A previously unexplored reaction of ReSe2 and WSe2 in a KCN melt resulted in the formation of the heterometallic cluster products, namely, the salt K5[Re5WSe8(CN)6] and the chain polymer K6[Re3.6W2.4Se8(CN)4(CN)2/2]. Oxidative depolymerization and the differences in redox behavior of the complexes enabled the isolation of soluble salts of the cluster anions [Re5WSe8(CN)6]4-, [Re4W2Se8(CN)6]4-, and [Re3W3Se8(CN)6]4- with TBA+ cations as individual crystalline compounds. A comparative study of the complexes shows that sequential substitution of rhenium atoms in the cluster core with electron-deficient tungsten atoms leads to periodic variations in the physicochemical properties of the clusters. This is reflected, for instance, in a cathodic shift of the redox potentials and in the greater number of accessible charge states. At the same time, DFT calculations indicate that the octahedral cluster geometry for electron-precise complexes is almost insensitive to the number of tungsten atoms and undergoes local distortions upon variation of the cluster skeletal electron count.

Rare-earth thiogermanates built from isolated {GeS4} tetrahedra are attractive as optical host lattices, yet rubidium members remain insufficiently explored. Here we report the synthesis of the new members of the RbLnGeS4 series (Ln = Ce, Pr, Nd, Sm, Gd) by a high-temperature reactive flux route and their comprehensive structural and spectroscopic characterization. All compounds crystallize in the non-centrosymmetric orthorhombic space group P212121 and feature anionic [LnGeS4]− layers separated by interlayer Rb+ cations. Single-crystal X-ray diffraction reveals a split Rb position at room temperature, whereas low-temperature data together with DSC measurements indicate suppression of the rubidium positional disorder upon cooling, consistent with a kinetically limited order–disorder process. Raman spectra are dominated by modes of isolated {GeS4} tetrahedra and show systematic Ln–S-related shifts across the series. Diffuse reflectance spectra of representative compounds RbLnGeS4 (Ln = Pr, Gd) yield optical band gaps of ≥3.3 eV. In addition, Sm3+-doped RbGdGeS4 exhibits red f–f emission consistent with a low-symmetry Sm3+ environment in this host lattice.

Optical functionality in luminous materials can be effectively tailored by manipulating the local symmetry environment of activator ions. To study the impacts of lattice engineering on photoluminescence and latent fingerprint detection, urea-assisted combustion was used to create Bi3⁺-doped Y₂O₃ phosphors co-doped with alkali metal ions (Li⁺, Na⁺, K⁺, Cs⁺). Prepared Y₂O₃ phosphors with co-doped with alkali metal ions has cubic phase with space group I –a 3 with dopant-induced lattice contraction and smaller crystallites. In FTIR study we observed vibrational bond due to Y-O stretching. Prepared phosphor has irregular particles size with average particle size ~140 nm. Bi3+ ions occupy C₂ and S₆ symmetry positions, according to optical investigations, resulting in separate 1S₀→3P₁ and 1S₀→1P₁ transitions. Alkali co-doping increased intensity without changing the spectrum, however emission changed from bluish-white (329–337 nm excitation) to blue (374 nm). Y₂O₃: Bi/Na demonstrated exceptional fingerprint visualization and nearly 100% color purity. These findings demonstrate that tunable luminescence for sophisticated photonic and forensic applications is made possible by Bi3⁺ site-symmetry modification via alkali lattice engineering.

This study thoroughly investigated the luminescence properties and inter-ionic energy interactions of Y2O3 phosphors doped with Bi3+-Eu3+-Er3+ ions, which were produced using a co-precipitation method. Structural analysis confirmed that the incorporated rare-earth ions were effectively integrated into the cubic Y2O3 framework, with no impurity phases observed. Studies of photoluminescence demonstrated that Bi3+ is crucial as a sensitizer when excited in the near-UV region, starting a sequential energy transfer from Bi3+ to Eu3+ and then to Er3+. Due to the wide absorption characteristic of Bi3+, effective excitation of Eu3+occurs, and some excited states of Eu3+ transfer to Er3+, resulting in a mixture of blue, red, and green emissions. It was discovered that modifying the concentration of Bi3+ had a considerable impact on the relative emission intensities, the degree of non-radiative pathways, and the overall colour output. Chromaticity calculations showed that the emission can be adjusted from being mainly blue at lower Bi3+ levels to more blended colors as Bi3+ loading rises. Overall, the results underscore that sensitization with Bi3+ provides a useful means of customizing the optical response of Y2O3 phosphors activated by various rare-earth ions.

In this study, a series of Y2O3:Eu phosphors with varying concentrations of europium (Eu) were synthesized using the solid-state reaction method. The prepared materials underwent comprehensive characterization through multiple techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and thermoluminescence (TL) analysis. The XRD data were subjected to Rietveld refinement to investigate phase formation and structural properties. The thermoluminescent properties of the synthesized phosphors were assessed by subjecting the samples to different excitation sources, namely gamma rays, carbon ion beams, and oxygen ion beams. The results indicated that the Y2O3:Eu phosphor exposed to gamma rays exhibited the highest TL emission intensity when the Eu concentration was at 0.5 mol

The utilization of luminescent phosphors in barcode technology can enhance the security feature. Using NaOH as a reducing agent, we have prepared Gd2O3:Eu3+/Er3+ for luminescent phosphor. The cubic structure of Gd2O3 phosphor is confirmed by the structural analysis conducted using XRD. Dopant Eu and Er induce lattice contraction and expansion in the host lattice, respectively. Based on SEM analysis, porous and irregular particles with an average size of 401 nm were observed. In Tem analysis of prepared phosphor have some particle are in spherical in shape. The formation of Gd2O3 was confirmed by Gd-O band stretching as shown in the FTIR analysis. The emission in the red and green regions is emitted by Gd2O3:Eu3+ and Gd2O3:Er3+, respectively. The emission peaks of Gd2O3:Eu3+/Er3+ are observed at 524 nm, 539 nm, 549 nm, 563 nm, 593 nm, 612 nm, and 629 nm when it is triggered by 363 nm, with a maximum energy transfer efficiency of 95.93%. Enhancing the security of barcodes can be achieved through the use of color-tunable Gd2O3:Eu3+/Er3+ phosphor. Gd2O3:Er3+ (1.5 mol%) is a prominent candidate for LED bulbs due to its CCT (5765 K).

The present work describes the luminescence properties of Bi3+ doped La2O3 phosphor. The effect of charge compensators Na+ and Cs+ has been studied in detail. The samples were prepared by wet-chemical synthesis route. The phase purity and morphology of the prepared phosphors were analyzed by XRD and SEM, respectively. The photoluminescence (PL) of Bi3+ doped La2O3 phosphor with co-doping of Na+ and Cs+ ions has been studied. The PL excitation spectrum of Bi3+ doped and Na+ and Cs+co-doped La2O3 phosphor showed broad excitation bands centered at 307 nm besides a small hump around 252 nm, these excitation bands are attributed to the 1S0 -> 1P1 and 1S0 -> 3P1 transitions of Bi3+ ions. Under excitation of 307 nm, PL emission spectrum was recorded for Bi3+ doped and Na+ and Cs+ co-doped La2O3 phosphors, where all the samples show similar nature of emission band. A broad emission band is recorded which is centered at 462 nm corresponding to 3P1 -> 1S0 transition. Charge compensator effect was studied and it was found that with the copping of Na+ and Cs+ ions, the emission intensity is enhanced drastically as compared to Bi3+ doped La2O3 phosphor. All the three samples were investigated by photometry, which revealed that the emission color falls in the blue region. The copping of Na+ and Cs+ ions increase the color purity of the samples. The overall findings suggested that proposed samples have superior luminescence properties and it's had potential for further investigations in luminescence material research for white light emitting diode (WLEDs) applications.

Pure La2O3 phosphors have been synthesized by environment friendly and cost-effective green synthesis method using orange juice. The prepared samples were analyzed by various characterization methods. The luminescence property of pure La2O3 samples with different concentrations of orange juice was analyzed by photoluminescence (PL) technique. The PL excitation spectrum of the prepared sample shows a broad excitation band centered at 371 nm. Under 371 nm excitation, the PL emission spectra show a broad emission band from 415 nm to 650 nm. The emission bands covered the blue, green and yellow color regions. The CIE chromaticity diagram shows the coordinate near the white color region. The experimental results show that the prepared La2O3 phosphors are very promising for future investigations in the field of lighting and display devices.

The photoluminescence properties of La2O3:Dy3+, La2O3:Sm3+, and La2O3:Dy3+, Sm3+ were investigated in the study. Phosphor is prepared by using solution combustion method by using to urea as fuel. XRD analysis confirms the formation of La2O3 with hexagonal crystal structure. Anomalous shifting in co-doped phosphor is studied. In SEM analysis, particle size of prepared sample is found in range of micrometer. The EDX study confirms the presence of Lanthanum and oxygen as key elements in the phosphor. In FT-IR, the La-O starching is observed. In PL Emission spectra of La2O3:Dy3+and La2O3: Sm3+ found in white and orange red region. Emission peak of La2O3:Dy3+, Sm3+phosphor at excitation wavelength 388 nm is found to 488 nm, 568 nm, 575 nm, 611 nm, and 654 nm. The energy transfer mechanism is studied between Dy and Sm. The outcome of this work is very useful for WLEDs application.

The substitution of cyanide ligands in heterometallic cluster complexes [Re3Mo3Q8(CN)6]5- and [Re4Mo2Q8(CN)6]n- (Q = S, n = 5; Q = Se, n = 4) with triphenylphosphine has been demonstrated for the first time. A one-step solvothermal synthesis in a DMF/H2O mixture with an excess of triphenylphosphine led to complete ligand substitution, resulting in the formation [Re3Mo3S8(PPh3)6], [Re4Mo2S8(PPh3)6]& sdot;1.5DMF, [Re3Mo3Se8(PPh3)6], and [Re4Mo2Se8(PPh3)6]. The crystal structures of compounds were determined by single crystal X-ray diffraction analysis. The optical properties of compounds were studied using diffuse reflectance spectroscopy, revealing that both the inner ligand type and metal core composition influence the optical bandgaps. The thermal behavior of compounds was investigated by TGA, revealing a two-stage decomposition process without degradation of the cluster cores and the loss of approximately four PPh3 ligands per formula unit.

It is known that niobium practically does not form cluster chalcogenide compounds of the {M-6(mu(3)-Q(8))} type, which are widespread in the chemistry of group 6 and 7 metals. This work reports the preparation of a series of polymeric and discrete niobium-containing heterometallic clusters based on the {Re5Nb(mu(3)-S-8)} and {Re5Nb(mu(3)-Se-8)} cores. The compounds were prepared by the high-temperature reaction between rhenium and niobium dichalcogenides in a KCN melt. The 1D polymers K-5[Re(5)NbQ(8)(CN)(5)] (Q = S or Se), which were formed as a result of the reaction, crystallize in the structural type of K-6[Mo6Se8(CN)(5)], similar to the previously reported heterometallic clusters K-6[Re(6-x)Mo(x)Q(8)(CN)(5)] (x = 2-3). The polymers were solubilized to form discrete anionic clusters [Re(5)NbQ(8)(CN)(6)](4-). The structure and properties of the new clusters were investigated using a combination of X-ray diffraction analysis, UV/vis spectroscopy, high-resolution electrospray mass spectrometry, cyclic voltammetry, and DFT calculations. Among other features, the compounds showed high electrochemical activity, being able to form three redox states in solution with reversible transitions. It was found that redox potentials of the isoelectronic octahedral clusters demonstrate a strong cathodic shift in the sequence [Re5OsSe8(CN)(6)](3-) > [Re6Se8(CN)(6)](4-) > [Re5MoSe8(CN)(6)](5-) > [Re5NbSe8(CN)(6)](6-), illustrating the effect of systematic changes in the composition of octahedral cluster cores on their properties.

Metal atom clusters are well-defined nanoscale objects containing a precise number of metal atoms and ligands. Face-capped cluster units of the type [{M6L8i}L '(a)(6)] (M = Mo, Re, L = S, Se or I, L ' = Cl, Br, I, CN or H2O) exhibit unique optical and electronic properties that make them relevant building blocks for the rational design of nanomaterials using nanoarchitectonic concepts. Photoelectrodes based on Mo-6 and Re-6 clusters with various compositions obtained by deposition of uniform layers of those building blocks onto semiconducting surfaces were recently reported. Remarkably, high quality interfaces were formed not only between building blocks but also between the building blocks and the semiconducting surfaces. On the one hand, layers based on active {Mo6I8i} cluster cores exhibit an ambipolar behavior like carbon nanotube, graphene and transition metal chalcogenides. On the other hand, mixing the two types of {Re6S8i} and {Re6Se8i}-based building blocks enables the creation of micro-(p-n) junctions with enhanced photogenerated current intensity. Herein, we report new advances in the design of photoelectrodes using heterometallic Re4Mo2 cluster-based building blocks. The association of Mo and Re in {Re(4)Mo(2)Q(8)(i)} cluster cores (Q = S and Se) leads to electronic properties and absorption properties significantly different from those of homometallic {Mo6I8i} and {Re(6)Q(8)(i)}. Indeed, beyond different molecular orbital diagrams, the {Re(4)Mo(2)Q(8)(i)} cluster-based units exhibit 22 valence electrons per cluster (VEC) whereas the VEC value for {Mo6I8i} and {Re(6)Q(8)(i)} cluster units is 24. The mixing of rhenium and molybdenum within the same heterometallic cluster enables not only the optical and transport properties of the active layers to be optimized but it also enables the position of the energy levels to be tuned. This appears very appealing for band alignment engineering in order to design optimized photoelectrodes for solar energy conversion. We show herein that the energy levels of the photoelectrodes built on {Re(4)Mo(2)Q(8)} cluster-based layers immobilized on FTO surfaces are compatible with the photoelectrochemical water splitting.

A series of single crystals of CsLa1-& khcy;& Scy;& iecy;& khcy;SiS4 monophasic solid solution (x = 0-1) has been obtained for the first time by high-temperature flux synthesis. Methods of XRD and chemical analysis, absorption and low-temperature (from T = 5 K) luminescent spectroscopy were used. The results of the band scheme calculating using density functional theory correlate with spectroscopy data. One non-elementary d -> f emission band of Ce3+ ions is observed in the region of 520 nm in the luminescence spectra at room temperature at any value of the x parameter. The luminescence decay kinetics of Ce3+ ions upon excitation by a pulsed electron beam, X-ray synchrotron radiation or intracenter photoexcitation is characterized by a nanosecond component. As the parameter x increases, the decay time is reduced from 132 ns (x = 0.005) to 0.88 ns (x = 1). The luminescence decay kinetics upon photoexcitation at x = 0.005-0.12 is characterized by monoexponential decay with tau = 31.4 +/- 0.2 ns. Concentration quenching of the Ce3+ ion photoluminescence is not observed up to the value of the parameter x = 0.12; it only appears at x = 1. The anomalously short decay time of the Ce3+ ions luminescence in CsCeSiS4 upon both X-ray excitation and photoexcitation is associated with concentration quenching. At temperature 5 K, new intense bands at 408 and 688 nm in addition to the Ce3+ emission band observed in the photoluminescence spectra of nominally pure CsLaSiS4 or at the lowest parameter value x = 0.005. These bands correspond to the luminescence of self-trapped excitons (STE) and defects. With increasing x parameter, the STE emission band is reabsorbed by the absorption of Ce3+ ions and is quenched due to the resonance energy transfer STE -> Ce3+ center. Thermoluminescence glow curves of CsLa1-xCexSiS4 irradiated with X-ray at T = 90 K are characterized by several low temperature intense peaks, which indicates a high concentration of charge carrier traps.

In this study, we synthesized La(OH)(3):Eu3+ phosphor using the combustion method with diverse fuels-urea, glycine, and dextrose. Through XRD patterns and Rietveld refinement, we confirmed a hexagonal crystal structure with a P63/m space group for all samples. Our analysis also delved into morphological properties and elemental composition, revealing intriguing differences in particle shapes despite similar sizes, depending on the fuel utilized. Interestingly, the PL excitation and emission characteristics remained consistent among the samples, displaying distinct bands. Spectroscopic investigation of Eu3+ activated La(OH)(3) exhibits the strong red emission which indicated effective energy transfer among rare earth and host. Notably, when excited at 284/290 nm and 395 nm, the phosphor emitted multicolour bands spanning blue to red regions. However, some challenges and shortcomings were observed related to lanthanum hydroxide such as thermal stability, because at higher temperatures samples decompose easily which can limit their high-temperature applications. Additionally, some more issues are with this material i.e. complexity in synthesis, insolubility in water and ageing and exposure to atmospheric CO2 which can change its composition. Despite these challenges, our research focuses on optimizing and improving all these parameters. Addressing these shortcomings of lanthanum hydroxide can be beneficial for the advancement of applications. This impressive emission spectrum underscores the potential of this synthesized phosphor for lighting and display devices. The consistent photoluminescence features across different fuel variations suggest robustness and versatility, indicating promising avenues for future exploration in lighting technology research.

Using XPS and DFT, we have studied a series of octahedral rhenium cluster compounds: ternary thiobromides Re6S4+nBr10-2n, n = 0, 1, 3, 4 and alkali metal salts of anionic complexes [Re6S4+nBr10-n]n-, n = 1-4. These two series contain [Re6S4+nBr4-n] cluster cores, which are the building blocks of both discrete complexes and polymeric compounds, and have the same coordination polyhedron of rhenium atoms. The constancy of the coordination polyhedron of Re reduces the effect of structural differences and allows to study the change in the electronic state of the rhenium atoms of the Re6 metallocluster with increasing number of less electronegative (compared to bromine) sulfur atoms in the cluster core. This change results in the decrease in the binding energy (BE) Re 4f7/2 in the series of anionic complexes [Re6S4+nBr10-n]n-. A similar dependence is observed in the series of ternary thiobromides. Re6S8Br2 falls out of this trend, which is explained by a change in the type of binding of the cluster cores. The BE S 2p3/2 of the sulfide ligands and the BE Br 3d5/2 of the bromide ligands decrease as the number of sulfur atoms in the cluster core and the charge of anionic complexes increases. The difference in BE values for the inner Bri and apical Bra bromide ligands shows that the inner ligands are more covalent and the apical ligands are more ionic. Calculated energies of the Re 4f, S 2p, Br 3d orbitals confirm the general tendency for the energy to decrease as the number of sulfur atoms in the cluster cores increases. Calculation of the atom charges for discrete complexes [Re6S4+nBr10-n]n-, showed that with increasing number of sulfur atoms in the cluster cores, the negative charge of the ligands increases, while the charge of the rhenium atoms remains unchanged. This suggests that the chemical shift of the Re4f binding energy is determined by the potentials of the surrounding atoms (Madelung potential) and that the chemical shift of the ligands depends on the charge of the atom.

The influence of the metal ratio on the geometric characteristics and crystal structures of heterometallic clusters with {Re6−xMoxQ8} cores was studied. Complexes with the same apical ligands form isostructural packings and form the solid solutions.

A detailed study of the Re-S-Br system in the temperature range (650 - 1150 degrees C) of the formation of hexarhenium thiobromides with the general formula Re6S4+nBr10-2n, has revealed the features of phase formation and the factors influencing the production of pure phases. It was found that in reactions with a given stoichiometry 6Re + nS, a mixture of products is usually formed, namely a compound based on a cluster core with the targeted Re/S stoichiometry Re6Sn, an admixture compound with Re6Sn+1 core, and a soluble by-product (3-5% of the total mass), consisting of rhenium bromides and thiobromides. It was found that the composition of the byproduct (Re/S ratio) has a significant effect on the fraction of the admixture compound with higher sulfur content. The slow cooling rate of the reaction mixture, leads to the obtaining of a pure target compound with the {Re6SnBr8-n} cluster core. In the course of the study of the Re-S-Br system, the crystal structure of Re6S7Br4 was solved (space group R-3c, a = 9.5804(2) ?, c = 31.0676(10) ?, V = 2469.48(13) ?3, Z = 6). The study of the thermal behavior showed that the stability of Re6S4+nBr10-2n increases with increasing sulfur content in the cluster core. XPRD data showed that the decomposition of octahedral cluster thiobromides leads to the formation of sulfur-rich phases. This process is accompanied by the release of elemental bromine, metallic rhenium and the formation of soluble by-products with the overall composition "Re2SBrx".

The mixing of rhenium and molybdenum within the same heterometallic cluster enables to modulate optoelectronic properties of the photo-active layers. Such {Re 4 Mo 2 Q 8 }-based photoelectrodes appear promising for the photoelectrochemical water splitting.

The mixing of rhenium and molybdenum within the same heterometallic cluster enables to modulate optoelectronic properties of the photo-active layers. Such {Re4Mo2Q8}-based photoelectrodes appear promising for the photoelectrochemical water splitting.