Multifunctional Ba(10-x) Nix La30 Si60 Glassy Composites for Thermoluminescent, and Opto-electronic Use

Past three decades to current literature, lanthanum silicates embedded with nickel ions are notable for different opto-electronic and semiconducting use. Current days of opto-electronics, including advanced semiconducting resources, need different assemblies of glass resources employing elastic, luminescent, and electronic characteristics. In this view, the opto-electronic resource of chemical composition Ba(10-x)NixLa30Si60 has planned for synthesis followed by mechanical, thermoluminescent, and opto-electronic characterization. The materials developed are showing glassy behavior, and which was confirmed by the structural characterization. The glass with 0.6 mol% NiO concentration exhibiting better thermal stability. Observations made on the elastic characterization of glasses suggested covalent structure. DTA results which include thermal stabilities of glasses, suggest materials are capable of high thermal stability. Molecular structure of glasses studied with the help of FT-IR spectra. Different structural units and their waves number positions are identified and analysed. Which also suggested glassy behavior. D.C. Conductivity reports suggest that the materials are electrically active, and they are showing few orders of ionic conductivity. A decrease in optical basicity with increasing NiO mol% of glasses suggests high order of covalence. Trap depth parameters (Tm, E𝛕, E𝛅, E𝛚 & ms) under thermoluminescence studies suggest glass with 0.6 mol% NiO concentration is a beneficial TL resource. Optical absorption spectra of glasses is recorded, and which helps to calculate the Racah parameters of glasses. Refractive index, emissive cross-section, optical band gap, and transition probability of nickel hosted present glasses evaluated with the help of photoluminescence characterization. This suggests glasses embedded with nickel ions are highly photonic. All the outcomes from the various characterization of glasses which include mechanical, thermoluminescent, and photo-electronic results, suggest a glass with 0.6 mol% NiO concentration is a helpful thermoelement and opto-electronic resource.

Multiple Optical Features In Binary-Transition-Metal Borate Glasses

Glasses doped with transition metal (TM) ions exhibit rich optical transitions spanning the entire ultraviolet, visible, and infrared spectral regimes. Here we utilize the melt-quenching techniques to synthesis binary-TM-doped borate glasses of composition xCuO-(75-x)B2O3-24.7Li2O-0.3Cr2O3, with x = 0, 0.2, 1.0 and 2.0 mol %. We identify several optical transitions from Cr3+, Cr6+, and Cu2+ ions, the latter manifests at longer wavelengths and gains higher intensity with Cu additives. Despite Cr concentration being fixed, the Cr6+ peaks are quenched and Cr3+ signals are barely attenuated. This behavior rules out possible phase separation and suggests non-trivial interplay between the two TM ions and ligand, as supported by probing their oxidation states from electron spin resonance. The crystal field and Racah parameters followed an opposite behavior, while the optical band gap is reduced upon doping. These changes are correlated with structural modifications introduced by Cu additives, where we anticipate homogenous and preferential proximity of Cu-Cr ions within the network.

Deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics for plant lighting

In this study, deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the demanded wavelength for photosynthesis. The crystal field strength (Dq) and the Racah parameters (B and C) were estimated by the Tanabe-Sugano diagram. The thermal conductivity of the Mg2Ti(0.999)O4:0.001Mn4+ ceramic was 7.535 W/(m·K) at room temperature, which was one order of magnitude higher than that of the traditional packaging method using the silicone gel. A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue region to the purple light region with the thickness of the ceramic increasing. These results indicated that the Mg2TiO4:Mn4+ phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.

Deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics for plant lighting

In this study, deep red emitting Mg2TiO4:Mn4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the demanded wavelength for photosynthesis. The crystal field strength (Dq) and the Racah parameters (B and C) were estimated by Tanabe-Sugano diagram. The thermal conductivity of the Mg2Ti(0.999)O4: 0.001Mn4+ ceramic was 7.535 W/(m·K) at room temperature, which was one order of magnitude higher than that of the traditional packaging method using the silicone gel. A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue region to the purple light region with the thickness of the ceramic increasing. These results indicated that the Mg2TiO4:Mn4+ phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.

Deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics for plant lighting

In this study, deep red emitting Mg2TiO4:Mn4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the most efficient wavelength for photosynthesis. The crystal field strength (Dq) and the Racah parameters (B and C) are estimated by Tanabe-Sugano diagram. The thermal conductivity of the ceramics was 7.535 W/(m·K) at room temperature, which was one order of magnitude higher than that of the traditional packaging method using silicone gel. A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue light region to the purple light region with the thickness of the ceramic increasing. These results indicated that the Mg2TiO4:Mn4+ phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.

The Tyranny of Arm-Wrestling Methyls on Iron(II) Spin State in Pseudo-Octahedral [Fe(didentate)3] Complexes

The connection of a sterically constrained 3-methyl-pyrazine ring to a N-methyl-benzimidazole unit to give the unsymmetrical α,α’-diimine ligand L5 has been programmed for the design of pseudo-octahedral spin-crossover [Fe(L5)3]2+ units, the transition temperature (T1/2) of which occurs in between those reported for related facial tris-didentate iron chromophores fitted with 3-methyl-pyridine-benzimidazole in a LaFe helicate (T1/2 ~ 50 K) and with 5-methyl-pyrazine-benzimidazole L2 ligands (T1/2 ~350 K). A thorough crystallographic analysis of [Fe(L5)3](ClO4)2 (I), [Ni(L5)3](ClO4)2 (II), [Ni(L5)3](BF4)2∙H2O (III), [Zn(L5)3](ClO4)2 (IV), [Ni(L5)3](BF4)2∙1.75CH3CN (V), and [Zn(L5)3](BF4)2∙1.5CH3CN (VI) shows the selective formation of pure facial [M(L5)3]2+ cations in the solvated crystals of the tetrafluoroborate salts and alternative meridional isomers in the perchlorate salts. Except for a slightly larger intra-strand interannular twist between the aromatic heterocycles in L5, the metric parameters measured in [Zn(L5)3]2+ are comparable to those reported for [Zn(L2)3]2+, where L2 is the related unconstrained ligand. This similitude is reinforced by comparable ligand-field strengths (∆oct) and nephelauxetic effects (as measured by the Racah parameters B and C) extracted from the electronic absorption spectra recorded for [Ni(L5)3]2+ and [Ni(L2)3]2+. In this context, the strictly high-spin behavior observed for [Fe(L5)3]2+ within the 5–300 K range contrasts with the close to room-temperature spin-crossover behavior of [Fe(L2)3]2+ (T1/2 = 349(5) K in acetonitrile). This can be unambiguously assigned to an intraligand arm wrestling match operating in bound L5, which prevents the contraction of the coordination sphere required for accommodating low-spin FeII. Since the analogous 3-methyl-pyridine ring in [Fe(L3)3]2+ derivatives are sometimes compatible with spin-crossover properties, the consequences of repulsive intra-strand methyl–methyl interactions are found to be amplified in [Fe(L5)3]2+ because of the much lower basicity of the 3-methyl-pyrazine ring and the resulting weaker thermodynamic compensation. The decrease of the stability constants by five orders of magnitude observed in going from [M(L2)3]2+ to [M(L5)3]2+ (M = NiII and ZnII) is diagnostic for the operation of this effect, which had been not foreseen by the authors.

Spectroscopic Properties, Magnetic Behaviours and Hirshfeld Surface Analysis of Ag[Cr(1,3-pdta)]·3H2O

The presence of various functional groups present in Ag[Cr(1,3-pdta)]·3H2O (1,3-pdta = 1,3-propanediaminetetraacetate) was confirmed by FT-IR spectral results. The electronic spectral properties and magnetic behaviours were also described. The results of our calculations yielded the crystal field splitting and Racah parameters of Dq = 1969 cm-1, B = 594 cm-1 and C = 3250 cm-1. Hirshfeld surface analysis by three-dimensional (3D) molecular surface contours and two-dimensional (2D) fingerprint plots were performed to visualize, explore and quantify the intermolecular interactions in the crystal lattice. Hirshfeld surface contours and 2D fingerprint maps revealed that the crystal packing is dominated by H···O/O···H and H···H contacts. The strong hydrogen-bonding interactions are linked with O–H···O consisting the highest fraction of 63.4% followed by these of the H···H type contributing 25.5%. Other very weak contacts of Ag···O/O···Ag, C···H/H···C, O···O, Ag···H/H···Ag and O···C/C···O are present in the title compound.