Bifunctional Luminescent Thermometer-Manometer Based on Cr-Cr Pair Emission.

Pressure dependence of spectral positions of the E → A and T → A bands of Cr ions, resulting from changes in Cr-O covalency and variations in crystal field strength, respectively, is commonly utilized in luminescence manometry. However, as demonstrated in this paper, the luminescence of Cr-Cr pairs shows insensitivity to pressure changes, making this signal suitable as a luminescence reference. The significant difference in the thermal and pressure dependences of luminescence with Cr occupying different crystallographic positions in CaAlO:Cr enables the development of a dual-function luminescence thermometer that operates in both ratiometric and lifetime-based readout modes.

2D Cu(I)-I Coordination Polymer with Smart Optoelectronic Properties and Photocatalytic Activity as a Versatile Multifunctional Material.

This work presents two isostructural Cu(I)-I 2-fluoropyrazine (Fpyz) luminescent and semiconducting 2D coordination polymers (CPs). Hydrothermal synthesis allows the growth of -1 space group single crystals, whereas solvent-free synthesis produces polycrystals. Via recrystallization in acetonitrile, 2 space group single crystals are obtained.

Stokes and upconverted luminescence in Er/Yb-doped YGaO nano-garnets.

The green, red, near-infrared and near-infrared-to-visible upconverted luminescence properties of Er3+/Yb3+ codoped Y3Ga5O12 nanocrystalline powders have been studied using laser spectroscopy. A diffuse reflectance and luminescence spectra confirm that Er3+ and Yb3+ ions occupy the Y3+ sites of the single-phase cubic nano-garnet. Very bright green and red luminescence of the Er3+ ions are detected by the naked eyes, even for a laser power as low as 15 mW, when the Yb3+ ions are excited at 970 nm.

Cu(I)-I-2,4-diaminopyrimidine Coordination Polymers with Optoelectronic Properties as a Proof of Concept for Solar Cells.

Two coordination polymers with formulas [CuI(dapym)] and [CuI(dapym)] (dapym = 2,4-diaminopyrimidine) have been synthesized in water at room temperature. According to the stoichiometry used, mono (1D) and the two-dimensional (2D) structures can be obtained. Both are made up of CuI double chains.

Structural and Lattice-Dynamical Properties of TbO under Compression: A Comparative Study with Rare Earth and Related Sesquioxides.

We report a joint experimental and theoretical investigation of the high pressure structural and vibrational properties of terbium sesquioxide (TbO). Powder X-ray diffraction and Raman scattering measurements show that cubic 3̅ (C-type) TbO undergoes two phase transitions up to 25 GPa. We observe a first irreversible reconstructive transition to the monoclinic 2/ (B-type) phase at ∼7 GPa and a subsequent reversible displacive transition from the monoclinic to the trigonal 3̅1 (A-type) phase at ∼1 GPa.

Smart composite films of nanometric thickness based on copper-iodine coordination polymers. Toward sensors.

One-pot reactions between CuI and methyl or methyl 2-amino-isonicotinate give rise to the formation of two coordination polymers (CPs) based on double zig-zag CuI chains. The presence of a NH group in the isonicotinate ligand produces different supramolecular interactions affecting the Cu-Cu distances and symmetry of the CuI chains. These structural variations significantly modulate their physical properties.

High pressure luminescence of Nd in YAlO perovskite nanocrystals: A crystal-field analysis.

Pressure-induced energy blue- and red-shifts of the F → I near-infrared emission lines of Nd ions in YAlO perovskite nano-particles have been measured from ambient conditions up to 29 GPa. Different positive and negative linear pressure coefficients have been calibrated for the emission lines and related to pressure-induced changes in the interactions between those Nd ions and their twelve oxygen ligands at the yttrium site. Potentiality of the simple overlap model, combined with ab initio structural calculations, in the description of the effects of these interactions on the energy levels and luminescence properties of the optically active Nd ion is emphasized.

Experimental and ab Initio Study of Catena(bis(μ2-iodo)-6-methylquinoline-copper(I)) under Pressure: Synthesis, Crystal Structure, Electronic, and Luminescence Properties.

Copper(I) iodine compounds can exhibit interesting mechanochromic and thermochromic luminescent properties with important technological applications. We report the synthesis and structure determination by X-ray diffraction of a new polymeric staircase copper(I) iodine compound catena(bis(μ2-iodo)-6-methylquinoline-copper(I), [C10H9CuIN]. The structure is composed of isolated polymeric staircase chains of copper-iodine coordinated to organic ligands through Cu-N bonds.

Stokes and anti-Stokes luminescence in Tm(3+)/Yb(3+)-doped Lu3Ga5O12 nano-garnets: a study of multipolar interactions and energy transfer dynamics.

Nanocrystalline Lu3Ga5O12 garnets doped with Tm(3+)/Yb(3+) ions have been synthesized by a low cost and environmentally benign sol-gel technique and characterized for their structural, Stokes and anti-Stokes luminescence properties. The diffuse reflectance spectra of doped Lu3Ga5O12 nano-garnets have been measured to derive the partial energy level structure of Tm(3+) and Yb(3+) ions and possible energy transfer channels between them. Upon laser excitation at 473 nm, weak red and intense near-infrared Stokes emissions have been observed in the nano-garnets.

Structural study of the Eu3+ environments in fluorozirconate glasses: role of the temperature-induced and the pressure-induced phase transition processes in the development of a rare earth's local structure model.

The correlation between the optical properties of the Eu(3+) ions and their local structures in fluorozirconate glasses and glass-ceramics have been analyzed by means of steady-state and time-resolved site-selective laser spectroscopies. Changes in the crystal-field interaction, ranging from weak to medium strength values, are observed monitoring the luminescence and the lifetime of the Eu(3+) ions in different local environments in the glass. As key roles in this study, the Eu(3+) luminescence in the thermally-induced crystallization of the glass and the pressure-induced amorphization of the crystalline phase of the glass-ceramic experimentally states the existence of a parent local structure for the Eu(3+) ions in the glass, identified as the EuZrF(7) crystalline phase.