cited by 16 publications

(14 citation statements)

References 216 publications

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“…If this is relatively simple to achieve in purely inorganic compounds, it is more problematic with coordination compounds having organic ligands; not only the often cited O–H and N–H vibrations are efficient quenchers, but also C–H, C=O, and C=C vibrations contribute substantially. To minimize the corresponding quenching, one usual trick is to deuterate the ligands or, better, to fluorinate them . Another strategy is to use a perfluorinated environment for the emissive ion linked to an efficient, nonfluorinated sensitizer lying outside the inner coordination sphere, as tested for Er III .…”

Section: Highly Luminescent Chelates and Compoundsmentioning

confidence: 99%

Rising Stars in Science and Technology: Luminescent Lanthanide Materials

Bünzli

2017

Eur J Inorg Chem

175

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This essay draws attention to lanthanide luminescence by putting into perspective the sensitization process of f-f emission, the design of highly luminescent lanthanide-based compounds, and upconversion nanoparticles. A brief overviewLanthanide luminescence is at the heart of applications as diverse as lighting, telecommunications, displays, lasers, security inks and marking, pressure sensors, barcoding, molecular thermometers, immunoassays, and bioimaging ( Figure 1). The phenomenon is fascinating and has constantly accompanied the development of lanthanide science and technology, from the early discovery of the 4f elements to the present high-technology applications. Lanthanide-containing light-emitting materials (phosphors and pigments) represent the second most important application of rare earths with respect to the commercial value of the oxides needed for their production, just behind magnets. However, tonnage-wise these materials represent a rather small share of the total rare earths used annually, about 4 %. In addition to the fascination for light emission, this large added value explains the enthusiasm research groups have in looking for new and better luminescent materials.Most lanthanide ions are luminescent, and the corresponding transitions occur either as allowed d-f transitions or as electronic rearrangements within the 4f shell (f-f transitions). Interconfigurational d-f transitions are more energetic and more intense than f-f transitions but are observed in the common UV/visible spectroscopic range only for Ce III , Pr III , Tb III , and some Ln II ions (Ln = Sm, Eu, Tm, Yb). Electric-dipole (ed) f-f transitions are forbidden by Laporte's selection rule, while magnetic-dipole [a]

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Section: Highly Luminescent Chelates and Compoundsmentioning

confidence: 99%

Rising Stars in Science and Technology: Luminescent Lanthanide Materials

Bünzli

2017

Eur J Inorg Chem

175

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“…For the Yb complex 8 , the exponent function is not fitted well and the lifetime varies in the range 5–7 μs (Figure S5). The lifetimes of the NIR PL of the obtained complexes are essentially shorter than those of compounds of respective lanthanides with other perfluorinated ligands (30–700 μs) [49,50]. Apparently, this behavior is due to the presence of strong quenchers (coordinated DME molecules) in these complexes.…”

Section: Resultsmentioning

confidence: 87%

Features of the Molecular Structure and Luminescence of Rare-Earth Metal Complexes with Perfluorinated (Benzothiazolyl)phenolate Ligands

et al. 2019

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A set of Sc, Nd, Sm, Eu, Ho, Gd, Er, Yb complexes with perfluorinated 2-(benzothiazol-2-yl)phenolate ligands Ln(SONF)3(DME) were synthesized by the reactions of silylamides Ln[N(SiMe3)2]3 with phenol H(SONF). The structure of the initial phenol, Sc, and Er complexes was established using X-ray analysis, which revealed that the obtained compounds are mononuclear, in contrast to the binuclear non-fluorinated analogues [Ln(SON)3]2 synthesized earlier. All the obtained complexes, both in solid state and in tetrahydrofuran (THF) solutions, upon excitation by light with λex 395 or 405 nm show intense luminance of the ligands at 440–470 nm. The Eu complex also exhibits weak metal-centered emission in the visible region, while the derivatives of Sm luminesces both in the visible and in the infrared region, and Nd, Er, and Yb complexes emit in the near IR (NIR) region of high intensity. DFT (density functional theory) calculation revealed that energy of frontier orbitals of the fluorinated complexes is lower than that of the non-fluorinated counterparts. The level of highest occupied molecular orbital (HOMO) decreases to a greater extent than the lowest occupied molecular orbital (LUMO) level.

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“…30 Nevertheless, potential applications in telecommunications 34,99 of the Er 3+ 4 I13/2→ 4 I15/2 transition with an emission wavelength at ~1500 nm have initiated multiple attempts to create and enhance Er 3+ emission in coordination compounds. [100][101][102] The observation of Er 3+ transitions in the visible range is uncommon and only a few examples could be found in the literature. 56,58,[103][104] Nevertheless, we could unambiguously detect 2 H11/2→ 4 I15/2 and 4 S3/2→ 4 I15/2 transitions between 520 and 565 nm and as multiple bands in the range of 1450-1650 nm due to the 4 I13/2→ 4 I15/2 transition in the emission spectrum of Er-1 in the solid state (Figure 2).…”

Section: Photophysical Propertiesmentioning

confidence: 99%

Visible, Near-Infrared, and Dual-Range Luminescence Spanning the 4f Series Sensitized by a Gallium(III)/Lanthanide(III) Metallacrown Structure

et al. 2020

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Lanthanide(III) ions (Ln 3+ ) in coordination compounds exhibit unique luminescent properties with narrow and characteristic f-f transitions throughout the visible and near-infrared (NIR) ranges. In addition, some Ln 3+ such as Pr 3+ , Sm 3+ , Dy 3+ , Ho 3+ , Er 3+ and Tm 3+ possess an exceptional ability, although less explored, to exhibit dual-range emissions. Such remarkable features allow highly specific use in materials sciences and biology, for example, for the creation of sophisticated barcode modules or for the next generation of optical imaging applications. Herein, a series of Ga 3+ /Ln 3+ metallacrowns (MCs) with the general composition [LnGa8(shi)8(OH)4]Na•xCH3OH•yH2O (Ln-1, Ln = Pr 3+ , Nd 3+ , Sm 3+ -Yb 3+ and analogue Y 3+ ; H3shi = salicylhydroxamic acid) is presented. Ln-1 were obtained by reacting Ga 3+ and Ln 3+ nitrate salts with the H3shi ligand. X-ray single crystal unit cell analysis confirmed that all MCs are isostructural. The crystal structure was solved for the Nd 3+ analogue and revealed that Nd 3+ is centered between two [12-MCGa III N(shi)-4] MC rings and bound to eight hydroximate oxygen ions (four from each ring) in a pseudo-square antiprismatic fashion adopting a pseudo-D4h symmetry. PGSE DOSY 1 H NMR spectroscopy and ESI mass-spectrometry confirmed that the structure of Ln-1 remains intact in methanol solutions while mass spectrometry suggests that four OHbridges are exchanged with CH3O -/CD3O -. An exceptional ability of this series of MCs to sensitize the characteristic emission of Ln 3+ was confirmed with the observation of bright red and green emission signals of Eu-1 and Tb-1, NIR emissions of Yb-1 and Nd-1, and dual-range emissions of Pr-1, Sm-1, Dy-1, Ho-1, Er-1 and Tm-1 in the solid state upon excitation into ligand-centered bands at 340 nm. The luminescence properties of Ln-1 (Ln = Nd 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Yb 3+ ) were also investigated in CH3OH and CD3OD solutions. For Eu-1 and Yb-1 MCs, more extensive analyses of the photophysical properties were performed that included the determination of radiative lifetimes, intrinsic quantum yields and sensitization efficiencies. The absolute quantum yields ( ) of Ln-1 in the visible and in the NIR ranges have been determined. In the case of Sm-1 the values of in CH3OH and CD3OD solutions are exceptionally high, i.e. 10.1(5) % and 83(1) %. Values obtained for Yb-1, i.e. 0.78(4) % in CH3OH and 8.4(1)% in CD3OD, are among the highest ones reported today for Yb 3+ complexes formed with non-deuterated and non-halogenated ligands.Absorption spectra. Absorption spectra (Figure S9) were collected on freshly prepared 50 µM solutions of Ln-1 in methanol (Merck, Uvasol®) placed in quartz cuvettes on a Jasco V670 UV-visible spectrophotometer in absorbance mode.Synthesis and characterization. All reagents and chemicals were purchased from commercial sources and used without further purification. All reactions were carried out aerobically under ambient conditions. Elemental analysis was performed by Atlantic Microlabs Inc. ESI-M...

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Organic Chromophores-Based Sensitization of NIR-Emitting Lanthanides

Cited by 16 publications

References 216 publications

Rising Stars in Science and Technology: Luminescent Lanthanide Materials

Rising Stars in Science and Technology: Luminescent Lanthanide Materials

Features of the Molecular Structure and Luminescence of Rare-Earth Metal Complexes with Perfluorinated (Benzothiazolyl)phenolate Ligands

Visible, Near-Infrared, and Dual-Range Luminescence Spanning the 4f Series Sensitized by a Gallium(III)/Lanthanide(III) Metallacrown Structure

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