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Carbon quantum dots have become attractive in various applications, such as drug delivery, biological sensing, photocatalysis, and solar cells. Among these, pH sensing via luminescence lifetime measurements of surface-functionalized carbon dots is one application currently investigated for their long lifetime and autonomous operation. In this article, we explore the theoretical connection between excitation lifetimes and the pH value of the surrounding liquid via the protonation and deprotonation of functional groups. Example calculations applied to m-phenylenediamine, phloroglucinol, and tethered disperse blue 1 are shown by applying a separation approach treating the electronic wave function of functional groups separately from the internal electronic structure of the (large) carbon dot. The bulk of the carbon dot is treated as an environment characterized by its optical spectrum that shifts the transition rates of the functional group. A simple relationship between pH, pKa, and mixed fluorescence lifetime is derived from the transition rates of the protonated and deprotonated states. pH sensitivity improves when the difference in the transition rates is greatest between protonated and deprotonated species, with the greatest sensitivity found where the pKa is close to the pH region of interest. The introduced model can directly be extended to consider multicomponent liquids and multiple protonation states. [ABSTRACT FROM AUTHOR]

We have measured the luminescence shift of the ruby’s R1-line corresponding to the transition pressure of bismuth (Bi) I-II. The Bi sample was loaded in a diamond anvil cell using neon as pressure medium, with small ruby spheres positioned near the Bi sample. Fine compression and decompression were controlled by a double-sided membrane system. Synchrotron x-ray diffraction measurements on Bi and luminescence measurements on ruby were simultaneously collected using an in-line ruby system at the 16-ID-B beamline at the Advanced Photon Source. The Bi I-II transformation is signified by the distinct diffraction patterns, associated with discontinuities in the luminescence shift as a function of time. The determined ruby’s R1-shift is 0.9311 ± 0.007 nm at the Bi I-II transition at 25.8 ± 0.1°C. Together with the previously determined R1-shift relative to the melting pressure of mercury, the calibrations constrain the initial slope of ruby gauge to 1860 ± 3 GPa, compared to 1870 ± 10 GPa in the Ruby2020 gauge. [ABSTRACT FROM AUTHOR]

The low cost and fine‐tunability of the luminescence of copper nanoclusters make them attractive candidates for opto‐electronic, imaging, and sensing applications; their stability, and a precise understanding of the structure–function correlations however, continue to be challenging. A comprehensive chemical etching strategy is developed to synthesize orange, blue, and cyan emitting nanoclusters from a single source of ultrasmall copper nanoparticles; high quantum yields up to ≈34% are realized. Steady state and time‐resolved spectroscopy, electron microscopy, high resolution mass spectrometry, and computational modeling provide critical mechanistic insight into the polychromatic luminescence. A facile method for the fabrication of polymer nanocomposite thin films that sustain and stabilize the luminescent nanoclusters is presented. A subtle variation of the etching strategy without the need to admix multiple components, provides white luminescent thin films with Commission Internationale de l'éclairage (CIE) coordinates, x = 0.35, y = 0.33. The highlights of this work are i) the simple solution synthesis of stable, uniform, and pure ultrasmall Cu nanoparticles, ii) their chemical etching by subtle variations in an optimized protocol to produce highly luminescent, polychromatic nanoclusters, including white‐emitting ones, iii) stabilization of the bright luminescent systems in nanocomposite thin films, and iv) a detailed analysis of the luminescence tuning. [ABSTRACT FROM AUTHOR]

The Paleogene Enping Formation in the Huizhou Sag, Pearl River Mouth Basin, has been identified as a key target for deep oil and gas exploration. However, research on the diagenesis of these deep reservoirs still remains limited. This study evaluated the role played by diagenetic processes on the reservoir quality of the Paleogene Enping Formation in the Huizhou Sag, Pearl River Mouth Basin, from braided river deltas to meandering river deltas. A core observation, thin section examination, cathode luminescence analysis, scanning electron microscopy, mercury penetration, porosity–permeability test, and other analytical methods were performed to analyze the diagenesis and its impact on the physical properties of the deep, low-permeability sandstone reservoirs in the Enping Formation within the study area. It was shown that the reservoir composition maturity of the Paleogene Enping Formation in Huizhou Sag is relatively high, and the reservoir space is dominated by dissolved pores, accounting for more than 48.2%. The deep and ultra-deep clastic reservoirs are typically characterized by "low porosity, low permeability, and strong heterogeneity". In particular, the reservoir space of the deep, low-permeability reservoir of the Enping Formation is significantly affected by diagenesis in which mechanical compaction notably altered the porosity of the Enping Formation reservoir, with a reduction in pore volume ranging from 12.5 to 27.2% (average 18.9%); cementation usually enhances pore reduction by between 2.1 and 28.7% (average 11.7%), while dissolution has resulted in an increase in pore volume ranging from 1.4 to 25.6% (average 10.1%). A further analysis revealed that the deep reservoir type in this region is characterized by "densification", as evidenced by the correlation between reservoir porosity–permeability evolution and hydrocarbon accumulation. [ABSTRACT FROM AUTHOR]

Interfering radiation, such as self-emitting thermal radiation, infrared radiation from heating sources, and combustion gas radiation, significantly impacts the use of optical thermometry. How to improve the precision of temperature measurement in such an environment is a key issue. Therefore, this work aimed to quantitatively analyze the temperature measurement precision of luminescence lifetime thermometry for measuring the temperatures of hot components in environments with interfering radiation. In this paper, based on the quantitative analysis of measurement noise of optical signal and the error propagation theory, we proposed a theoretical model for predicting the temperature measurement precision of luminescence lifetime thermometry. Using blue LED as the interfering radiation source, the temperature measurement experiments of high-temperature surfaces under different interfering radiation intensities were carried out. By comparing the measured precision based on the standard deviation of repeated experiments with the predicted precision of the theoretical model proposed in this paper, the reliability of this theoretical model was verified. The experiments also revealed that the temperature measurement precision was linearly related to the square root of the measured signal intensity (i.e., the sum of luminescence signal and interfering radiation signal). With the increase of the background interfering radiation intensity, although the accuracy of temperature measurement did not change significantly, the measurement noise increases, resulting in a significant increase in random error of measured temperature. This work provides guidance for developing luminescence lifetime thermometers and their applications in environments with interfering radiation. [ABSTRACT FROM AUTHOR]

The timing and causes for erosional events at the Kastrouli (Greece) archeological site – a Late Myceneaen with reuse in later periods – are presented. Two borehole sediment cores (max 6 m depth), collected from the footsteps of the settlement hill plain, were studied. Sedimentary analysis and luminescence dating techniques investigate and identify periods of soil aggradation in this record. Moreover, optically stimulated luminescence (OSL) dating confirmed the concept of an ancient lake during Kastrouli settlement times. Macroscopic overview of the stratigraphic structure for each core, included lithological and textural evaluation of the core sediments, assessments of grain size, and determination of the geochemical and mineralogical composition of the sediments. X-ray powder diffraction (XRPD), X-ray fluorescence (XRF), and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) techniques were applied for the mineralogical and geochemical analysis. OSL ages from seven sediment horizons spanned from the Ottoman period to archaic times. All lithological findings correlate with the results of the electrical tomography survey conducted in same area. Extrapolation of the Logarithmic fitting of the data back in time of prehistoric Late Mycenaean era of Kastrouli verifies a lake deeper than 10 m, with a considerable enhancement in soil aggradation of 1.2 cm/year. Attempts to dry out the area are evidenced by the hydraulic works found in two engineering sinkholes. Sedimentation changes had occurred in the local environment over the last 2500 years, and soil aggradation underwent significant fluctuations in the two studied cores. The Roman period (a wet period) and the Byzantine period experienced high aggradation rates. By contrast, soil aggradation rates in southern Phokis (Kastrouli region) have remained exceedingly low from the Ottoman era (circa 13th century) to the present. In the context of the Phokis case study, it appears that the sedimentation rates, driven by climate, have strengthened anthropogenic activities. [ABSTRACT FROM AUTHOR]

New approach methodologies (NAMs) for predicting embryotoxicity and developmental toxicity are urgently needed for generating human relevant data, while reducing turnover time and costs, and alleviating ethical concerns related to the use of animal models. We have previously developed the PluriLum assay, a NKX2.5-reporter gene 3D model using human-induced pluripotent stem cells (hiPSCs) that are genetically modified to enable the assessment of adverse effects of chemicals on the early-stage embryo. Aiming at improving the predictive value of the PluriLum assay for future screening purposes, we sought to introduce standardization steps to the protocol, improving the overall robustness of the PluriLum assay, as well as a shortening of the assay protocol. First, we showed that the initial size of embryoid bodies (EBs) is crucial for a proper differentiation into cardiomyocytes and overall reproducibility of the assay. When the starting diameter of the EBs exceeds 500 µm, robust differentiation can be anticipated. In terms of reproducibility, exposure to the fungicide epoxiconazole at smaller initial diameters resulted in a larger variation of the derived data, compared to more reliable concentration–response curves obtained using spheroids with larger initial diameters. We further investigated the ideal length of the differentiation protocol, resulting in a shortening of the PluriLum assay by 24 h to 7 days. Following exposure to the teratogens all-trans and 13-cis retinoic acid, both cardiomyocyte contraction and measurement of NKX2.5-derived luminescence were recorded with a similar or increased sensitivity after 6 days of differentiation when compared to the original 7 days. Finally, we have introduced an efficient step for enzymatic dissociation of the EBs at assay termination. This allows for an even splitting of the individual EBs and testing of additional endpoints other than the NKX2.5-luciferase reporter, which was demonstrated in this work by the simultaneous assessment of ATP levels. In conclusion, we have introduced standardizations and streamlined the PluriLum assay protocol to improve its suitability as a NAM for screening of a large number of chemicals for developmental toxicity testing. [ABSTRACT FROM AUTHOR]

This study explores electrochemical etching to form porous silicon (PS), which has diverse biomedical and energy applications. Our objective is to gain new insights and drive significant scientific and technological advancements. Specifically, we study the effect of electrochemical etching of P-type silicon using laser irradiation in a hydrofluoric acid (HF) solution. The formation of the nanoscale PS structure can be successfully controlled by incorporating laser irradiation into the electrochemical etching process. The wavelength and power of the laser influence the formation of nanoporous silicon (NPS) on the surface during the electrochemical etching process. The luminous flux is monitored with the help of a customized integrating sphere system and an LED-based excitation source to find the light flux values distributed across the P-type nanolayer PS wafers. Analysis of the NPS and luminescence characteristics shows that the laser bandwidth controls the band gap energy absorption (BEA) phenomenon during the electrothermal reaction. It is demonstrated that formation of the NPS layer can be controlled in this combined laser irradiation and electrochemical etching technique by adjusting the range of the laser wavelength. This also allows for further precise control of the numerical trend of the luminous flux. [ABSTRACT FROM AUTHOR]

Aspects of the Quaternary sedimentary geology of South-East Asia have proven problematic in terms of interpretation as to the origins and relationships of the surface sediment layers. The MIS 20 large meteorite impact (c., 788 to 785 ka) occurred within mainland South-East Asia, evident from the well-researched 'Australasian Tektite Strewn Field' which extends over at least one tenth of the surface of the Earth. Key questions include: 1) whether the sedimentary impact signature is preserved in the Quaternary sediment cover of the region and 2) whether stratigraphic indicators and dating methods can discriminate meteorite impact-related associations of sedimentary strata, despite subsequent reworking and diagenesis. The importance of the questions raised relate to the search for the impact site, which has not been located conclusively. Moreover, the sedimentary signatures of meteorite impacts are not well known and the descriptions in this study should aid the recognition of impact signatures elsewhere in the world. An hypothesis was developed: Surface Quaternary sediments across a wide area of mainland South-East Asia represent the effects of a regionally significant meteorite impact. Over one hundred sedimentary sections were logged across five countries in mainland South-East Asia. Methods used, defining the stratigraphy and sedimentology, include computed tomography and X-ray scanning, geochemistry, magnetic susceptibility, and environmental luminescence as well as conventional grain size analyses. Luminescence analyses were applied to samples from key strata to provide age constraints and indications of reworking through dose distributional analysis of quartz fractions. The results of the investigation explain the nature of the stratigraphy and relate it specifically to the meteorite impact. In this manner, the strata and sedimentary signatures of the ejecta from a large cosmic impact are defined across a broad region, rather than being described at singular and isolated sections. The novelty is the spatial scale of the investigation which nevertheless remains detailed. A summary model of impact stratigraphy is presented that applies to the regional ejecta blanket covering at least 300,000 km2. Tektites were co-deposited with the ejecta and not introduced by surface processes reworking the deposits. Similar models may be applicable outside of mainland South-East Asia, wherever other large impacts are suspected to have occurred. [ABSTRACT FROM AUTHOR]

Ytterbium (Yb)-doped fibers using aluminophosphosilicate (Yb-APS) host glass offer significant advantages over conventional aluminosilicate (Yb-AS) fibers, such as strong photodarkening resistance, higher RE-ion solubility and lower Numerical Aperture (NA), making them ideal for high-power laser applications. However, achieving optimal performance in Yb-APS fiber fabrication poses various challenges, including maintaining a precise Al3+/P5+ ratio (1:1), minimizing the central dip in the refractive index profile (RIP), ensuring proper dopant distribution, and reducing background loss. We introduce a new fabrication method for Yb-APS fiber to address these challenges. This approach entails first synthesizing amorphous Yb³⁺: AlPO 4 particles, then incorporating them into the fiber core using a hybrid technique that merges Vapor Phase Delivery (VPD) with solution doping (SD). We extensively utilized various materials and optical characterizations, including XRD, FTIR, Raman spectroscopy, FESEM, and XPS, to fine-tune the composition of Yb³⁺: AlPO 4. The optical characterization of the developed preform sample, including absorption, emission, and luminescent lifetime measurements, was conducted to assess the fabrication technique's suitability. The results confirmed the successful incorporation of Yb-ions into the preform core, with peaks consistent with reported values. The fiber's attenuation loss was measured, showing approximately 10 dB/km at 1200 nm. This indicates that the particles dissolved smoothly during preform and fiber processing, resulting in minimal scattering loss in the fiber core. The developed fiber demonstrated NA of 0.1, uniform RIP along the preform length with significant reduction of the central dip formation and improved spectral performance (∼1.7X broader bandwidth) compared with an equivalent Yb-AS fiber. These findings suggest the Yb-APS fiber's overall effectiveness and structural robustness, highlighting the potential of the proposed fabrication method for high-power fiber laser applications. [ABSTRACT FROM AUTHOR]

Lanthanide downconversion nanoparticles (DCNPs) have huge potential in biosensing and imaging applications in the NIR‐II window. However, DCNPs inherently suffer from low quantum efficiency, due to low absorption cross‐section and the restricted doping concentration of lanthanide ions. In this work, a combined strategy for downconversion luminescence in the NIR‐II window is investigated by the integration of Ce3+ ions into the conventional NaYF4: Yb3+, Er3+ DCNPs and incorporation of periodic silver hole‐cap coupled Nanoarrays (Ag‐HCNAs) simultaneously. Over two orders of magnitude, luminescence enhancement is achieved by the combination of optimized Ce3+ doping and plasmonic effects, compared to NaYF4: Yb3+, Er3+ DCNPs immobilized on the glass substrate. Moreover, 3D Finite‐Difference Time‐Domain (FDTD) simulations and time‐resolved luminescence measurements are combined to gain important insights into the mechanism of downconversion luminescence enhancement. The results show that there is a large electric field enhancement between the Ag nanoholes and the Ag hemisphere cap at 980 nm (excitation enhancement), while the lifetime shortening at 1525 nm revealed an increased radiative decay rate and enhanced quantum yield (emission rate enhancement). The strategy for downconversion luminescence enhancement demonstrated in this work holds a significant potential for advancing the next generation biosensing and bioimaging based on DCNPs in the NIR‐II window. [ABSTRACT FROM AUTHOR]

This study introduces a novel approach to addressing environmental issues by developing fish-scale carbon nanoparticles (FSCNPs) with a wide range of colors from discarded fish scales. The process involves hydrothermally synthesizing raw tamban (Sardinella) fish scales sourced from Universal Canning, Inc. in Zamboanga City, Philippines. The optimization of the synthesis was achieved using the response surface methodology with a Box–Behnken design. The resulting FSCNPs exhibited unique structural and chemical properties akin to carbonized polymer dots, enhancing their versatility. The solid-state fluorescence of these nanoparticles can be modulated by varying their concentration in a polyvinylpyrrolidone matrix, yielding colors such as blue, green, yellow, and red-orange with Commission Internationale de l'Eclairage coordinates of (0.23, 0.38), (0.32, 0.43), (0.37, 0.43), and (0.46, 0.48), respectively. An analysis of the luminescence mechanism highlights cross-linking emissions, aggregation-induced emissions, and non-covalent interactions, which contribute to concentration-dependent fluorescence and tunable emission colors. These optical characteristics suggest that FSCNPs have significant potential for diverse applications, particularly in opto-electronic devices. [ABSTRACT FROM AUTHOR]

Macrocyclic Cu(I)–pyrazolate tetramers (Cu4pz4) can fold into compact structures with luminescent Cu4 cores whose emission wavelengths are sensitive to steric effects along the periphery of the macrocycle. Introducing CF3 at the C4 position of 3,5-di-tBu-pyrazolate increases steric crowding that modifies the conformational behavior of the Cu4pz4 complex, highlighted by a low-temperature martensitic transition. Variable-temperature analysis of solid-state luminescence reveal an unexpected blueshifting of emission with rising temperature. [ABSTRACT FROM AUTHOR]

In this work a series of NaPbBi2(PO4)3: 0.09Dy3, xEu3+ (NPbBP) phosphors were prepared. The phase formation and the morphological studies were analyzed using the PXRD data and SEM with EDS image respectively. The band gap value of the NPbBP (3.99 eV) and the NPbBP:0.09Dy3+,0.09Eu3+ (4.14 eV) samples were estimated from the DRS measurements. When exciting the NPbBP:0.09Dy3+, xEu3+ phosphors at 350, 364, 395 nm, the emission spectra exhibited peaks associated with transitions of both Dy3+ (4F9/2 → 6HJ, J = 15/2, 13/2, 11/2, 9/2) and the Eu3+ ions (5D0 → 7FJ, J = 0, 1,2 3). Both the Dexter theory and Reisfield's approximation were employed to investigate the energy transfer mechanism, revealing that dipole–dipole interactions are responsible for transferring the energy from Dy3+ to Eu3+ ions. By exciting at suitable wavelengths (350, 364 and 395 nm) in the NPbBP:0.09Dy3+, xEu3+ phosphors, the emission color could be tuned from neutral white (3769 K) to warm white (2630 K) to reddish orange light (1231 K). Further the luminescence decay curve measurements and emission spectra in the temperature range 303–483 K were specifically performed on the co-doped NPbBP:0.09Eu3+,0.09Dy3+ sample to inspect its temperature-dependent luminescence properties. At 423 K, the phosphor retains 65.5% of its initial value at room temperature. The analysis based on fluorescence intensity ratio (FIR) revealed that the phosphor had good relative sensitivity value of 0.65% K−1. These investigations collectively suggest that the co-doped phosphor holds significant promise for applications in phosphor converted LED and optical thermometry. [ABSTRACT FROM AUTHOR]

Regarding photocatalytic oxidative desulphurization (PODS), titanium oxide (TiO2) is a promising contender as a catalyst due to its photocatalytic prowess and long-term performance in desulphurization applications. This work demonstrates the effectiveness of double-doping TiO2 in silver (Ag) and molybdenum (Mo) for use as a novel catalyst in the desulphurization of light-cut hydrocarbons. FESEM, EDS, and AFM were used to characterize the morphology, doping concentration, surface features, grain size, and grain surface area of the Ag/Mo powder. On the other hand, XRD, FTIR spectroscopy, UV-Vis, and PL were used for structure and functional group detection and light absorption analysis based on TiO2's illumination properties. The microscopic images revealed nanoparticles with irregular shapes, and a 3D-AFM image was used to determine the catalyst's physiognomies: 0.612 nm roughness and a surface area of 811.79 m2/g. The average sizes of the grains and particles were calculated to be 32.15 and 344.4 nm, respectively. The XRD analysis revealed an anatase structure for the doped TiO2, and the FTIR analysis exposed localized functional groups, while the absorption spectra of the catalyst, obtained via UV-Vis, revealed a broad spectrum, including visible and near-infrared regions up to 1053.34 nm. The PL analysis showed luminescence with a lower emission intensity, indicating that the charge carriers were not thoroughly combined. This study's findings indicate a desulphurization efficiency of 97%. Additionally, the promise of a nano-homogeneous particle distribution bodes well for catalytic reactions. The catalyst retains its efficiency when it is dried and reused, demonstrating its sustainable use while maintaining the desulphurization efficacy. This study highlights the potential of the double doping approach in enhancing the catalytic properties of TiO2, opening up new possibilities for improving the performance of photo-oxidative processes. [ABSTRACT FROM AUTHOR]

The persistent luminescent (PSL) phosphors Sr 2- x - y MgSi 2 O 7 : x Eu2+, y Dy3+ (x = 0∼0.08, y = 0∼0.08) were synthesized by a solid-state reaction method in a weak reductive atmosphere of 5%-H 2 /N 2. Comprehensive measurements were carried out to study the effects of Eu2+ and Dy3+ doping amount on the crystal phase, photoluminescence (PL), afterglow decay properties, and trap energy levels. The results indicated that the impurity phases decreased and disappeared, and crystalline grains tended to be larger and denser with the doping amount of Eu2+ and Dy3+ increasing. We shed light on the origination of asymmetric PL peak, concentration quenching of Eu2+ ions, time evolution of PSL specture and chromaticity of Eu2+, Dy3+ co-doped phosphors. Based on the deconvolutions of X-ray photoelectron spectroscopy (XPS) spectra and thermoluminescence (TL) spectra, the types and energy depth of traps in these phosphors were systematically studied. According to the data of PL, PLE, and TL, we deduced a schematic diagram of the energy level and discussed the mechanism of PSL of the phosphors. As Dy3+ dopant increases, the Eu2+, Dy3+ co-doped phosphors not only generate more defects of V O •• and V Sr ʺ, but also introduce Dy Sr • defect with proper trap depth, meanwhile, a thermally assisted tunneling mechanism will gradually dominate during the persistent luminescence, which is responsible for that the phosphor with x = 0.02, y = 0.01 presents the best long afterglow property. [ABSTRACT FROM AUTHOR]

The Murun massif (Aldan shield, Russia) is particularly intriguing due to its group of alkali Ca-(K)-(Na) silicates, which includes many new and rare species. Additionally, it is also of interest for its beryllium mineralization. One of the unique beryllium Ca-(K)-(Na) silicates, odintsovite K2Na4Ca3Ti2Be4Si12O38, was investigated in this study. The aim of this study is to provide new insights into the crystal chemistry and spectroscopic properties of odintsovite. DFT modelling was used to interpret the experimental IR and Raman spectra. Determining the crystal-chemical formula of odintsovite is challenging due to the presence of atoms in different structural positions with varying valence states. The distribution of cations was determined by combining electron probe microanalysis with the results of crystal structure refinement. Luminescence of Eu3+ was observed in odintsovite upon excitation at around 532 nm. Analysis of the luminescence band splitting is related to the 4f–4f transitions in Eu3+ ions. Additionally, upon excitation at around 370 nm, luminescence with a peak at around 410 nm, associated with 5d–4f transitions in Ce3+ ions, was observed. [ABSTRACT FROM AUTHOR]

Biocompatible Carbon dots (CDs) were obtained by the laser irradiation of vegetable carbon placed in a Phosphate-Buffered Saline (PBS) solution. The carbon nanoparticles were generated by a visible and continuum wave (CW) He-Ne laser beam at a 632.8 nm wavelength with 1 mm2 spot, irradiating the carbon target for times of the order of some hours. The CDs generation might be due to thermal effects induced by the prolonged laser irradiation inducing carbon atoms ejection bounded by weak van de Walls forces. Ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR) transmittance and luminescence measurements were employed to study the CDs synthesize. The UV excitation at a 365 nm wavelength induces visible CDs luminescence mainly at about 474 nm wavelength, giving the emitted light a characteristic blue color. The CDs luminescence in biocompatible solutions is presented and discussed in anticipation of possible applications in various sectors, such as radiation detector and material physics, engineering, microelectronics, sensors and, above all, in relation to bio-images from cell cultures and biological tissue as possible applications to the bio-medical field. [ABSTRACT FROM AUTHOR]

Reducing the size of upconversion nanoparticles (UCNPs) down to a few nm yields luminescent materials containing a very small number of emitters. Considering the bottom limit of one activator per particle ultrasmall UCNPs offer an unprecedented platform to study the contributions of the different energy transfers at play in upconversion luminescence. Maintaining detectable emission despite the limited number of emitting ions and the high surface‐to‐volume ratio requires suitable particle architectures. Na(Gd‐Yb)F4:Tm3+ emissive sub‐3 nm diameter β‐phase UCNPs are prepared using a gadolinium‐rich composition in situ mixing of the precursors and a microwave high‐temperature cycling sequence allowing precise control of the particle size and dispersity. These cores are coated with a NaGdF4 inert shell to minimize the deleterious influence of surface quenching (SQ). Time‐resolved luminescence measurements combining standard NIR excitation of the Yb3+ sensitizer and direct UV excitation of the Tm3+ activator are performed to quantify cross relaxation and surface quenching processes. The fine tuning of the number of activators per particle via an optimized synthesis pathway along with the use of an appropriate excitation scheme enabled to provide an accurate analysis of the different mechanisms at play in these model nanoparticles and to characterize the structure of the core‐shell architecture. [ABSTRACT FROM AUTHOR]

In this study, compounds with phenylethynyl (PE) groups introduced at all of the possible positions of the methylene‐bridged structure of the 1,1′‐bi‐2‐naphthol backbone (3‐PE to 8‐PE) were synthesized. Compounds with four or six phenylethynyl groups (3,6‐PE, 4,6‐PE, 5,6‐PE, 6,7‐PE, and 3,4,6‐PE) were also synthesized. The key reaction for the synthesis of these compounds was the Sonogashira reaction using halogen scaffolds. The new transformation methods include (1) selective bromination of the 5‐position of the binaphthyl skeleton and (2) bromination of the 6‐position and then iodination of the 4‐position, followed by the Sonogashira reaction of iodine at the 4‐position and lithiation and protonation of bromine at the 6‐position. The optical properties of the compounds were evaluated. The extension of the π system greatly differed depending on the position of the phenylethynyl group. 4‐PE, 4,6‐PE, and 3,4,6‐PE, in which the phenylethynyl groups were introduced in the extended direction of the naphthalene linkage axis, showed longer absorption and emission wavelengths and higher fluorescence quantum yields than the other compounds. In circularly polarized luminescence measurements, 7‐PE showed a relatively large glum value, an interesting finding that reverses the sense. [ABSTRACT FROM AUTHOR]

A series of Tb3+-activated NaLa(MoO4)2 phosphates were synthesized by solid-state reaction at 800 ℃ for 5 h. Comprehensive characterization of these samples included X-ray diffraction characteristics, luminescence spectra, scanning electron microscopy and analysis of luminescence decay curves. The luminescence analysis indicated that the strongest emissions occurred at wavelengths of 544 nm, 591 nm, and 615 nm. The colour of the fluorescence emission can change from red-orange to red and then to yellow-green light depending on the cvaoncentration ratio of Eu3+ and Tb3+ under different excitations. The CIE chromaticity coordinates demonstrated variability across different color ranges, showcasing the phosphor's capacity for color tuning. The energy yield was 94% when Eu3+ was 0.3 in direct comparison.The versatility in color tuning and high energy efficiency of this bis-molybdate phosphor make it a promising candidate for diverse applications in color display technologies and illumination. [ABSTRACT FROM AUTHOR]

Here, the optical properties of the Nafion polymer membrane containing colloidal CdSe/CdS/ZnS nanocrystals embedded by diffusion have been studied. The CdSe/CdS/ZnS nanocrystals have a core/shell/shell appearance. All experiments were carried out at room temperature (22 ± 2) °C. A toluene solution was used to provide mobility to the active sulfone groups of the Nafion membrane and to embed the nanocrystals inside the membrane. The diffusion process of colloidal CdSe/CdS/ZnS nanocrystals into Nafion proton exchange membrane has resulted in a new molecular complex "Nafion–colloidal CdSe/CdS/ZnS nanocrystals". The kinetics of the nanocrystals embedding into the membrane matrix was investigated using luminescence analysis and absorption spectroscopy techniques. The embedding rate of CdSe/CdS/ZnS nanocrystals into the Nafion polymer membrane was approximately 4·10−3 min−1. The presence of new luminescence centers in the membrane was proved independently by laser emission spectroscopy. The luminescence spectrum of the resulting molecular complex contains intensity maxima at wavelengths of 538, 588, 643 and 700 nm. The additional luminescence maximum observed at the 643 nm wavelength was not recorded in the original membrane, solvent or in the spectrum of the semiconductor nanoparticles. The luminescence maximum of the colloidal CdSe/CdS/ZnS nanocrystals was registered at a wavelength of 634 nm. The intensity of the luminescence spectrum of the membrane with embedded nanocrystals was found to be higher than the intensity of the secondary emission peak of the initial nanocrystals, which is important for the practical use of the "Nafion–colloidal nanocrystals" complex in optical systems. The lines contained in the luminescence spectrum of the membrane, which has been in solution with colloidal nanocrystals for a long time, registered upon its drying, show the kinetics of the formation of the molecular complex "Nafion membrane–nanocrystals". Colloidal nanocrystals located in the Nafion matrix represent an analog of a luminescent transducer. [ABSTRACT FROM AUTHOR]

The preparation of a cocrystal is one of the effective strategies to tune the luminescence properties of organic crystals. In this work, four charge transfer cocrystals were constructed with isomeric substances of amino substituted dimethyl phthalates as the donors and 1,2,4,5-tetracyanobenzene as the acceptor. The emission range of the individual electron donors is from 400 nm to 505 nm, while all cocrystals have their emission redshift exceeding 100 nm. The tunable emission range of the charge transfer cocrystals is from 573 nm to 640 nm. All the obtained four cocrystals contain π–π stacking structures with the presence of π–π and C–H⋯π interactions. Fourier transform infrared spectroscopy and UV-vis spectroscopy demonstrated the presence of charge transfer interactions in the cocrystals. The tuning of the luminescence properties of the cocrystals was explained by the analysis of the crystal packing structure and the intermolecular interaction, and the distribution of frontier orbitals was obtained by DFT calculation. We believe our work is helpful to understand the relationship between the crystal structure and luminescence properties in the charge transfer cocrystals and provide guidance for the modulation of the luminescence properties. [ABSTRACT FROM AUTHOR]

A series of coordination polymers (CPs), some of them featuring an unusual architecture, have been constructed by treatment of RSCH2C≡CCH2SR (R = C6H11L1, t-Bu L2) with CuX (X = Cl, Br, I) and CuX2. The outcome of the reaction of L1 with CuI depends on the metal-to-ligand ratio. Treatment of CuI with L1 in a 2 : 1 ratio affords the luminescent 2D CP [Cu4I4(μ-L1)2]n (CP1), whose grid-shaped network is built upon Cu4(μ3-I)4 cubane-like clusters as secondary building units (SBUs), interconnected via bridging L1 ligands. The use of a 1 : 1 ratio gives a material, whose particularity is the coexistence of two topological isomers within the unit cell. The first one, [{Cu(μ2-I)2Cu}(μ-L1)2]n (CP2), consists of 1D ribbons. The second isomer having a 0D topology, [{Cu(μ2-I)2Cu}(μ-L1)2] D1, is built upon discrete molecular complexes, whose dinuclear [Cu(μ2-I)2Cu] rhomboid-shaped core is spanned by two bridging L1 ligands. Mixing CuBr with L1 in MeCN solution leads to an isostructural material incorporating both 0D [{Cu(μ2-Br)2Cu}(μ-L1)2] complex D2 along with the 1D isomer [{Cu(μ2-Br)2Cu}(μ-L1)2]n (CP3). However, only the 1D CP [{Cu(μ2-Cl)2Cu}(μ-L1)2]n (CP4) results from complexation of L1 with CuCl. A stoichiometry-dependence is also noticed upon treatment of CuI with L2. Conducting the reaction in a 2 : 1 ratio yields the luminescent 2D CP [Cu4I4(μ-L2)2]n (CP5), whereas mixing equimolar amounts of the reactants produces 2D CP [{Cu(μ2-I)2Cu}(μ-L2)2]n (CP6). Structurally similar 2D CPs [{Cu(μ2-X)2Cu}(μ-L2)2]n (CP8 and CP9) result from complexation of L2 on CuBr or CuCl, respectively. Treatment of L2 with an excess of CuBr or CuBr2 in refluxing acetonitrile led to the transfer of Br to the acetylenic triple bond, generating an olefinic halogenated dithioether ligand Bu L3 that coordinates to CuBr to generate a 1D network [{Cu(μ2-Br)2Cu}(CH3CN)(μ-L3)]n (CP9). Using different conditions (propionitrile at 293 K), the reaction of L2 and excess CuBr led to the formation of a 2D network [{Cu(μ2-Br)2Cu}(μ-L2)(μ-L3)]n (CP10) incorporating both L2 and L3 in an alternating manner as assembling ligands. An isostructural chloro-analogue 2D [{Cu(μ2-Cl)2Cu}(μ-L2)(μ-L4)]n (CP11) was obtained using CuCl or CuCl2. The crystallographic work is completed by thermal analyses and investigation of the luminescence properties of CP1 and CP5 at 77 and 298 K. [ABSTRACT FROM AUTHOR]

The high-temperature solid state reaction approach was used to successfully synthesize novel tunable-color emitting Ca 2 LuTaO 6 phosphors with double perovskite structure that were un-doped, single-doped, and co-doped with Bi3+/Sm3+ ions. The crystal structure, microstructure, steady-state photoluminescence, time-resolved luminescence measurements, and thermal quenching features of the material were studied. The density functional theory method was used to compute the band gap of the Ca 2 LuTaO 6 , and Ca 2 LuTaO 6 : Bi3+, Sm3+ phosphors. The blue emission at 407 nm (with 313 nm excitation) is due to the host's luminescence, while the cyan emission at 480 nm (under 365 nm excitation) is related to the distinctive 3P n − 1S 0 transitions (n = 0, 1, 2) of Bi3+. Similarly, efficient red emission is observed in the case of Sm3+ single-doped Ca 2 LuTaO 6 phosphors. In addition, the Ca 2 LuTaO 6 : 0.04Bi3+, 0.05 S m3+ phosphors exhibit energy transfer phenomena and have excellent thermal stability, the fluorescence intensity at 150 °C maintains 73% of that at 25 °C and has a small chromaticity shift. The intense blue emission at 407 nm was effectively converted to cyan, red, and white light through doping with Bi3+ and Sm3+, and the resulting energy transfer. The results obtained confirm that Ca 2 LuTaO 6 : Bi3+, Sm3+ phosphors as a single matrix have great potential for high-power WLED applications. [ABSTRACT FROM AUTHOR]

The climatostratigraphic scale of the Upper Middle Pleistocene in the northwest of the East European Plain contains a number of controversial issues, one of which is the position of the Likhvin (Holstein) Interglacial and lesser warm (interstadial) climatic events. To approach this problem, we have studied two sections of Quaternary deposits, Bolshaya Kosha (a well-known and long-studied natural exposure) and Nazarovo (a new, previously unknown section studied in a borehole), in which warm intervals of the Middle Pleistocene are recognized. In both sections, we performed lithological and paleobiological (carpological, spore-pollen) analyses and luminescence dating. In the Bolshaya Kosha section, seeds of the extinct species Caulinia goretskyi were revealed, which allowed us to attribute the obtained IRSL (ca 250–260 ka) dates to the post-Likhvin Bolshaya Kosha interstadial. The sum of data let us propose that both our IRSL and recently published 230Th/U dates (ca 240–290 ka) underestimate the age by 10–15%, and the post-Likhvin Kosha interstadial deposits were formed in the late MIS 9. In the Nazarovo section, palynological study showed the conditions of a relatively warm interstadial, with a change in the composition of vegetation from northern to middle taiga forests. According to IRSL dating, the section was formed in the MIS 10 late glacial between 330–370 ka. The two studied interstadials bracket the Likhvin (Holstein) Interglacial and sedimentary units in the Bolshaya Kosha section are proposed to have formed in MIS 9e. [ABSTRACT FROM AUTHOR]

In this study, we investigate micrometer-sized NaYF4 crystals double-doped with Yb3+/Er3+ lanthanide ions, designed for temperature-sensing applications. In contrast to previous studies, which focused predominantly on the high-temperature regime, our investigation spans a comprehensive range of both high and ultralow temperatures. We explore the relationship between temperature and the upconversion luminescence (UCL) spectra in both frequency and time domains. Our findings highlight the strong dependence of these spectral characteristics of lanthanide-doped NaYF4 crystals on temperature. Furthermore, we introduce a dual-mode luminescence temperature measurement technique, leveraging the upconversion emission intensity ratio for both green and red emissions. This study also examines the correlation between temperature sensing, energy level disparities, and thermal coupling in Er3+ ions across various temperature scales. Our research contributes to advancing the understanding and application of lanthanide-doped materials, setting a foundation for future innovations in temperature sensing across diverse fields. [ABSTRACT FROM AUTHOR]

The femtosecond laser direct writing technique can allow spatially selective crystallization with suppression of thermal conduction effects. In the case of Al2O3-R2O3 (R = Y, Dy) glass, the polarization-dependent periodic nanostructure with crystallization is self-assembled, however, the formation mechanism of self-assembled nanocrystals in glass remains to be clarified. We focused on Al2O3- Lu2O3 glass prepared by a containerless laser melting method and demonstrated the formation of a nanograting with crystallization by femtosecond laser irradiation. Polarized luminescence measurements of the crystallized region by the pulse bursts with a controllable number of pulses reveal that luminescence anisotropy increased at more than 50 pulses in a burst, suggesting the formation of the nanograting. We have also followed the time variation of birefringence by polarized light imaging to evaluate the time scale for the formation of nanogratings with crystallization. [ABSTRACT FROM AUTHOR]

The possibility of precise movement of YVO4:Yb,Er nanoparticles was studied in this work. Such nanoparticles exhibit upconversion luminescent properties and can serve as an accurate low-invasive probe of changes in the local parameters of the medium (in particular, temperature). Using an atomic force microscope, the substrate region with upconversion nanoparticles deposited from the solution and accompanying residues of the synthesis products was cleaned. The use of mechanical marks on the substrate made it possible to compare the atomic force and optical confocal images of the surface and to register the luminescence from an individual nanoparticle. Elemental analysis and luminescence spectra unambiguously identify the nanoparticle as YVO4:Yb,Er. [ABSTRACT FROM AUTHOR]

An analysis of the luminescence spectra of plasma formed during laser ablation of a gold target immersed in superfluid helium at a laser radiation power density below the breakdown threshold of liquid helium showed that the ionization energy of the Au2+ ion should be no lower than 34 eV. [ABSTRACT FROM AUTHOR]

An analysis of the luminescence spectra of plasma formed during laser ablation of a gold target immersed in superfluid helium at a laser radiation power density below the breakdown threshold of liquid helium showed that the ionization energy of the Au2+ ion should be no lower than 34 eV. [ABSTRACT FROM AUTHOR]

Nowadays, the application scenarios of rare earth doped luminescent materials tend to be refined and complicated. The optical properties of rare earth doped materials are difficult to precisely control via the traditional design and synthesis methods, namely, changing doping concentration or preparative conditions. The aim of this study is to tune the optical transition properties of Er3+ in tungsto-molybdate NaY(Mo x W 1- x O 4) 2 (x = 0, 0.01, 0.1, 0.3, 0.5, 0.7, 0.9, 0.99 and 1.0) phosphors by changing the host matrix. The Er3+ doped continuous tungsto-molybdate solid solution NaY(Mo x W 1- x O 4) 2 phosphors were prepared via a solid state reaction technique at optimized calcination temperatures. The refractive indexes of the obtained solid solution samples were confirmed according to different models and compared. Subsequently, the optical transition intensity parameters, radiative transition rates and intrinsic radiative lifetimes of Er3+ in these solid solution phosphors were calculated in the framework of Judd-Ofelt theory. It was confirmed that the optical transition properties of Er3+ can be greatly tuned by the solid solution composition, and the tuning effects for different transitions are different. To validate the reliability of the Judd-Ofelt calculations, the temperature-dependent emission spectra of two green emissions of Er3+ for different solid solution samples were studied. It was found that the radiative transition rate ratios between two green emissions derived from theoretical calculations and experimental measurements are in reasonable agreement, thus proving that the optical transition calculations are reliable and the optical transition properties of Er3+ in the tungsto-molybdates can be tuned in a large range. This work reminds us of a new route for developing novel luminescence materials based on practical demands. [ABSTRACT FROM AUTHOR]

Hydroxyl radical (•OH), a highly reactive oxygen species (ROS), is assumed as one of the most aggressive free radicals. This radical has a detrimental impact on cells as it can react with different biological substrates leading to pathophysiological disorders, including inflammation, mitochondrion dysfunction, and cancer. Quantification of this free radical in‐situ plays critical roles in early diagnosis and treatment monitoring of various disorders, like macrophage polarization and tumor cell development. Luminescence analysis using responsive probes has been an emerging and reliable technique for in‐situ detection of various cellular ROS, and some recently developed •OH responsive nanoprobes have confirmed the association with cancer development. This paper aims to summarize the recent advances in the characterization of •OH in living organisms using responsive nanoprobes, covering the production, the sources of •OH, and biological function, especially in the development of related diseases followed by the discussion of luminescence nanoprobes for •OH detection. [ABSTRACT FROM AUTHOR]

Lanthanide ion-doped up-conversion (UC) luminescent materials are highly coveted for their utility in diverse applications such as anti-counterfeiting, fluorescence labeling, and temperature sensing. Here, we attempt to adopt SrY2S4 as a novel host lattice for UC luminescence and high-sensitive optical thermometry under near-infrared irradiation. The results show that the single Er3+-doped SrY2S4 samples present their main emissions in green and red regions under 1550 and 980 nm excitations, which correspond to the H11/2/4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. The green to red intensity ratio increases with the Er3+ concentration under both 980 and 1550 nm excitations. The mechanisms of UC luminescence and energy transfer are further systematically investigated by UC spectra and fluorescence decay dynamics. Furthermore, the non-contact temperature sensing performance of the SrY2S4:10%Er3+ sample is explored via employing fluorescence intensity ratio (FIR) technology. At an excitation of 980 nm, the maximum absolute sensitivity (SA) reaches 7.5 × 10−3 K−1 at 480 K. By utilizing a much safer excitation laser of 1550 nm, the maximum SA achieves 8.4 × 10−3 K−1 at 450 K, with a high and stable SA of more than 7.9 × 10−3 K−1 over a broad temperature range of 360–570 K. The relative sensitivity is 1.06% and 1.01% K−1 under 980 and 1550 nm excitations, respectively. These results indicate that the ternary sulfide SrY2S4 can be adopted as a novel host to achieve promising UC luminescence and thermal sensing performance. [ABSTRACT FROM AUTHOR]

This work investigates the proposed enhanced efficacy of photodynamic therapy (PDT) by activating photosensitizers (PSs) with Cherenkov light (CL). The approaches of Yoon et al. to test the effect of CL with external radiation were taken up and refined. The results were used to transfer the applied scheme from external radiation therapy to radionuclide therapy in nuclear medicine. Here, the CL for the activation of the PSs (psoralen and trioxsalen) is generated by the ionizing radiation from rhenium-188 (a high-energy beta-emitter, Re-188). In vitro cell survival studies were performed on FaDu, B16 and 4T1 cells. A characterization of the PSs (absorbance measurement and gel electrophoresis) and the CL produced by Re-188 (luminescence measurement) was performed as well as a comparison of clonogenic assays with and without PSs. The methods of Yoon et al. were reproduced with a beam line at our facility to validate their results. In our studies with different concentrations of PS and considering the negative controls without PS, the statements of Yoon et al. regarding the positive effect of CL could not be confirmed. There are slight differences in survival fractions, but they are not significant when considering the differences in the controls. Gel electrophoresis showed a dominance of trioxsalen over psoralen in conclusion of single and double strand breaks in plasmid DNA, suggesting a superiority of trioxsalen as a PS (when irradiated with UVA). In addition, absorption measurements showed that these PSs do not need to be shielded from ambient light during the experiment. An observational test setup for a PDT nuclear medicine approach was found. The CL spectrum of Re-188 was measured. Fluctuating inconclusive results from clonogenic assays were found. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, yet the cellular and molecular mechanisms underlying the AF substrate remain unclear. Isolevuglandins (IsoLGs) are highly reactive lipid dicarbonyl products that mediate oxidative stress-related injury. In murine hypertension, the lipid dicarbonyl scavenger 2-hydroxybenzylamine (2-HOBA) reduced IsoLGs and AF susceptibility. We hypothesized that IsoLGs mediate detrimental pathophysiologic effects in atrial cardiomyocytes that promote the AF substrate. Using Seahorse XFp extracellular flux analysis and a luminescence assay, IsoLG exposure suppressed intracellular ATP production in atrial HL-1 cardiomyocytes. IsoLGs caused mitochondrial dysfunction, with reduced mitochondrial membrane potential, increased mitochondrial reactive oxygen species (ROS) with protein carbonylation, and mitochondrial DNA damage. Moreover, they generated cytosolic preamyloid oligomers previously shown to cause similar detrimental effects in atrial cells. In mouse atrial and HL-1 cells, patch clamp experiments demonstrated that IsoLGs rapidly altered action potentials (AP), implying a direct effect independent of oligomer formation by reducing the maximum Phase 0 upstroke slope and shortening AP duration due to ionic current modifications. IsoLG-mediated mitochondrial and electrophysiologic abnormalities were blunted or totally prevented by 2-HOBA. These findings identify IsoLGs as novel mediators of oxidative stress-dependent atrial pathophysiology and support the investigation of dicarbonyl scavengers as a novel therapeutic approach to prevent AF. [ABSTRACT FROM AUTHOR]

Featured Application: The approach presented in this work may be applicable to imaging technology relevant to assessing oxidative stress. Delayed luminescence from organisms informs oxidative stress that may be modulable by external stimulations. In the absence of external stress causing delayed luminescence, organisms may produce spontaneous ultraweak photon emission due to the residual oxygen demand. To better understand the oxidative state of an organism, it is desirable to acquire the delayed luminescence to reach the phase wherein the ultraweak photon emission resides. This, however, is challenging due to the significant difference in the order of magnitude of the photon counts between the two types of photon emission. Conventional time-gated measurement requires a high dynamic range to assess the noise-level photon emission, whereas simple long exposure can miss the kinetics of luminescence. There may be a compromise to be made between robustly acquiring the decay kinetics of the delayed luminescence and reliably acquiring the noise-laden spontaneous photon emission. We demonstrate an irradiation-acquisition interleaved time-integrated imaging approach that may enable the reliable acquisition of slow-decay delayed luminescence down to the level of ultraweak photon emission. Repetitive irradiation was interleaved with a gradually increased time of acquisition to assess the integrated time course of the post-irradiation luminescence. Such instrument configuration performed on yeast facilitated the use of time differentiation to assess the delayed luminescence down to the noise-level ultraweak photon emission at the expense of the total time of acquisition. [ABSTRACT FROM AUTHOR]

The synthesis and luminescence analysis of Tb3+-activated phosphors were reported. Y2SiO5 phosphors were synthesized by a modified solid-state reaction method with a variable doping concentration of Tb3+ ion (0.5–2.5 mol.%). As synthesized, the phosphors were characterized by X-ray diffraction (XRD) analysis. The XRD pattern confirmed the monoclinic structure of the prepared phosphor. Scanning electron microscopy and High-Resolution Transmission Electron Microscopy (HRTEM) studies revealed nearly uniform particle size distribution in the prepared phosphors. The photoluminescence excitation spectra of the Y2SiO5:Tb3+ (0.5–2.5 mol.%) phosphor displayed one broad, intense peak at 258–277 nm. When excited at the 258 nm wavelength, the phosphors showed emission peaks at 553 nm (5D4 → 7F5), 544 nm (5D4 → 7F5) and 489 nm (5D4 → 7F6). The 1931 CIE (x,y) chromaticity coordinates showed the distribution of the spectral region calculated from the photoluminescence emission spectra. The values of x = 0.25 and y = 0.46 were very close to light green emission. Therefore, the prepared phosphor is very useful for light-emitting diode (green component) applications. [ABSTRACT FROM AUTHOR]

In this study, a combination of X-ray excited optical luminescence (XEOL), time-resolved XEOL (TR-XEOL) and the Hanbury-Brown and Twiss (HB-T) interferometer at the Taiwan Photon Source (TPS) 23A X-ray nanoprobe beamline for exploring quantum materials is demonstrated. On the basis of the excellent spatial resolution rendered using a nano-focused beam, emission distributions of artificial micro-diamonds can be obtained by XEOL maps, and featured emission peaks of a selected local area can be obtained by XEOL spectra. The hybrid bunch mode of the TPS not only provides a sufficiently high peak power density for experiments at each beamline but also permits high-quality temporal domain (~200 ns) measurements for investigating luminescence dynamics. From TR-XEOL measurements, the decay lifetime of micro-diamonds is determined to be approximately 16 ns. Furthermore, the XEOL spectra of artificial micro-diamonds can be investigated by the HB-T interferometer to identify properties of single-photon sources. The unprecedented strategy of combining XEOL, TR-XEOL and the HB-T interferometer at the X-ray nanoprobe beamline will open new avenues with significant characterization abilities for unraveling the emission mechanisms of single-photon sources for quantum materials. [ABSTRACT FROM AUTHOR]

Cypridina luciferin (CypL) is a marine natural product that functions as the luminous substrate for the enzyme Cypridina luciferase (CypLase). CypL has two enantiomers, (R)- and (S)-CypL, due to its one chiral center at the sec-butyl moiety. Previous studies reported that (S)-CypL or racemic CypL with CypLase produced light, but the luminescence of (R)-CypL with CypLase has not been investigated. Here, we examined the luminescence of (R)-CypL, which had undergone chiral separation from the enantiomeric mixture, with a recombinant CypLase. Our luminescence measurements demonstrated that (R)-CypL with CypLase produced light, indicating that (R)-CypL must be considered as the luminous substrate for CypLase, as in the case of (S)-CypL, rather than a competitive inhibitor for CypLase. Additionally, we found that the maximum luminescence intensity from the reaction of (R)-CypL with CypLase was approximately 10 fold lower than that of (S)-CypL with CypLase, but our kinetic analysis of CypLase showed that the Km value of CypLase for (R)-CypL was approximately 3 fold lower than that for (S)-CypL. Furthermore, the chiral high-performance liquid chromatography (HPLC) analysis of the reaction mixture of racemic CypL with CypLase showed that (R)-CypL was consumed more slowly than (S)-CypL. These results indicate that the turnover rate of CypLase for (R)-CypL was lower than that for (S)-CypL, which caused the less efficient luminescence of (R)-CypL with CypLase. [ABSTRACT FROM AUTHOR]

Long-term continuous deposits and well-preserved thick loess sections are natural archives for the reconstruction of global climate change. However, the loess sections are often discontinuous owing to soil erosions and accumulations. This study aimed at reconstructing long-term continuous paleoclimatic records by integrating the target sections of two typical loess sequences in northeast (NE) China. One section, the Dajiugang (DJG) section, was investigated and sampled, and the Sanbahuo (SBH) section was used as the target for integrating and reconstructing the paleoclimate. Sedimentary, pedogenesis, and luminescence dating analyses were conducted to analyze the potentials for reconstructing the paleoclimate by integrating two typical loess sections. The results indicated that the paleoclimate records derived from the DJG section can be used to reconstruct the continuous paleoclimate of NE China by integrating them with the SBH section. The paleoclimate information inferred from the DJG section could impute paleoclimate data from 71 to 11.7 ka, which were missing in the SBH section. The paleoclimate of NE China generally consisted of three periods from 71 to 11.7 ka: cold and dry from 29 to 11.7 ka, alternately cold and warm from 57 to 29 ka, and warm and wet to cold and dry from 71 to 57 ka. Integrating the target loess sections can contribute to reconstructing regional long-term continuous paleoclimate records where discontinuous loess sequences occurred. [ABSTRACT FROM AUTHOR]

Two new metal–organic frameworks (MOFs), namely, {[Zn(HL)(bpea)]·DMF}n (Zn-MOF-1) and {[Co(HL)(bpea)]·DMF}n (Co-MOF-2) (H3L = 3-(3,5-dicarboxybenzyloxy)benzoic acid, bpea = 1,2-di(pyridyl)ethane), were obtained by the reaction of H3L and N-containing ligand bpea with Zn(NO3)2·6H2O and Co(NO3)2·6H2O, respectively. The isomorphic Zn-MOF-1 and Co-MOF-2 featured a 3D penetrating framework with different stabilities, luminescence, and catalytic properties. Luminescence measurement indicated that Zn-MOF-1 could be used to detect Al3+ through a turn-on effect with a detection limit of 0.42 μM. The sensing mechanism experiments showed that the enhanced luminescence of Zn-MOF-1 toward Al3+ may be due to the weak interaction between Al3+ and Zn-MOF-1 and the absorbance-caused enhancement (ACE) mechanism. Meanwhile, both Zn-MOF-1 and Co-MOF-2 showed interesting CO2 adsorption properties and could catalyze the cycloaddition of CO2 to epoxides resulting in 96 and 92% ideal products within 12 hours, respectively. They can be cycled up to 5 times without significant loss of catalytic efficiency. [ABSTRACT FROM AUTHOR]

Abstract—We have considered the interaction of an exciton mode with photonic modes in a GaN structure several pm in size. A technique for obtaining spectra from such structures has been demonstrated. The cavity shape and dimensions most optimal for efficient light/matter interaction have been selected. The theoretical spectrum for the selected cavity has been obtained and analyzed. [ABSTRACT FROM AUTHOR]

The current research aims to develop an optically active, thermally luminescent, and radiation-shielding glass resources. For that, we have planned to develop a glasses of the chemical composition Ba(25-x)La15Si60Nix (where, 'x' = 0, 0.2, 0.4, 0.6, 0.8 & 1.0 mol%). There after the developed glasses are planned for structure, physical, mechanical, radiation shielding, optical and thermoluminescence characterization. The XRD & SEM studies reveal the glassy behavior. The EDS analysis signifies the chemical constitutes with atomic weight %. The physical properties such as density (~ 2.625 gm/cm3), molar volume (~ 48.48 cm3 mol−1) and refractive index (1.649) of glasses are evaluated. The DTA studies of glasses reveal the GTT (~ 429.5 °C) and thermal stabilities (1.593) evolutions are purely function of Ni2+ ions. Using ultrasonic velocities of the test glasses, the glasses' micro-hardness (~ 2.82 GPa) was evaluated. Radiation shielding properties such as RPE (~ 36.55%) and MAC (~ 16.556) reveal the shielding behavior is purely a function of Ni2+ ions. Using the optical absorption spectra, the bandgap (~ 1.21 eV) of the glasses evaluated. These values also purely function of Ni2+ ions. Using the photoluminescence spectra the luminescence analysis of glasses studied. The variations in values of emission cross section (~ 1.21 × 109, cm2) and Chromacity colour co-ordinates also suggesting emission range of glasses is purely function of Ni2+ ions. The TL properties are studied at 0 and 50 kGy gamma irradiation dose range. The frequency factor (~ 3.062 × 1021, S−1) and A.E. (~ 1.798 eV) of glasses were evaluated. This reveals that the TL behavior of glasses is a purely function of Ni2+ ions. Overall, the NSBL glasses prepared are mechanical hard, TL effective, optical and radiation shielding resources. [ABSTRACT FROM AUTHOR]

Well-defined NaY(WO 4) 2 :Tb3+ nanoflowers were prepared through the controllable structural transition of hydroxyl sodium yttrium tungstate precursor, which exhibit a fascinating luminescent property as activated by Tb3+ dopant. NaY(WO 4) 2 :Tb3+ nanoflowers were systematically characterized with a series of tests including XRD, SEM, FT-IR, TG-DTA, UV–Vis, and PL. XRD analyses indicate that NaY(WO 4) 2 :Tb3+ crystalizes in the scheelite structure with broadened diffraction peaks and expanded cell volume with increasing Tb3+ content as revealed by Rietveld refinement. FT-IR and TG-DTA results show that NaY(WO 4) 2 :Tb3+ is formed via the structural transition of hydroxyl sodium yttrium tungstate at calcination temperature above 600 °C. UV–Vis test discloses the bandgap red-shift of NaY(WO 4) 2 via doping Tb3+ ions. Noticeably, PL measurement discloses the green luminescence of NaY(WO 4) 2 :Tb3+ attributable to 5D 4 →7F 5 transition with the optimal Tb3+ doping content of 13 mol%, which manifests the effective energy transfer from WO 4 2− groups to Tb3+ ions and reveals relatively good thermal stability. Furthermore, the tunable color emission from blue to green to yellowish green can be achieved in flower-like NaY(WO 4) 2 :Tb3+ phosphors by controlling the doping content of Tb3+ ions, which may provide promising application in the field of multicolor lighting and displays. The structural transition of hydroxyl sodium yttrium tungstate to NaY(WO 4) 2 :Tb3+ through calcination treatment, which reveals the bandgap narrowing and lattice expansion of NaY(WO 4) 2 due to Tb3+ substituting for Y3+. NaY(WO 4) 2 :Tb3+ phosphors demonstrate a dominant green luminescence attributable to 5D 4 →7F 5 transition with the optimal Tb3+ doping content of 13 mol%, which manifests the effective energy transfer from WO 4 2− groups to Tb3+ ions. Furthermore, the tunable color emission from blue to green to yellowish green can be achieved in flower-like NaY(WO 4) 2 :Tb3+ phosphors by controlling the doping content of Tb3+ ions, which may provide promising application in the field of multicolor lighting and displays. [Display omitted] • The hydroxyl sodium yttrium tungstate with flower-like morphology was prepared by a simple hydrothermal process. • NaY(WO 4) 2 :Tb3+ nanocrystals with scheelite structure was obtained by calcinating hydroxyl sodium yttrium tungstate. • Tb3+ substituting for Y3+ results in the lattice expansion of NaY(WO 4) 2 as predicted by Vegard's law. • The bandgap energy of NaY(WO 4) 2 :Tb3+ nanocrystals showed a red-shift below the doping content of 13 mol% of Tb3+ ions. • The tunable color emission from blue to green to yellowish green can be achieved in NaY(WO 4) 2 :Tb3+ phosphors. [ABSTRACT FROM AUTHOR]

In this present paper, the LaVO4:Eu3+,Cr3+ (LV:Eu,Cr) red-orange phosphors are introduced in WLED fabrication. The LV:Eu,Cr phosphor is synthesized with high-temperature solid-phase reaction. The luminescence properties of the phosphor are monitored with ultraviolet-visible and near-infrared (UVvis-NIR) measurements. The heat generating in the phosphor sample is also investigated with different power densities of the 980 nm laser. The phosphor exhibits absorption bands at 254 nm and 316 nm, suitable for UV light-emitting diodes (UV LED) applications. The Cr3+ concentrations have noticeable effects on the luminescence of the phosphor. The increasing Cr3+ dosage initiates reduction in Eu3+ emission intensity and luminescence lifetime average. The heat-activated amount in the phosphor is also significant with the higher concentration of Cr3+ ions. When using the LV:Eu,Cr phosphor in white light-emitting model (WLED), the dominant red-orange emission centered at 595 nm is observed, in addition to the blue peak at 453 nm. The luminosity, color rendition, and color uniformity of the WLED light are also discussed. The findings indicate that the phosphor can be combined with other high-efficiency blue and green phosphors to obtain the improved color rendition and luminous performances and used in heatcreating optical applications. [ABSTRACT FROM AUTHOR]

New series of Ho3+/Yb3+ and Tm3+/Yb3+ codoped Na5Rb7Sc2(WO4)9 phosphors have been prepared by a conventional solid state reaction method. A powder XRD study has revealed that all the synthesized tungstates are isostructural and crystallize in the trigonal crystal system (sp. gr. R32, Z = 3). Upconversion luminescence in the 460–850 nm spectral range, associated with transitions in Ho3+ or Tm3+ ions, has been detected under 980 nm laser diode excitation. The optimal Ho3+/Yb3+ and Tm3+/Yb3+ ratios have been determined. Possible mechanisms of energy transfer between lanthanide ions have been discussed. The luminescence characteristics of the representative samples, Na5Rb7Sc1.925Yb0.045Ho0.03(WO4)9 and Na5Rb7Sc1.9Yb0.09Tm0.01(WO4)9, have been studied at 298–498 K to evaluate their temperature measurement performance. The calculated values of the absolute and relative sensitivities indicate that the studied tungstates are promising phosphors for non-contact thermometry. [ABSTRACT FROM AUTHOR]

Ag2S nanoparticles (NPs) are attractive materials for wide application in catalysis, solar cells, and energy storage, owing to their low toxicity, tunable electronic properties, narrow bandgap, and light emission. However, in situ and operando studies are required for a deeper understanding of the crystallisation pathways that govern their structural-related properties and changes during operation, for example, during galvanostatic discharge–charge (GDC) in sodium-ion batteries (SIBs), to improve their cycling performance. This work presents new strategies for the synthesis of α-Ag2S NPs applying aqueous or polyol-assisted methods, and using double- or single-source based approaches. Double-source polyol synthesis was used to demonstrate the effect of reaction time, capping agent, and reaction temperature on the Ag2S particle size. Insights into Ag2S formation processes were obtained by in situ analysis of changes in turbidity and of infrared or UV/vis transmittance spectroscopy, in addition to synchrotron-based X-ray diffraction. After testing the application of Ag2S NPs as SIB electrodes, a proof-of-principle experiment is presented, demonstrating the feasibility of measuring operando luminescence spectra to monitor changes in the electrode structure during GDC cycling. The in situ results showed the influence of synthesis parameters on the nucleation process, resulting in compact and hollow NPs of ∼5–400 nm. Ag2S NPs showed an initial capacity of 520 mA h g−1 in SIBs. Despite an expected large capacity loss due to e.g. the solid electrolyte interphase (SEI) formation, the capacity was found to be stable, and operando luminescence measurements indicated the formation of Na(Ag3S2) and elemental Ag during cycling. Since several battery-electrode materials are optically active, operando luminescence measurements during cycling significantly impact the monitoring of structural changes owing to their high availability and independence from synchrotron radiation. [ABSTRACT FROM AUTHOR]

This work presents an analysis of the spectroscopic properties of glass and glass ceramics co-doped with Ni2+ and Er3+ ions. Spectroscopic analysis showed the embedding of nickel ions in the gamma-gallium oxide nanocrystals as a result of heat treatment of the glass samples. Analysis of the luminescence properties of the obtained samples under 940 nm and 980 nm pump excitation allowed the selection of a proper Er3+ ions concentration for further optical fiber fabrication. Measured lifetime results of glass-ceramics samples confirm energy transfer from nickel ions to erbium. In the process of drawing the optical fiber, it was possible to create a transparent nanocrystalline glass-ceramic core, as confirmed by XRD results. The produced glass-ceramic optical fiber was characterized by broadband emission in the range from 1100 nm to 1650 nm corresponding to the 3T 2 (3F) →3A 2 (3F) (Ni2+) and 4I 13/2 → 4I 15/2 (Er3+) transitions for 940 nm and 980 nm pump excitation. The Er3+ to Ni2+ ions emission intensity ratio of the fabricated glass-ceramic fiber was estimated to be 0.84 and 7.14 for 940 nm and 980 nm optical pumps, respectively. [ABSTRACT FROM AUTHOR]