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The crystal structure and morphology of Ce(3+) -doped SrSnO3 materials prepared using the solid-state reaction method were extensively characterized using experimental techniques. X-Ray diffraction results show that the cerium substitution of strontium does not change the structure of the strontium stannate. Raman spectroscopy was used to investigate the microstructures and lattice vibrations. Environmental scanning electron microscopy images showed that phosphors aggregate and their particles form irregular shapes. SrSnO3 exhibits an intense green emission with a broad band originating from the 5d(1)  → 4f(1) transition of cerium. It was observed that, after exposure to beta-irradiation, the glow curve of this material has two broad thermoluminescence peaks, one centered at ~ 127°C and the other at ~ 245°C for a heating rate of 5 K/s. The kinetic parameters, which include the frequency factor and the activation energy of the material, were calculated using Chen's method, after beta-irradiation. The fading and reusability of the phosphor were also studied and it was found that the phosphor is suitable for radiation dosimetry., (Copyright © 2014 John Wiley & Sons, Ltd.)

Studies enhancement of luminescence by pulse laser annealing of ion-implanted europium in sapphire and silica. Method of the study; Results and discussion; Conclusion.

The phosphors of calcium stannate activated with individual trivalent rare-earth element (REE) ions (Neodymium III, Europium III, Terbium III, Dysprosium III, and Samarium III) were synthesized by high-temperature solid-state reaction (SSR), and their characterization and luminescent properties were investigated. The crystal structures and morphologies of the resultant materials were well characterized by experimental techniques such as X-ray powder diffraction (XRD) and environmental scanning electron microscopy (ESEM). The XRD results display that the rare-earths substitution of Calcium II does not change the structure of calcium stannate host. Obviously, the ESEM image exhibits that phosphors aggregate and their particles with irregular shape exist. The calcined powders of the Europium III, Neodymium III, Samarium III, Dysprosium III, and Terbium III ions doped in calcium stannate exhibits bright red, reddish orange, yellowish, orange white, and green light, respectively. Although there is some intrinsic emission ranging from UV to near-infrared (NIR) due to the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the trivalent rare-earth states. The emission spectrum from undoped-calcium stannate phosphor is characterized by two broad bands centered at ∼800 and ∼950 nm. The shapes of the emission bands are different for each dopant. The sharp emission properties show that the calcium stannate is a suitable host for rare-earth ion-doped phosphor material. Furthermore the influence of different rare-earth dopants, that is, Europium III, Neodymium III, Samarium III, Dysprosium III, and Terbium III, on thermally stimulated luminescence (TSL) of calcium stannate phosphor under the beta irradiation was discussed. Among these trivalent rare-earth-doped phosphors samarium-doped material showed maximum TSL sensitivity with favorable glow curve shape. [ABSTRACT FROM PUBLISHER]

Cathodoluminescence (CL) and optical absorption properties of rhodonite natural silicate mineral were investigated. CL spectra show an intense Mn2+ luminescence band, which occurs as broad-band emission in the orange-to-red range. The broadness of the emission is explained by strong interaction of 3d ions with the surrounding crystal field, which is strongly affected by lattice and atomistic vibrations of the ligands. Rhodonite rock exhibits luminescence maxima at 310, 425, and 626 nm. The Raman spectrum of rhodonite (from Turkey) is characterized by an intense band at about 668 cm−1 assigned to ν4 bending mode and showed additional bands exhibiting loss of degeneracy of the SiO4 units. A strong band at 408 cm−1 is attributed to the ν2 bending bond. [ABSTRACT FROM PUBLISHER]

Abstract: Rare earths, especially Dy or Tm doped CaSO4 phosphors are actively studied. They have high sensitivity, a large dynamic range, thermal stability and ease of preparation. Nevertheless, they can be enhanced by inclusion of lithium and this study reports some effects of lithium co-dopant on the TL and radioluminescence (RL) emissions of two TL phosphors. Addition of Li as a co-dopant ion was made either during chemical preparation of the phosphors, or as a binder component mixed with the basic phosphors matrix during the process of pressing and sintering the TLD pellets. [Copyright &y& Elsevier]

Abstract: Copper nanoparticles have been formed in a zinc oxide (ZnO) substrate by Cu implantation at 160keV. The implant layer shows amorphised behaviour as monitored by the RBS data and optical absorption indicates the surface plasmon resonance peak characteristic of copper nanoparticles. There is nonlinear optical absorption from the Cu nanoparticles. There are numerous changes in the luminescence responses which include a variety of green and yellow emission bands. During excitation there were changes in the cathodoluminescence intensity and lifetime influenced by the surface events, including some unusual features, which may be considered in terms of interactions with surface water and ice. Radioluminescence signals oscillate between the normal emission bands and the wide red line emission from free Zn. Overall ZnO is, therefore, an unexpectedly interesting host for dispersed Cu nanoparticles, not least because the optical features may be compatible with the semiconductor aspects of ZnO. [Copyright &y& Elsevier]

Several methods have been developed in the analysis of the thermoluminescence glow peaks, and in particular when applied to thermoluminescence (TL) dosimetry and TL dating of archaeological and geological minerals. Some of these methods are identical to those developed for the study of thermal desorption. Such a method is called half-width method where a shape factor is introduced. Recently TL decay and thermal desorption process have been studied using a nonextensive formalism, namely Tsallis thermostatistics. In the present work, we consider the half-width method because it is the easiest one to estimate the activation energy. Importantly, we give the generalized form of the activation energy for all order of kinetics. We also investigate the influence of the nonextensivity on the shape factor parameter and on the activation energy. [Copyright &y& Elsevier]

An isonicotinic acid N-oxide Mn(II) compound was synthesized and characterized on the basis of elemental analysis and X-ray crystallography. In the complex, Mn(II) ions are coordinated by six water molecules, and the coordination number of the Mn(II) ion is six. FTIR spectra of the compound free isonicotinic acid N-oxide (INO) have been recorded in the range 4000–400 cm−1. Cathodoluminescence (CL) spectra from the Mn(II) complex have been recorded. The luminescence data were interpreted in terms of the emission band at 480 nm. The green luminescence (∼480 nm) arises from the Mn2+ transition 4T1 (4G) → 6A1 (6S). It shows weak vibronic structure, short lifetimes less than 250 μs, and indicates that Mn2+ is octahedrally coordinated, occupying sites with similar distortions. The lifetime and intensity of the signal is temperature dependent, and the parameters are reported for the 480 nm emission line. [Copyright &y& Elsevier]

The presence of copper nanoparticles in alumina and silica modifies their luminescence, and the changes in spectra are influenced by variations in the nanoparticle size distributions. Luminescence signals are sensitive to the total defect population. Thus the luminescence not only reflects changes caused by thermal annealing, which can modify both intrinsic defects and the copper nanoparticles, but also responds to the method of preparation of thin film layers. Copper nanoparticle influence on luminescence is reported both for ion-implanted bulk silica and for copper in pulsed laser deposition within alumina. Luminescence thus potentially offers a non-destructive monitor of the layer quality, reproducibility and growth conditions, as well as the state and size of the copper nanoparticles. [ABSTRACT FROM AUTHOR]

Pure and a series of BaSi 2 O 5 :RE3+ (RE = Dy, Sm) phosphors varying with the substitution of Ba2+ were prepared using a gel-combustion method. X-ray diffraction results confirmed that all samples exhibited an orthorhombic structure. FT-IR spectra showed that the samples consist of BaCO 3 , SiO 2 network and the presence of OH groups. The photoluminescence spectrum of non-doped BaSi 2 O 5 showed a broad-band emission peak at 520 nm. The analysis of photoluminescence emission and comparison of the chromaticity diagrams of BaSi 2 O 5 :Dy3+ and BaSi 2 O 5 :Sm3+ phosphors were presented, and their implications are also discussed. The optimum quenching concentrations and critical distances of Dy3+ and Sm3+ ions in the BaSi 2 O 5 were 2mol%, 22.57 Å and 1 mol%, 28.44 Å, respectively. The investigation of concentration quenching behaviour, fluorescence decay curves, and decay time indicates that the dominant mechanism type leading to concentration quenching was governed by electric dipole-dipole interactions. The concentration dependence of intensity ratio of yellow-blue emission indicated that the emission of BaSi 2 O 5 :Dy3+ phosphors fell in the white light region tuning the blue and yellow components. BaSi 2 O 5 :Sm3+ phosphors may allow one to consider as potential orange-red-emitting phosphors. Image 1 • Sm3+ and Dy3+ activated BaSi 2 O 5 phosphors are synthesized by gel combustion method. • The crystalline sizes of synthesized phosphors are calculated. • First ever report on concentration quenching mechanism in a Sm3+ and Dy3+ doped BaSi 2 O 5. • Photoluminescence and decay curve properties of pure and Sm3+ and Dy3+ activated BaSi 2 O 5 phosphors are discussed. [ABSTRACT FROM AUTHOR]

GdAl 3 (BO 3) 4 :Dy3+, Sm3+, Eu3+, and Tb3+ samples were successfully achieved via a sol-gel combustion method. The observed XRD analysis confirms the formation of the desired GAB host, indicating rhombohedral structures that agree well with JPCD card number 72–1985. The FTIR analyses show the detection of B − O stretching and B − O − B bending modes as well as Al − O and Gd − O bonds in the phosphor samples. Energy dispersive spectroscopy (EDS) analysis reveals that Sm, Eu, Dy, and Tb have been successfully doped into GdAl 3 (BO 3) 4. The observed broad intrinsic luminescence band can be caused by oxygen-induced luminescence defects in the GAB host with hydrous precursors. The luminescence properties of rare earth ion-doped GdAl 3 (BO 3) 4 samples are analysed by photoluminescence spectra, showing their optimal doping concentrations and critical distances of Dy3+, Eu3+, Sm3+ and Tb3+ are 2 wt% − 25.8 Å, 7 wt% − 17 Å, 1 wt% − 32.59 Å, and 7 wt% − 17.03 Å. Additionally, the energy transfer mechanism for luminescence quenching was determined as dipole-dipole (for Dy3+, Eu3+, and Tb3+) or dipole-quadrupole (for Sm3+) and the cross-relaxation process. GdAl 3 (BO 3) 4 samples obtained by doping with different RE3+ ions exhibit intense light emissions with different colors originating from different RE3+ ions under 349 nm excitation. When doped with different concentrations of RE3+ ions, the luminescence properties of the samples changed. The synthesized luminescence materials have potential applications in lighting and display technologies. [ABSTRACT FROM AUTHOR]

A series of strontium stannate (SrSnO 3) doped with Dy3+ ions at various wt % concentrations (1, 2, 3 and 5) were synthesized via hydrothermal reaction and analysed using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), environmental electron scanning microscope (ESEM), photoluminescence (PL) and, cathodoluminescence (CL). The XRD results confirmed that all samples were assigned to cubic perovskite-type SrSnO 3 structured with the P m 3 m ‾ space group. The PL emission spectrum of Dy3+ activated samples consisted of some characteristic peaks located at 481 nm, 572 nm, 660 nm and 753 nm, corresponding to (4F 9/2 → 6H 15/2 , blue), (4F 9/2 → 6H 13/2 , yellow), 660 nm (4F 9/2 → 6H 11/2 , red) and 753 nm (4F 9/2 → 6H 9/2 , red) transitions. The PL emission line intensity is gradually enhanced with an increase in doping concentration up to 3 wt %, followed by concentration quenching. The confinement effects of localized resonant energy transfer might cause higher concentration quenching. PL emission spectra were affected by the temperature range from 10 K to 300 K. PL emission anomalies at 270 K in SrSnO 3 :Dy3+ have been reported to be consistent with a structural phase transition at this temperature. This work confirms Singh et al.'s observation, revealing that SrSnO 3 has a phase transition at 270 K. [ABSTRACT FROM AUTHOR]

A series of Y 1-x Al 3 (BO 3) 4 :x Tb3+ (x = 0.5 to 7 wt%) phosphors synthesized by a gel combustion method have been systemically investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive spectroscopy (EDS), and photoluminescence (PL) as a function of temperature from 300 K to 10 K and 300 K–550 K. An XRD analysis confirms that the phosphors crystallized, and its crystal structure was analysed. The synthesized phosphor matches the XRD pattern provided in the ICSD File No 96-152-6006. The FTIR analysis indicates that nitrates and organic matter have been completely removed and the BO 3 groups are present. The broad PL band peaked at 420 nm with a shoulder circa 460 nm of YAl 3 (BO 3) 4 is associated with hydrous components which attached to the sample in environmental conditions after synthesis. The PL spectra of YAl 3 (BO 3):Tb3+ phosphors exhibit a bright and narrow green main emission peak at 543 nm corresponding to the 5D 4 →7F 5 transition under 359 nm excitation. The PL intensity increases with increasing Tb3+ ion concentration up to 5 wt %, followed by evidence for concentration quenching. There is a possibility that higher concentration quenching could be from confinement effects of localised resonant energy transfer. PL data revealed that activation energies for thermal quenching at 485 nm and 543 nm were found to be 0.659 and 0.092 eV, and 0.585 and 0.087 eV, respectively. [ABSTRACT FROM AUTHOR]

This study explores the structural and luminescent properties of terbium (Tb³⁺)-doped lanthanum aluminium borate (LaAl₂B₄O₁₀, abbreviated as LAB) phosphors, a novel host lattice for Tb³⁺ doping. LAB:Tb³⁺ phosphors, with varying dopant concentrations, were synthesized using a microwave-assisted combustion synthesis approach and characterized using X-ray diffraction (XRD), Rietveld refinement, and photoluminescence spectroscopy at both room and low temperatures. The structural analysis confirmed the hexagonal crystal structure of LAB and revealed successful incorporation of Tb³⁺ ions without altering the fundamental lattice. Luminescence studies demonstrated that the LAB:Tb³⁺ phosphors show strong green emission primarily attributed to the 5D 4 →7F 5 transition of Tb³⁺. The optimal doping concentration was determined to be 5 wt% Tb³⁺, which provided maximum luminescence efficiency. This concentration also allowed for a critical study of energy transfer mechanisms within the phosphor, revealing dipole-dipole interactions with a critical distance of 9.80 Å between Tb³⁺ ions. Additionally, the CIE chromaticity coordinates of LAB:0.05 Tb³⁺ were precisely determined to be (0.289, 0.4460), indicating the potential for high-quality green emission suitable for solid-state lighting and display technologies. This work not only demonstrates the potential of LAB:Tb3+ as a highly efficient green luminescent material, but also sheds light on the mechanisms responsible for energy transfer and concentration quenching. • Tb³⁺-doped LaAl₂B₄O₁₀ phosphors synthesized for green luminescence. • Photoluminescence properties studied at room and low temperatures. • Concentration quenching analysed for Tb³⁺ in LAB phosphors. • Rietveld analysis confirms hexagonal structure of LAB. • CIE chromaticity shows color shift with Tb³⁺ concentration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ce3+ and Tb3+ doped NaBaBO 3 were synthesized by combustion method. • Temperature-dependent behavior of Ce3+ and Tb3+ doped NaBaBO 3. • Identified optimal Ce3+, Tb3+ doping levels. • New insights into cross-relaxation mechanisms presented. • Dipole interactions key to emission intensity. This study explores the structural and temperature-dependent photoluminescence of Ce3+ and Tb3+ doped NaBaBO 3 phosphors, synthesized via combustion. Analysis of their crystal structures confirmed excellent alignment with the standard PDF#98–008-0110. Investigation into both room and low-temperature photoluminescence revealed that the dopants have a significant effect on emission spectra. Ce3+-doped samples exhibited excitation peaks at 275 nm and 358 nm, leading to a primary emission at 419 nm, with enhanced low-temperature emission suggesting reduced non-radiative processes. Tb3+-doped phosphors showed excitation from 250 to 377 nm and emissions from blue to deep red, including strong green emission at 550 nm due to 5D 4 →7F 5 transitions. Optimal doping was found at 1 mol% for Ce3+, while Tb3+ showed increased luminescence up to 3 mol%, with concentration quenching observed beyond these points. The study indicates dipole–dipole interactions dominate Ce3+ concentration quenching, whereas Tb3+ involves both electric dipole and quadrupole interactions. This analysis provides insights into enhancing luminescent efficiency and suggests NaBaBO 3 : x Ce3+,Tb3+ phosphors' potential in advancing white LED technology, highlighting their stable luminescent properties at low temperatures. [ABSTRACT FROM AUTHOR]

This study explores the structural and optical qualities of LaCa 4 O(BO 3) 3 (LACOB) phosphors doped with Eu3+, Dy3+, and Tb3+ using a microwave-assisted sol-gel technique. It uncovers oxygen-related luminescence defects in LACOB, highlighting emission peaks at 489 and 585 nm for Dy3+, a distinct sharp peak at 611 nm for Eu3+ in the red spectrum, and a notable green emission for Tb3+ due to specific transitions. The photoluminescence (PL) analysis indicates that luminescence is optimized through precise doping, leveraging dipole interactions, and localized resonant energy transfer, which are influenced by dopant concentration and spatial configuration. Temperature studies show emission intensity variations, particularly noticeable below 100 K for Tb3+ doped samples, demonstrating the nuanced balance between thermal quenching and luminescence efficiency. This temperature dependency, alongside the identified optimal doping conditions, underscores the potential of these materials for advanced photonic applications, offering insights into their thermal behavior and emission mechanisms under different conditions. [Display omitted] • Novel Eu3+, Tb3+, and Dy3+ Doped LaCa 4 O(BO 3) synthesized phosphors by microwave-assisted sol-gel technique. • Optimal Eu3+, Dy3+ and Tb3+ levels identified for peak emission. • Concentration quenching observed beyond optimal doping. • CIE analysis confirms consistent color output for tech applications. [ABSTRACT FROM AUTHOR]

Abstract: Charoite is a hydrous alkali calcium silicate mineral [K4NaCa7Ba0.75Mn0.2Fe0.05(Si6O15)2(Si2O7)Si4O9(OH)·3(H2O)] exhibiting an intense lilac colour related to Mn2+ and Fe3+ colour centres. These ions also contribute to a strong luminescence at ∼585 and 705nm. This work studies the thermal dependence of these luminescent centres by (i) thermoluminescence (TL) of pre-heated and pre-irradiated charoite aliquots, (ii) by time-resolved cathodoluminescence (TRS-CL) at room and cryogenic temperatures (RT and CT), (iii) by spatially resolved spectra CL under scanning electron microscopy (SRS–CL–SEM) and (iv) by ion beam spectra luminescence (IBL) with H+, H2 + and 4He+ ions at RT and LT. The main peak, ∼585nm, is linked to a transition 4T1,2 (G)→6A7(S) in Mn2+ ions in distorted six-fold coordination and the emission at ∼705nm with Fe2+→Fe3+ oxidation in Si4+ lattice sites. Less intense UV–blue emissions at 340 and 390nm show multi-order kinetic TL glow curves involving continuous processes of electron trapping and de-trapping along with an irreversible phase transition of charoite by de-hydroxylation and lattice shortening of Δa=0.219Å, Δb=0.182Å; Δc=0.739Å. The Si–O stressed lattice of charoite has non-bridging oxygen or silicon vacancy–hole centres, and Si–O bonding defects which seem to be responsible for the 340nm emission. Extrinsic defects such as the alkali (or hydrogen)—compensated [AlO4/M+] centres could be linked with the 390nm emission. Large variations in 585 and 705nm intensities are strongly temperature dependent, modifying local Fe–O and Mn–O bond distances, short-range-order luminescence centres being very resistant under the action of the heavy ion beam of 4He+. The SRS–CL demonstrates strong spatial heterogeneity in the luminescence of the charoite. [Copyright &y& Elsevier]

An investigation into the luminescent behavior of YCOB (Yttrium Calcium Oxyborate) doped with Eu3+ and Dy3+ ions, synthesized via the combustion method, is presented. The study, employing X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS) analyses, confirms the structural integrity and purity of the synthesized nanophosphors. An XRD pattern exhibiting distinct crystalline peaks indicates that the dopant ions were successfully integrated into the YCOB lattice. The photoluminescence (PL) response of YCOB with Eu3+ and Dy3+ ions is thoroughly examined, uncovering distinct excitation and emission spectra. In the case of Eu3+ doping, excitation spectra reveal a significant charge transfer (CT) band at 254 nm, indicative of electron transfer between oxygen and europium ions. This CT transition enhances our understanding of the excitation behavior, with the dominant and Laporte-forbidden 5D 0 → 7F 2 transition. Characteristic peaks at 345 nm in the excitation spectra efficiently stimulate YCOB:Dy3+ when Dy3+ is used as a dopant. The primary emission peak at 585 nm corresponds to the hypersensitive electric dipole transition 4F 9/2 –6H 13/2. Concentration quenching phenomena are observed, with a maximum Eu3+ concentration of 7 wt % attributed to the dipole-quadrupole interaction. Dy3+ doping, with a maximum concentration of 2 wt % primarily shows multipolar interactions, especially dipole-dipole interactions. The study extends to CIE chromaticity analysis, emphasizing Eu3+ doping's suitability for white light-emitting diode (WLED) applications and ensuring color stability. Conversely, varying Dy3+ concentrations do not yield consistent chromaticity coordinates. These findings have significant implications for the development of advanced phosphor materials across diverse applications, offering a roadmap for optimizing their optical performance. • Synthesized YCOB nanophosphors via combustion doping with Eu3+ and Dy3+. • Validated structural purity through XRD analysis of nanophosphors. • Identified optimal doping concentrations: 7 % for Eu3+ and 2 % for Dy3+. • Emphasized the suitability of Eu3+ doping for WLED applications, ensuring color stability. [ABSTRACT FROM AUTHOR]

Inorganic phosphors, known for their ability to capture energy from various sources and emit visible light, have become essential in the development of advanced lighting and display technologies. This study explores YCa 4 O(BO 3) 3 (YCOB) as a potential host material for phosphors, focusing on the luminescent properties of YCOB phosphors doped with Sm3+ ions. The successful integration of Sm3+ ions into the YCOB host lattice is confirmed through structural characterization using X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS). Photoluminescence (PL) studies reveal distinct emission spectra with Stark energy level splitting, indicating a cooperative effect between Y3+ and Sm3+ ions. Concentration quenching, mainly attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. Temperature-dependent PL measurements demonstrate thermal quenching at lower temperatures and increased emission intensity with higher laser power. Thermal quenching is explained by reduced lattice vibrations and electron-phonon interactions, leading to decreased radiative recombination of charge carriers. The CIE chromaticity data position the samples in the orange-red region, emitting vibrant orange-red light. This comprehensive investigation provides insights into the synthesis and luminescent properties of YCOB:Sm3+ phosphors, highlighting their potential applications in luminescent devices. • Explores the potential of Sm3+ ion-doped YCOB phosphors in luminescent materials. • Confirms successful integration of Sm3+ ions into the YCOB lattice. • Reveals cooperative interactions between Y3+ and Sm3+ ions. • Concentration quenching attributed to dipole-dipole interactions. • Discusses temperature and laser power effects on luminescence. [ABSTRACT FROM AUTHOR]

In the MgO–Al 2 O 3 system, magnesium aluminate spinel (MgAl 2 O 4) is a technologically significant compound due to its unique properties, including a high melting point, low thermal conductivity, excellent thermal shock resistance, chemical inertness, and robust mechanical strength. This compound has diverse applications in refractory materials, catalyst supports, moisture sensors, nuclear techniques, insulating materials, and even military applications. While rare-earth elements are commonly used as dopants in luminescent materials, limited research exists on doping of Tb3+ ions in magnesium aluminate. This study investigates the luminescence properties of Tb3+ doped synthesis magnesium aluminate materials, shedding light on this underexplored area. The combustion method is employed for synthesis, known for producing nano-sized powders with exceptional luminescent properties. Additionally, this study explores Sm3+ ion doping in magnesium aluminate materials and their luminescence properties. Using the combustion synthesis method, structural attributes of Tb3+−doped MgAl 2 O 4 nanophosphors are meticulously examined. Through X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, coupled with excitation and emission spectra, a comprehensive investigation of the luminescent provide behavior at room temperature is provided. The XRD data reveal Tb3+ doped MgAl 2 O 4 phosphors exhibit a single phase with face centred cubic structure belonging to the Fd3 m ‾ space group, consistent with the standard JCPDS files (No. 21–1152). Excitation and emission spectra offer valuable insights into the energy transitions within the Tb3+−doped MgAl 2 O 4 phosphors. Furthermore, the study explores the effects of varying Tb3+ ion concentrations on the luminescent properties, revealing an optimal doping concentration of 5 wt% Tb for maximizing emission intensity. Concentration quenching, primarily attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. In conclusion, this research enhances our understanding of rare-earth ion doping in luminescent materials and highlights the potential applications of Tb3+−doped MgAl 2 O 4 nanophosphors, which offer promise for various technological applications, including lighting and displays. • Investigation of Tb3+ ion-doped MgAl 2 O 4 phosphors for luminescent materials. • Successful integration of Tb3+ ions into the MgAl 2 O 4 lattice confirmed through structural characterization. • Concentration quenching phenomena, primarily linked to dipole-dipole (d-d) interactions. • Emphasizing the potential of MgAl 2 O 4 :Tb3+ phosphors in luminescent technology. [ABSTRACT FROM AUTHOR]

BeO, BeO:Al 1% , BeO:Ca 1% , and BeO:Al 1% ,Ca 0.1% ceramics were synthesized by the sol-gel method. The X-ray luminescence was studied, and broad emission peaks located at 230 nm (∼5.4 eV) and 300 nm (∼4.1 eV) were observed. We investigated thermoluminescence peaks contributing to optically stimulated luminescence (OSL) signals for the ceramics. The thermal quenching of the OSL signals was evaluated, and the quenching energies were estimated as between approximately 0.5 eV and approximately 0.7 eV. To check the feasibility for dosimetry purposes, the dose response, reusability, and dark storage fading of the OSL signals were investigated. The dose response was observed to be linear between 0.1 and 100 Gy. The minimum detectable doses of BeO, BeO:Al 1% , BeO:Ca 1% , and BeO:Al 1% ,Ca 0.1% were estimated as approximately 0.9 mGy, approximately 4 mGy, approximately 0.5 mGy, and approximately 0.5 mGy, respectively. Very good reusability was observed over ten cycles, with a maximum deviation of 2%. The results obtained from BeO:Al 1% ,Ca 0.1% could be useful for OSL dosimetry, particularly in medical applications. • The synthesis and doping of BeO powders using the sol-gel method. • The influence of the dopant on the structural and morphological properties of BeO ceramic pellets. • The effect of the dopant on optically stimulated luminescence dosimetric properties of BeO ceramic pellets. • Evaluation of thermal quenching energies for Al- and Ca-doped BeO ceramic pellets. • The relationship between thermoluminescence and optically stimulated luminescence signals from doped BeO ceramic pellets. [ABSTRACT FROM AUTHOR]

Abstract In present work, a series of Eu doped zinc borate, ZnB 2 O 4 , phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB 2 O 4 host lattice are studied for various beta doses ranging from 0.1 to 10 Gy. The high-temperature peak of Eu activated sample located at 192 °C exhibited a linear dose response in the range of 0.1–10 Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB 2 O 4 were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu3+ ions located at 576–710 nm assigned to the 5D 0 →7F J (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu3+ ions at 614 nm with transition 5D 0 →7F 2 was reached Eu3+ concentration of 5 mol%; quenching occurred at higher concentrations. Strong emission peak for Eu3+ ions at 614 nm with transition 5D 0 →7F 2 is observed. The CL experimental data indicate that ZnB 2 O 4 :Eu3+ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications. [ABSTRACT FROM AUTHOR]

A series of Eu3+-doped ZnGa 2 O 4 samples were synthesized via the urea-glycine combustion route. Powder X-ray diffraction (XRD) was used to investigate the crystallinity of the samples, energy dispersive spectroscopy (EDS) to explore the elemental composition, Fourier transform infrared (FTIR), to observe the vibrational modes of the samples, photoluminescence (PL) to determine the luminescence properties. The XRD data prove that the samples remain single cubic structure even at high concentrations of Eu³⁺, enabling the formation of a unique emission spectrum. The active ion concentration was varied to examine the influence of concentration on luminescent properties. This study revealed a 5D 0 →7F 4 transition located at 700 nm with unusual intensity that has not been documented in the literature, which suggests that the active ion concentration can influence the luminescent characteristics of the phosphors. The increasing Eu3+ content increases the number of Eu3+ ions in ZnGa 2 O 4 host lattice, which enhances the luminescence efficiency of the phosphor. However, beyond a certain level of Eu3+content (i.e., 3 wt% Eu3+), the number of Eu3+ ions becomes excessive, resulting in a reduction in luminescence efficiency due to concentration quenching. The dipole dipole interaction is elucidated to play a prominent role in the mechanism of Eu3+ quenching in the ZnGa 2 O 4. An assessment of color coordinates based on emission spectra reveals that the coordinates shift from blue to the white light region, and then to red as Eu3+ content increases. This suggests that there is a substantial relationship between the Eu3+ concentration and the measured color coordinates. [Display omitted] • ZnGa 2 O 4 phosphor was produced by gel combustion method. • Luminescence characteristic of Eu doped ZnGa 2 O 4. • Unusual intense red emission at 701 nm. • Discussion of concentration quenching mechanism. [ABSTRACT FROM AUTHOR]

A new lithium tetraborate (Li 2 B 4 O 7 or abbreviated as LTB) material was produced by adding various concentrations of Ag impurities to allow better luminescent properties using the solution combustion synthesis (SCS) method. The formation of single phase LTB was confirmed using X-ray Diffraction (XRD) data and Scanning Electron Microscopy (SEM) analysis indicated the existence of a tetragonal crystalline domain. Two broad band emissions located at ∼ 272 nm (near UV region) and 526 nm (green region) were observed from room temperature photoluminescence (PL) under 205 nm excitation The synthesized material consisted of polycrystalline LTB with 1 wt% Ag (abbreviated herein as LTB:Ag) exhibits considerable thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) which is several times more sensitive to beta radiation than the other concentrations attempted. It was determined that the OSL signal has been a collection of three component signals. A step-preheating procedure to investigate the depth of the trapping centers associated with the OSL signal was carried out. We suggest that the TL peak at 200 °C mainly contributes to the OSL signal. It was observed that the total OSL area shows a linear dose response for beta doses ranging from 1 to 100 Gy. The minimum detectable dose (MDD) value was found to be around 3 mGy using the total OSL area. Under optimum conditions (irradiation with beta-rays), the reproducibility of total OSL area was determined with a −3% deviation at the end of the 9th irradiation-blue light stimulation-readout cycle. The dark storage stability of the total OSL signals was investigated and fading of the total OSL area was found to be approximately 25% after one week. The trap depth corresponding to the OSL signal was found to be 0.99 eV and 0.94 eV using various heating rate and isothermal annealing methods, respectively. Finally, silver doped lithium tetraborate is shown to have promise as an optically stimulated luminescent dosimeter, particularly in medical and personal applications. [ABSTRACT FROM AUTHOR]

Abstracts Ce doped Yttrium aluminate modified by replacing different molar part of aluminium or gallium (Y 3 Al 5−x Ga x O 12 ) and Yttrium silicate phosphors activated with Ce and Tb (Y 2 SiO 5 :Ce 3+ ,Tb 3+ ) were synthesized by solid state reaction and a gel combustion method, respectively. X-ray diffraction and Scanning electron microscope (SEM) techniques are used to identify their structures and morphologies. Luminescence characteristics are measured and spectroscopic data confirm that Y 2 SiO 5 :Ce 3+ , Tb 3+ phosphors can be effectively excited upon UV excitation light and X-ray irradiation, resulting in intense blue and green emissions, respectively. This energy transfer takes place by means of a non-radiative process inside Ce 3+ -Tb 3+ clusters formed in the host matrix. Tb 3+ doped Y 2 SiO 5 yields both blue emission 5 D 3 → 7 F j ( j = 3,4,5,6) and green emission 5 D 4 → 7 F J ( J = 3,4,5,6) of Tb 3+ . Y 3 Al 5−x Ga x O 12 :Ce 3+ phosphors exhibit a broad blue emission band originating from allowed 5d-4f transition of the Ce 3+ ions under different excitation sources but the broad emission band shifts with increasing of Ga 3+ content. This work presents a quantitative understanding of host material's on dopant's luminescence properties and thereby provides an optimization guideline, which is extremely demanding for the development of new luminescent materials. [ABSTRACT FROM AUTHOR]

A series of novel apatite-based Ca 2 Y 8 (SiO 4 ) 6 O 2 phosphors doped with Ce 3+ and Tb 3+ were synthesized by a solid-state reaction method at different calcination temperatures and times. The comparative results of thermal analysis (TG-DTA), FTIR, X-ray diffraction (XRD) and environmental scanning electron microscope (ESEM) reveal that the firing temperature for Ca 2 Y 8 (SiO 4 ) 6 O 2 :Ce 3+ , Tb 3+ was optimized to be 1200 °C. The systematic studies on the influences of thermal treatment conditions on photoluminescence (PL) and cathodoluminescence (CL) properties were also reported. The excitation spectra of Ca 2 Y 8 (SiO 4 ) 6 O 2 :Ce 3+ , Tb 3+ exhibited one strong excitation band at 325 nm. The PL and CL results indicated that the violet-blue emission intensities about 400 nm from the Ce 3+ and efficient green emission at 544 nm from Tb 3+ were highly dependent on the calcination conditions. [ABSTRACT FROM AUTHOR]

• A series of Dy3+ doped and Eu3+ co-doped GAB phosphors were synthesized. • The phosphor GAB doped with Dy3+ has the optimal luminescence performance. • Direct transfer of energy from Dy3+ to Eu3+ are observed. • The effects of energy transfer on luminescence lifetime of the ions were discussed. • Concentration quenching and cross-relaxation between adjacent RE were discussed. The synthesis of GdAl 3 (BO 3) 4 phosphors incorporated with activators of Dy3+ and Dy3+/ Eu3+was successful and achieved through the gel combustion method. Powder X-ray diffraction (XRD) was employed to identify phase purity and the effects of dopant concentration on the crystallographic structure. The results of Photoluminescence (PL) measurements revealed that the intensity and lifetime of luminescence properties varied depending on the concentrations of Dy3+ and Eu3+ ions. The dependence of luminescence intensity on doping concentration is investigated with respect to the energy transfer process between Eu3+ and Dy3+ ions. A decrease in luminescence lifetime occurs with increasing concentrations of Eu3+ co-doping. The energy transfer was also investigated using decay curve analysis. The co-doping of Eu3+ significantly boosts the energy transfer efficiency from 26% to 84%. These findings make GdAl 3 (BO 3) 4 : Dy3+, Eu3+ phosphors an ideal choice for LED applications in solid state lighting and displays. [Display omitted] [ABSTRACT FROM AUTHOR]

Manganese (Mn) doping of ZnS phosphors was achieved by precipitation method using different ultrasound (US) maturation times. The structural and luminescence properties of the samples were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), and cathodoluminescence (CL). The real amount of manganese incorporated in ZnS lattice was calculated based on ICP-OES results. According with XRD patterns, the phase structure of ZnS:Mn samples is cubic. EDS spectra reveal deviations of the Mn dopant concentration from the target composition. Both 300 K PL and CL emission spectra of the Mn doped ZnS phosphors display intense orange emission at 590 and 600 nm, respectively, which is characteristic emission of Mn ion corresponding to a 4 T 1 → 6 A 1 transition. Both PL and CL spectra confirmed manganese is substitutionally incorporated into the ZnS host as Mn 2+ . However, it is suggested that the origin of broad blue emission around 400 nm appeared in CL is due to the radiative recombination at deep level defect states in the ZnS. The ultrasound treatment at first enhances the luminescent intensity by ∼3 times in comparison with samples prepared by classical way. This study gives rise to an optimization guideline, which is extremely demanded for the development of new luminescent materials. [ABSTRACT FROM AUTHOR]

Several ZnB 2 O 4 powder samples having dopants concentrations of 0.1, 0.01, 0.04 wt% Ce and La were prepared using the nitric acid method via the starting oxides. Several complementary methods such as powder X-ray diffraction (XRD), thermal analyses environmental scanning electron microscopy (ESEM), Radioluminescence (RL) and Cathodoluminescence (CL) techniques were used. Unique luminescence properties of Ce doped ZnB 2 O 4 powder samples are reported for the first time. A new luminescence bands appearing in red part of the spectrum and having all the characteristics of Ce 3+ were obtained from RL results. Changing the Ce and La concentration of 0.01–0.1 wt% leads to an increase in RL and CL intensities of Ce 3+ and La 3+ ions and also CL emission spectra of ZnB 2 O 4 show gradual shift towards longer wavelength. When we compare the luminescence intensity of the samples it is seen that Ce doped ZnB 2 O 4 has the highest intense whereas La doped ZnB 2 O 4 has the lowest one. However, emission spectra of both Ce and La doped samples kept unchanged. [ABSTRACT FROM AUTHOR]

We have synthesized powder samples of Dy 3+ doped zinc borates by nitric acid method. X-ray diffraction (XRD) and environmental scanning electron microscope (ESEM) techniques were utilized to examine the structure and morphological observation of the samples. Luminescence characteristics of the samples were investigated using room temperature (RT) cathodoluminescence (CL) and radioluminescence (RL) measurements under excitation with electron beam and X-rays, respectively. The presence of small amounts of Dy 3+ incorporated in the host lattice does not affect the structure of the prepared samples remarkably. The CL and RL spectra showed the characteristic emissions of Dy 3+ (magnetic dipole transition of 4 F 9/2 → 6 H 11/2 Blue; forced electric dipole transition of 4 F 9/2 → 6 H 13/2 Yellow; 4 F 9/2 → 6 H 11/2 Red; 4 F 9/2 →( 6 H 9/2 + 6 H 11/2 ) infrared). Thermoluminescence (TL) method was also conducted to determine the effects of various concentrations of Dy 3+ on the TL properties of ZnB 2 O 4 . The TL glow peak of beta irradiated ZnB 2 O 4 :Dy 3+ phosphors is a well-defined and centered at around 96 °C with a constant heating rate of 2 °C/s. Initial rise method was employed to observed main TL glow curve for determining the activation energy ( E a ) and the frequency factor ( s ). [ABSTRACT FROM AUTHOR]

In this study, manganese (Mn) doped Calcium Tetraborate (CaB 4 O 7 ) samples were prepared by the wet chemical method. Under beta irradiated, CaB 4 O 7 :Mn showed thermally stimulated luminescence (TSL) glow peaks at approximately 85 °C and 220 °C with a heating rate of 5 °C/s. Peak shape (PS) and various heating rates (VHR) methods were applied for determining the trap parameters such as order of kinetic (b), activation energy (E) and frequency factor (s). The results indicate that the main dosimetric peak of CaB 4 O 7 :Mn follows the second-order kinetic model. The thermal fading ratio of the material is around 15% at the end of one month period of storage. The results of the TL studies carried out on the CaB 4 O 7 :Mn dosimeter revealed that it has high sensitivity, which makes it very valuable in various dosimetric applications like space, medical, personal dosimetry and dating. Radioluminescence (RL) of CaB 4 O 7 :Mn was also studied. It is shown that the RL spectrum contains a wide band centered at 530 nm assigned to Mn 2+ ion emission. A broad band emission feature peaked at 350 nm assigned to the non-bridging oxygen hole center (NBOHC) is also discussed and a model is proposed to explain this broad band feature. [ABSTRACT FROM AUTHOR]

Here, we report our results referring to the preparation of Ce doped Y 2.22 MgGa 2 Al 2 SiO 12 , Y 1.93 MgAl 4 SiO 12 and Y 2.22 Gd 0.75 Ga 2 Al 3 O 12 using solid state reaction at high temperature. Several complementary methods (i.e. powder x-ray diffraction (XRPD), energy dispersive analysis of X-rays (EDX), scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR)) were studied to examine the effects of the synthesis procedure on the morphology and structure. XRD analyses revealed that all compounds include yttrium aluminate phase with garnet structure. Cathodoluminescence (CL), radioluminescence (RL) and photoluminescence (PL) measurements were carried out for clarification of relationship between host lattice defects and the spectral luminescence emissions. Luminescence emission of phosphors is peaked at 530 nm assigned to 5d-4f transitions of the dopant Ce 3+ ions with a broad emission band in 400–700 nm range. Under electron irradiation, the emission spectrum of Ce doped (YGd) 3 Ga 2 Al 3 O 12 is well defined and has a characteristic fairly narrow and sharp emission band peaking at 312 nm and 624 nm corresponding to transition of 6 P 7/2 → 8 S 7/2 and 6 G J → 6 P J (Gd 3+ ), respectively. We suggest some of phosphors might be excellent phototherapy phosphor materials under electron excitation. [ABSTRACT FROM AUTHOR]

Herein, we primarily focus on luminescence spectrum measurements of various types of green emitting yttrium aluminate phosphors modified with gallium (Y 3 Al 5-x Ga x O 12 ) synthesised by solid state reaction. The luminescent emission of samples depends on sample temperature and excitation radiation such as incident X-ray, electron and laser beam. Here, we measured radioluminescence (RL), cathodoluminescence (CL), photoluminescence (PL) along with XRD in order to clarify relationship between lattice defects and the spectral luminescence emissions. The RL and CL spectra of YAG:Ce exhibit an emission band ranging from 300 to 450 nm related to Y Al antisite defects. The broad emission band of garnet phosphors is shifted from 526 nm to 498 nm with increasing of Ga 3+ content, while full width at half maximum (FWHM) of the band tends to be greater than the width of unmodified YAG:Ce garnet. Deconvolution of the spectrum reveals that three emission bands centred at 139, 234 and 294 °C occur in aluminate host garnets. [ABSTRACT FROM AUTHOR]

Cerium and terbium activated white emitting yttrium silicate phosphors (Y 2−x − y Ce x Tb y SiO 5 ) having average size between 96 and 123 nm were synthesised by a gel-combustion, and their phase and crystal structures, morphologies and ultraviolet (UV)-visible spectroscopic properties were studied. All rare earth doped yttrium silicate (YSO) phosphors are well crystallized powders containing only monoclinic X2-Y 2 SiO 5 phase. No significant changes in the cell parameters were observed with increasing of Tb amount as ionic radii of Tb 3+ (0.923 Å) and Y 3+ (0.9 Å) have almost the same. Under different excitations, YSO:Ce 3+ exhibits blue emission due to the 5d–4f transitions of Ce 3+ ions. The series of emission states at different wavelengths of YSO:Tb 3+ associated to f – f transition of Tb 3+ ion were detected from luminescence measurements. The emission observed at 544 nm (green) corresponding to 5 D 4 → 7 F 5 of Tb 3+ is strongest one. Incorporation of variable amounts of Tb 3+ in the YSO host lattice determines the modification of emission colour from blue through light blue and eventually to bluish green. A possible energy transfer mechanism taking place from Ce 3+ to Tb 3+ was also discussed in terms of excitation and emission spectra. [ABSTRACT FROM AUTHOR]

Structural and optical properties of erbium- and manganese-doped strontium aluminates (SrAl 2 O 4 ) phosphor materials synthesized by a solid state reaction were investigated. The samples presented the fundamental optical transitions due to Er 3+ and Mn 2+ which are typical features of the well-diluted doping process. A significant enhancement of the Er 3+ optical emission band at 1530 nm was observed when the matrix is co-doped with Mn. Photoluminescence intensity under ultraviolet excitation was three times larger as compared to samples without Mn content. A model of energy transfer mechanism from Mn 2+ to Er 3+ ions due to optical energy matching is proposed to explain the experimental results. This result, presented first time, can be applied as useful tool for developments in optical communications. [ABSTRACT FROM AUTHOR]

Novel stannate phosphor, orthorhombic CaSnO 3 phosphors doped with Er 3+ , Nd 3+ and Sm 3+ have been synthesized by a conventional solid-state method under N 2 +H 2 gas flow. Visible and near-infrared photoluminescence (PL) properties were investigated as function of laser power and temperature. It was observed that all dopant ions are well incorporated in CaSnO 3 and are responsible for the optical emission in the temperature range of 10–300 K. PL peaks at 490, 546, 656, 696, 894, 1065, and 1344 nm were observed for the CaSnO 3 :Nd 3+ phosphor and associated to f – f transition of Nd 3+ ion. Emissions at 564, 600–607, 646–656 and 714 nm were detected for the CaSnO 3 :Sm 3+ . The strongest one, observed at 600 nm, was associated to 4 G 5/2 → 6 H 7/2 of Sm 3 . Emission lines at 528, 548, 662 at 852 nm were also seen for CaSnO 3 :Er 3+ and correspond to Er 3+ intra-4 f n shell transitions. In addition, at low temperatures, a stark splitting of the 4 f electron energy levels of the Er 3+ ions were observed in infrared region (1520–1558 nm) and assigned to the transition between the 4 I 13/2 state and the 4 I 15/2 state. Finally, our results show that the rare earth doped CaSnO 3 has remarkable potential for applications as optical material since it exhibits efficient and sharp emissions due to rare earth ions. [ABSTRACT FROM AUTHOR]

The present study describes cathodoluminescence (CL) properties of CaSnO 3 phosphors doped with Eu 3+ , Tb 3+ and Dy 3+ synthesized by a solid-state method. X-ray diffraction (XRD) patterns confirm that CaSnO 3 sintered at 1200 °C exhibits orthorhombic structure. The evidence and rationale for two strong broad emission bands appeared at 360 and 780 nm for undoped CaSnO 3 are presented. The CL measurements exhibit that the 4 f –4 f emissions from 5 D 4 → 7 F 6 (490 nm), 5 D 4 → 7 F 5 (544 nm), 5 D 4 → 7 F 4 (586 nm) and 5 D 4 → 7 F 3 (622 nm), assigned to possible transitions of Tb 3+ ions are seen. The strongest one, observed at 544 nm, due to its probability of both magnetic and electric transitions make the sample emission green. Emissions at 480, 574, 662 and 755 nm were detected for the CaSnO 3 :Dy 3+ and attributed to the transitions from the 4 F 9/2 to various energy levels 6 H 15/2 , 6 H 13/2 , 6 H 11/2 and 6 H 9/2 + 6 F 11/2 of Dy 3+ , respectively. CL spectra of Eu doped CaSnO 3 reveal that there is a strong emission peak appeared at 615 nm due to the electric dipole transition 5 D 0 → 7 F 2 (red). Finally, our results show that the rare earth doped CaSnO 3 have remarkable potential for applications as optical materials since it exhibits efficient and sharp emission due to rare earth ions. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new stannate phosphor, SrSnO3:Tb3+ was synthesized by solid state reaction method. [•] The role of Tb3+ doped into SrSnO3 was discussed. [•] A structural phase transition in SrSnO3:Tb3+ at ∼270K was suggested. [ABSTRACT FROM AUTHOR]

BaSiF 6 phosphor was synthesized by a gel combustion method. The crystalline size was found to be 54.17 ± 4.36 nm using Williamson-Hall (W–H) approximation. The TL data collected by means of a combination of a commercial BG39 and HC575/25 filters was studied to evaluate basic kinetic parameters. Three TL glow peaks of BaSiF 6 phosphors are centered at around 84, 190 and 322 °C. T m -T stop , various heating rate (VHR) and computerized glow-curve deconvolution (CGCD) method were utilized to analyse collected data. Our findings indicate that luminescence process in scrutinized material may obey second order kinetics. The TL dose response of the TL glow peaks exhibits a linear characteristic up to 100 Gy. Deconvolution of the glow curve reveals that the number of the component TL glow peaks in the complex glow curve is composed of well-isolated six overlapping glow peaks. The FOM value is 2.32. [Display omitted] • Gel combustion method of BaSiF 6 phosphor. • Williamson-Hall techniques were adopted to investigate the crystalline size. • TL kinetic parameters of BaSiF6 phosphor using IR, VHR and CGCD methods were estimated. [ABSTRACT FROM AUTHOR]

Abstract: Natural blue-green beryl from Turkey has been investigated using scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and Cathodoluminescence (CL). Beryl has the chemical formula Be3Al2Si6O18 and is hexagonal with space group P6/mcc. Chemical analyses of the beryl sample utilised inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for major oxides and trace elements. It shows that the beryl sample is rich in Cs (531ppm) and contains low concentrations of transition-metal ions, in total 2.29wt.% Fe, 269ppm Mn, V<5ppm and Cr 20ppm. Ideas on the origin of the green colour of this mineral are presented. The CL spectrum of the bulk sample display intense broad band emission from ∼360 to ∼800nm. [Copyright &y& Elsevier]

Abstract: Chemical analyses performed on chrysoprase from Turkey have shown many trace elements as well as rare earth impurities. Quantitative chemical analyses of inclusions in minerals can improve our understanding of the chemistry of surface. The environmental scanning electron microscope (ESEM) with an attached X-ray energy dispersive system (EDS) is capable of producing rapid and accurate major element chemical analyses of individual inclusions in crystals larger than about 30μm in diameter. The samples were examined with lifetime-resolved and spatially-resolved cathodoluminescence (CL), and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Spatially resolved CL results at room temperature were recorded for two different areas. Bulk area displays with low CL emission and pores contain iron phases such as chromite, hematite and anatase which cause the green color. For the raw data in the lifetime resolved CL spectrum, at least three broad emission bands were detected in a yellow band of the highest intensity at about 550nm, a weaker orange band at about 650nm, and a red band at 720nm. It is assumed that there are links between the CL emissions and the presence of some transition metal and REE elements, but it is obvious that all trace elements do not play a direct role. Micro-Raman measurements were performed on chrysoprase and these showed a characteristic intensive Raman band peaked at 464cm−1 which can be inferred to ν2 doubly symmetric bending mode of [SiO4/M] centers. Raman spectrum of all inclusions found in the material are also given and discussed in detail. [Copyright &y& Elsevier]