Luminescence Properties of M(AlCl):Yb (M = Ca, Sr, Ba): Ideal Materials for the Investigation of Structure-Luminescence Relationships.

In this work, the chloride system M(AlCl) (M = Ca, Sr, Ba) doped with Yb is investigated in greater detail. The influence of the [AlCl] ion on the position of the emission band of Yb is investigated and the emission spectra are recorded. The emission spectra of the Yb-doped materials are characterized by broad 4f5d (HS) ↔ 4f transitions with maxima in the range between 416 nm (Ca) and 421 nm (Ba) (24,061-23,738 cm), whereas the Ba compound features an additional 4f5d (LS) ↔ 4f emission band at 397 nm (25,203 cm) at lower temperatures.

The Divalent Lanthanoid Triflates Ln(CFSO)(CHCN) (Ln=Sm, Eu): Structure, Luminescence, and Magnetism.

The reaction of the trivalent lanthanoide triflates Ln(OTf) (Ln=Sm, Eu; OTf=CFSO ) with the respective metals in acetonitrile leads to the Ln(II)-triflates Eu(OTf)(CHCN) (monoclinic, P2/n, Z=4, a=1053.54(1), b=610.28(5), c=1946.

Impact of 1,10-Phenanthroline-Induced Intermediate Valence on the Luminesence of Divalent Europium Halides.

Starting from EuX (X = Cl, Br, I), we systematically investigated a variety of divalent europium complexes containing bidentate 1,10-phenanthroline (Phen) ligands. Depending on the Eu/Phen ratio, mono-, di-, and polynuclear complexes are formed, with the latter yielding one-dimensional [EuBr(phen)] chains. Seven new divalent europium complexes, [Eu(phen)(HO)]Br·2MeCN, [Eu(phen)]I·1.

Thermally and Optically Activated Migration of Charge Carriers in Alkali Metal Sesquioxides.

The alkali metal sesquioxides A O (A=K, Rb, Cs) are mixed-valent with respect to oxygen and display several degrees of electronic and structural freedom, which give rise to diverse transport and ordering processes. We report on analyses of the respective underlying excitations by diffuse reflectance spectroscopy and thermally activated electron transport. Backed by DFT based band structure calculations we identify three possible mechanisms, inter valence charge transfer from peroxide to superoxide, excitation across the Jahn-Teller gap of tilted superoxide anions, and polaron migration.

Development of Gold Nanoparticle-Based SERS Substrates on TiO-Coating to Reduce the Coffee Ring Effect.

Hydrophilic surface-enhanced Raman spectroscopy (SERS) substrates were prepared by a combination of TiO-coatings of aluminium plates through a direct titanium tetraisopropoxide (TTIP) coating and drop coated by synthesised gold nanoparticles (AuNPs). Differences between the wettability of the untreated substrates, the slowly dried Ti(OH) substrates and calcinated as well as plasma treated TiO substrates were analysed by water contact angle (WCA) measurements. The hydrophilic behaviour of the developed substrates helped to improve the distribution of the AuNPs, which reflects in overall higher lateral SERS enhancement.

Magnetism and Afterglow United: Synthesis of Novel Double Core-Shell Eu -Doped Bifunctional Nanoparticles.

Afterglow-magnetic nanoparticles (NPs) offer enormous potential for bioimaging applications, as they can be manipulated by a magnetic field, as well as emitting light after irradiation with an excitation source, thus distinguishing themselves from fluorescent living cells. In this work, a novel double core-shell strategy is presented, uniting co-precipitation with combustion synthesis routes to combine an Fe O magnetic core (≈15 nm) with an afterglow SrAl O :Eu ,Dy outer coat (≈10 nm), and applying a SiO protective middle layer (≈16 nm) to reduce the luminescence quenching caused by the Fe core ions. The resulting Fe O @SiO @SrAl O :Eu ,Dy NPs emit green light attributed to the 4f 5d →4f ( S ) transition of Eu under UV radiation and for a few seconds afterwards.

Eu(O C-C≡C-CO ): An Eu Containing Anhydrous Coordination Polymer with High Stability and Negative Thermal Expansion.

Anhydrous Eu -acetylenedicarboxylate (EuADC; ADC = O C-C≡C-CO ) was synthesized by reaction of EuBr with K ADC or H ADC in degassed water under oxygen-free conditions. EuADC crystallizes in the SrADC type structure (I4 /amd, Z=4) forming a 3D coordination polymer with a diamond-like arrangement of Eu nodes (msw topology including the connecting ADC linkers). Deep orange coloured EuADC is stable in air and starts decomposing upon heating in an argon atmosphere only at 440 °C.

A Guide to Brighter Phosphors-Linking Luminescence Properties to Doping Homogeneity Probed by NMR.

Crystalline powders of Ln doped LaPO (Ln=Nd, Gd, Dy, Ho, Er, Tm, Yb) have been synthesized to serve in a case study for linking doping homogeneity as determined by NMR to luminescent properties. Samples obtained via different synthesis methods act as examples of homo- and inhomogeneous doping. The sample quality was verified by X-ray diffraction.

Detection of spoilage associated bacteria using Raman-microspectroscopy combined with multivariate statistical analysis.

Raman-Microspectroscopy with subsequent chemometric evaluation was used for the rapid and non-destructive differentiation of seven important spoilage related microorganisms, namely Brochothrix thermosphacta DSM 20171, Pseudomonas fluorescens DSM 4358, Pseudomonas fluorescens DSM 50090, Micrococcus luteus, Escherichia coli HB101, Escherichia coli TOP10 and Bacillus thuringiensis israelensis DSM 5724. Therefore fast collected spectra directly from rapid surface blots without any pretreatments like purification or singulation steps were used. To estimate and classify the Raman-spectroscopic data at genera and strain level an adequate preprocessing together with a subsequent chemometric evaluation consisting of principal component analysis and discriminant analysis was used.

Facile Ionic Liquid-Assisted Strategy for Direct Precipitation of Eu -Activated Nanophosphors under Ambient Conditions.

This work describes a novel ionic liquid (IL)-assisted synthesis strategy for a direct and easy production of Eu -doped nanoparticles (NPs), where ILs are also used as fluoride sources to avoid the use of elemental fluorine or toxic hydrofluoric acid. Up to now, the direct synthesis of Eu -doped nanophosphors consisted of an enormous challenge, due to the oxidation to Eu observed in hydrous solution, which is commonly used for the preparation of NPs, generating lattice defects and undesired particle growth or agglomeration by additional reducing steps at high temperatures. In contrast, ILs, unless containing ClO or NO anions, do not present an oxidizing character, allowing the direct precipitation of NPs, e.

Bright Photoluminescence of [{(CptBu2 ) Ce(μ-Cl)} ]: A Valuable Technique for the Determination of the Oxidation State of Cerium.

The synthesis and photoluminescence properties of the bright-yellow organocerium complex [{(CptBu2 ) Ce(μ-Cl)} ] (CptBu2 =1,3-di(tert-butyl)cyclopentadienyl) are presented. This coordination compound exhibits highly efficient photoluminescence within the yellow-light wavelength range, with a high internal quantum yield of 61(±2) % at room temperature. The large red shift is attributed to the delocalizing ability of the aromatic ligands, whilst its quantum yield even makes this compound competitive with Ce -activated LED phosphors in terms of its photoluminescence efficiency (disregarding its thermal stability).

Oscillating Emission of [2]Rotaxane Driven by Chemical Fuel.

A molecular shuttle consisting of a dibenzo-24-crown-8 macrocycle and an axle with two degenerate peripheral triazolium stations, a central dibenzyl ammonium station, and two anthracenes stoppers was exposed to 2-cyano-2-phenylpropanoic acid as a chemical fuel. Protonation/deprotonation of the amine reversibly switches the rotaxane from a static and little emissive to a dynamic fluorescent shuttling device, the latter exhibiting rapid motion (15 kHz at 25 °C). Four fuel cycles were run.

Green Synthesis of A SiF (A=Li-Cs) Nanoparticles using Ionic Liquids as Solvents and as Fluorine Sources: A Simple Approach without HF.

In this Communication, nanoparticles of the fluoridosilicates A SiF (A=Li, Na, K, Rb, Cs), which are extremely promising host lattices for future LEDs, are presented for the first time. The preparation method we introduce here is a very simple and energy and time saving one, moreover the usage of toxic HF or elemental fluorine is avoided. In detail, the ionic liquid [Bmim]PF was used both as solvent and fluoride source in an ionothermally assisted microwave synthesis.

Decay times of the spin-forbidden and spin-enabled transitions of Yb doped in CsCaX and CsSrX (X = Cl, Br, I).

In this paper, a systematic study of the decay times of the spin-enabled and spin-forbidden transitions of Yb doped into the halidoperovskites CsMX (M = Ca, Sr; X = Cl, Br, I) is presented. The spin-forbidden transitions are characterized by ms decay times, which are typical for Yb. On the contrary, the spin-enabled transitions show much shorter decay times in the range of μs and have so far only been rarely observed.

ABiO2X (A = Cd, Ca, Sr, Ba, Pb; X = halogen) Sillen X1 Series: Polymorphism Versus Optical Properties.

The Sillen X1 series of Bi(3+)A(2+)O2X (A = Cd, Ca, Sr, Ba, Pb; X = Cl, Br, I) compounds is composed of three main crystallographic types, namely, the tetragonal form (space group (S.G.) I4/mmm), the orthorhombic form (S.

Photoluminescence properties of Yb(2+) ions doped in the perovskites CsCaX3 and CsSrX3 (X = Cl, Br, and I) - a comparative study.

The Yb(2+)-doped perovskite derivatives CsMX3 (M = Ca and Sr; X = Cl, Br, and I) are ideal systems for obtaining a detailed insight into the structure-luminescence relationship of divalent lanthanides. The investigation of the respective photoluminescence properties yielded two emission bands in the violet and blue spectral range for all compounds, which are assigned to the spin-allowed and spin-forbidden 5d-4f transitions, respectively. The impact on their energetic positions is dependent on both the covalency of the Yb(2+)-halide bond and the corresponding bond length in agreement with expectations.

Prospecting Lighting Applications with Ligand Field Tools and Density Functional Theory: A First-Principles Account of the 4f(7)-4f(6)5d(1) Luminescence of CsMgBr3:Eu(2+).

The most efficient way to provide domestic lighting nowadays is by light-emitting diodes (LEDs) technology combined with phosphors shifting the blue and UV emission toward a desirable sunlight spectrum. A route in the quest for warm-white light goes toward the discovery and tuning of the lanthanide-based phosphors, a difficult task, in experimental and technical respects. A proper theoretical approach, which is also complicated at the conceptual level and in computing efforts, is however a profitable complement, offering valuable structure-property rationale as a guideline in the search of the best materials.

The synthesis of the heterocubane cluster [{CpMn}4(μ3-P)4] as a tetrahedral shaped starting material for the formation of polymeric coordination compounds.

Thermolysis of [CpMn(η(6)-cht)] with P4 in 1,3-diisopropylbenzene leads to the formation of the heterocubane [Cp4Mn4P4] () in high yields, as a rare example of 'naked' phosphorus containing complexes of manganese. Compound is characterized and studied by DFT calculations and reflection measurements. 1D coordination polymers [{(CpMn)4(μ3-P)4}(CuX)]n (2-Cl: X = Cl; 2-Br: X = Br) are obtained in the reaction with CuX.

A Highly Triflated Rare-Earth Ion in [Eu(O3SCF3)8](5-).

The reaction of Eu2O3 with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch-sealed glass ampoules at 120 °C gave the europium compound (NO)5[Eu(O3SCF3)8] (orthorhombic, Fddd, Z = 16, a = 1932.69(4), b = 2878.44(7), c = 2955.

Heterometallic europium disiloxanediolates: synthesis, structural diversity, and photoluminescence properties.

This contribution presents a full account of a structurally diverse class of heterometallic europium disiloxanediolates. The synthetic protocol involves in situ metalation of (HO)SiPh2OSiPh2(OH) (1) with either (n)BuLi or KN(SiMe3)2 followed by treatment with EuCl3 in suitable solvents such as 1,2-dimethoxyethane (DME) or tetrahydrofuran (THF). Reaction of EuCl3 with 2 equiv of (LiO)SiPh2OSiPh2(OLi) in DME afforded the Eu(III) bis(disiloxanediolate) "ate" complex [{(Ph2SiO)2O}2{Li(DME)}3]EuCl2 (2), which upon attempted reduction with Zn gave the tris(disiloxanediolate) [{(Ph2SiO)2O}3{Li(DME)}3]Eu (3).