Effect of Dopant Concentration on Luminescence Properties of Na3Ca2(SO4)3F: RE (RE = Eu3+, Dy3+) Phosphor for Solid-State Lighting.

A fluoride material phosphor doped with rare earth ions Eu3+ and Dy3+ was studied for its photoluminescence (PL) properties. The material was synthesized using a combustion method and characterized using X-ray diffraction (XRD) and PL techniques. The Na3Ca2(SO4)3F: Eu3+ phosphor exhibits two distinct peaks at 593 nm (orange) and 615 nm (red) at an excitation wavelength of 395 nm. The PL excitation spectrum of the Na3Ca2(SO4)3F: Dy3+ phosphor showed series of peaks, corresponding to the 4f → 4f transitions of Dy3+ ions. Under 350-nm excitation, the PL emission spectrum revealed two prominent bands one at 483 nm (blue region) due to the 4F9/2 → 6H15/2 transition, and another at 573 nm (yellow region) resulting from the 4F9/2 → 6H13/2 transition. These blue and yellow emissions suggest potential applications in solid-state lighting, particularly for mercury-free excitation sources. Rare earth-doped Eu3+/Dy3+ materials exhibit highly efficient PL properties, making them suitable candidates for white light-emitting diodes (LEDs) or other solid-state lighting phosphors.

Intense Blue Emission Energy Transfer Analysis in Ce3+-Eu2+ Activated NaBa(PO3)3 Phosphors for Blue LEDs and Plant Growth Technologies.

Phosphites are being recognized as the new emerging candidates for luminescence in the modern era. In the proposed research article, Ce3+/Eu2+ co-activated NaBa(PO3)3 phosphite phosphors synthesized utilizing sol-gel technique. Through the use of XRD and Rietveld refinement, the phase identity and crystal structure of produced phosphor are examined. SEM is employed to analyze the morphology and elemental composition of the prepared sample. The sample shows blue emission enhancement in the phosphor on energy transfer with the Ce3+ ion by 6 times. This highly instance blue emitting phosphor has color purity of 98.49%. These all results confirm that the prepared phosphor is potential candidate for WLEDs, display applications and blue emitting phosphor for plant cultivation applications.

Dosimetric evaluation and gradient analysis of various MLC leaf-width effects in external beam radiation therapy: TrueBeam Vs Halcyon.

INTRODUCTION: This study investigates dosimetric influence and gradient-analysis of leaf-width of various Multi-leaf-collimators (MLC) from Truebeam and Halcyon linear accelerators. METHODS: The leaf-width effects of Millennium120 and HD120MLC from Truebeam and SX1 and SX2 from Halcyon were studied using virtual phantom in Eclipse16.1.2 TPS. Target structures consist of bore and wave cylinders of equally spaced projected Planning target volume (PTV) of diameters ranging from 1-to-5 cm and 20 cm length. Treatment plans for all PTVs, and four different MLCs configurations from both machines were created utilizing 6MVFFF beam to deliver dose of 50Gy/25# using IMRT and VMAT. Plans were evaluated using plan quality indices including dose conformity, homogeneity, gradient radius, and Monitor-unit (MU). Also, dose gradients were analyzed by estimating distinct integral volume VD% and paired-t-tests were performed to evaluate statistical differences. RESULTS: All the plan satisfied the minimum criteria of D95 %≥prescription dose and V107 %≤2cc. Mean conformity and homogeneity indices for SX1MLC(CI = 0.680,HI = 0.022) were found significantly higher and lower than SX2(CI = 0.746,HI = 0.016), Millennium120 (CI = 0.739,HI = 0.012), and HD120MLC(CI = 0.745,HI = 0.017), respectively. However, CI and HI for SX2, Millennium120, and HD120MLC found comparable. Gradient radius enclosing 50 % of isodose observed maximum and minimum for SX1 and HD120MLC, respectively. Plan MUs for Truebeam MLCs were found approximately 25 % higher than Halcyon MLCs. Dose distribution generated using SX2 and Millennium120 found comparable, however p ≤ 0.05 ascertained substantial differences among SX1, Millennium120, and HD120MLC. CONCLUSION: MLC leaf-width influences intensity-modulation and significantly alters dosimetric outcome depending on the magnitude of the leaf-width. HD120MLC does not show much significant advantages over SX2 and Millennium120 except gradient control. IMPLICATIONS FOR PRACTICE: Halcyon SX1MLC produces least effective plan compared to all other MLC types. However, SX2 and Millennium120 can produce plans of comparable quality except plan MUs difference.

Highly Efficient Far-Red Emitting Mg21Ca4Na4(PO4)18: Ce3+, Eu3+ Luminescent Glasses: A Novel Approach Towards Plant Cultivation Technologies.

One of the exciting developments in contemporary luminescence research is the development of rare earth triggered luminescent glasses, which are a type of lanthanide activated luminous material. For the first time, Ce3+, Eu3+ activated/co-activated Mg21Ca4Na4(PO4)18 orthophosphate glasses have been synthesized using the proposed work's melt quenching technique. The proposed glass sample's XRD pattern has an amorphous character, although its most prominent peak matches data from the Mg21Ca4Na4(PO4)18 standard ICSD database. FT-IR analysis was used to analyze the proposed glass sample's vibrational characteristics. Co-activated Mg21Ca4Na4(PO4)18 glass exhibits large emission peaks under UV excitations that cover the far red area during a photoluminescence examination. These outcomes demonstrate the proposed sample's value in applications such as WLEDs and plant cultivation.

Photoluminescence properties of Pb5(PO4)3Br:RE (RE = Dy3+, Eu3+ and Tb3+) phosphor synthesised using solid-state method.

This study describes the luminous properties of Pb5(PO4)3Br doped with RE3+ (RE = Dy3+, Eu3+ and Tb3+) synthesised using the solid-state method. The synthesised phosphor was characterised using Fourier-transform infrared, X-ray diffraction, scanning electron microscopy and photoluminescence measurements. Dy3+-doped Pb5(PO4)3Br phosphor exhibited blue and yellow emissions at 480 and 573 nm, respectively, on excitation at 388 nm. Eu3+-doped Pb5(PO4)3Br phosphor exhibited orange and red emissions at 591 and 614 nm, respectively, on excitation at λex = 396 nm. Pb5(PO4)3Br:Tb3+ phosphor exhibited the strongest green emission at 547 nm on excitation at λex = 380 nm. Additionally, the effect of the concentration of rare-earth ions on the emission intensity of Pb5(PO4)3Br:RE3+ (RE3+ = Dy3+, Eu3+ and Tb3+) phosphors was investigated.

Dosimetric Evaluation of Radiation Treatment Planning for Simultaneous Integrated Boost Technique Using Monte Carlo Simulation.

Monte Carlo (MC) techniques have been recognized as the gold standard for the simulation of radiation transport in radiotherapy. The aim of the study is to perform dosimetric evaluation of Simultaneous Integrated Boost (SIB) radiation treatment planning using MC simulation approach. The geometrical source modeling and simulation of 6 MV Flattening Filter Free (FFF)beam from TrueBeam linear accelerator have been carried out to simulate Volumetric Modulated Arc Therapy (VMAT) plans using MC simulation software PRIMO. All the SIB plans have been generated using VMAT techniques for patients with locally advanced postoperative head-and-neck squamous cell carcinoma in Eclipse Treatment Planning System (TPS) retrospectively. TPS plans have been compared against their respective MC-simulated plans in PRIMO. The quality assessments of plans have been performed using several dose volume parameters, plan quality indices, and methods of gamma analysis. Dmean, D50%, and D2% received by planning target volume (PTV), PTV60, and PTV52 have been found significantly lower in TPS-generated plans compared to MC-simulated plans. D100%, D98%, and D95% received by PTV60 exhibit good agreement. However, PTV52 shows a significant deviation between TPS and MC plans. The mean organ-at-risk doses have been found significantly lower in TPS plans compared to MC plans. TPS and MC plans have been found in close agreement within gamma acceptance criteria of 3% Dose Difference (DD) and 3 mm Distance to Agreement (DTA). Dose distributions computed using MC simulation techniques are reliable, accurate, and consistent with analytical anisotropic algorithm. Plan quality indices have been found slightly compromised in MC-simulated plans compared with TPS-generated plans appeared to be a true representation of real dose distribution obtained from MC simulation technique. Validation using MC simulation approach provides an independent secondary check for ensuring accuracy of TPS-generated plan.

Tailored efficient energy transfer Tb3+, Eu3+ activated/co-activated LiAl(PO3)4 phosphor by substitution of alkali metals: the effect of charge compensation.

Phosphites are the new emerging candidates in the field of luminescence in the modern era. In the present investigation, Tb3+/Eu3+ activated/co-activated LiAl(PO3)4 phosphor was prepared by a wet chemical method, and the effect of R+ (Na+, K+) ions on photoluminescence (PL) properties of these phosphors are investigated. Phase identification and crystal structure of the prepared phosphor were determined using XRD and Rietveld refinement, respectively. Morphological study and elemental analysis of the proposed phosphor with elemental analysis of the sample were performed using SEM and EDS. The PL properties of the proposed phosphor showed three simultaneous emission peaks in the visible range, giving color-tunable emission. The charge compensation of Na+ and K+ ions make a significant impact on the PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors. The PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors was significantly enhanced by factors 1.2 and 1.4 when Na+ and K+ charge compensators, respectively, were introduced. To manifest the charge compensation effect of alkali metals the optimum intense sample in the co-doped sample was used. These results indicate the potential candidacy of the studied phosphor for further improvement in PL properties for application in solid-state lighting.

Luminescence Thermometry Based on the Upconversion Luminescence from the Stark Sublevels of BaY2F8:Yb3+, Tm3+ Phosphor.

Visible and near-infrared (NIR) upconversion luminescence (UCL) emissions originating from the BaY2F8: Yb3+, Tm3+ systems were investigated under a laser excitation at 980 nm. The BaY2F8:20 mol% Yb3+, x mol% Tm3+ and BaY2F8: y mol% Yb3+, 0.5 mol% Tm3+ phosphors showed prominent UCL at 800 and 810 nm. The optimized doping concentrations of Yb3+ and Tm3+ in the BaY2F8 host matrix were evaluated, their spectroscopic properties were determined, and studies on their temperature-dependent behaviour were carried out. The temperature-sensing properties were studied by generating the fluorescence intensity ratio (FIR) of the UCL peaks originating from the thermally-coupled energy levels of the Tm3+ ions. The Stark sublevels of 1G4 level of Tm3+ ions were utilized to estimate the temperature-sensing abilities of the phosphor.

Optical transitions and radiative properties of green emitting Ho3+:YVO4 phosphor.

The Ho3+-doped YVO4 phosphors were successfully prepared via a sol-gel process in which citric acid was used as a chelating agent. X-ray diffraction (XRD) confirmed the effective inclusion of Ho3+ ions into the host matrix with the formation of single phase YVO4. The surface morphology was observed using SEM, the results of which showed a grain growth propensity and the agglomeration of prepared phosphors. The V-O (VO4 3-) vibration mode was analyzed through Fourier transform infrared (FTIR) spectra. The spectroscopic properties were reported through UV-vis-NIR diffuse reflectance and photoluminescence (PL) spectra. The Judd-Ofelt (J-O) intensity parameters Ω 2 = 0.03 × 10-20 cm2, Ω 4 = 0.22 × 10-20 cm2, and Ω 6 = 0.23 × 10-20 cm2 obtained for the Y0.97VO4:0.03Ho3+ phosphors were used to obtain the total transition probabilities (A T), radiative lifetimes (τ rad) and branching ratios (ß) for the certain transitions of Ho3+ ions. Under 310 nm UV excitation, the visible emission spectra were measured, and an intense emission was observed around 541 nm (green region) for all the samples. The emission cross-section σ P(λ) was 3.22 × 10-21 cm2 and the branching ratio (ß) was 0.816; these were investigated to capture the optimal concentration of the Y0.97VO4:0.03Ho3+ phosphor. The estimated color coordinates were observed in the green region of CIE diagram. Ultimately, the superior properties (σ P(λ), ß, and color purity) of Y0.97VO4:0.03Ho3+ phosphor may make it suitable for green emitting devices.

Retraction: A study on the luminescence properties of gamma-ray-irradiated white light emitting Ca2Al2SiO7:Dy3+ phosphors fabricated using a combustion-assisted method.

[This retracts the article DOI: 10.1039/C6RA04913C.].

Evaluation of the dosimetric influence of interfractional 6D setup error in hypofractionated prostate cancer treated with IMRT and VMAT using daily kV-CBCT.

INTRODUCTION: Prostate cancer is one of the most common malignant tumors in men and is usually treated with advanced intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Significant uncorrected interfractional 6-Dimensional setup errors could impact the delivered dose. The aim of this study was to assess the dosimetric impact of 6D interfractional setup errors in hypofractionated prostate cancer using daily kilovoltage cone-beam computed tomography (kV-CBCT). METHODS: This retrospective study comprised twenty prostate cancer patients treated with hypofractionated IMRT (8) and VMAT (12) with daily kV-CBCT image guidance. Interfraction 6D setup errors along lateral, longitudinal, vertical, pitch, roll, and yaw axes were evaluated for 400 CBCTs. For targets and organs at risk (OARs), the dosimetric impact of rotational error (RError), translational error (TError), and translational plus rotational error (T+RError) were evaluated on kV-CBCT images. RESULTS: The single fraction maximum TError ranged from 12-20 mm, and the RError ranged from 2.80-3.00. The maximum mean absolute dose variation ΔD in D98% (dose to 98% volume) of CTV-55 and PTV-55 was -0.66±0.82 and -5.94±3.8 Gy, respectively, in the T+RError. The maximum ΔD (%) for D98% and D0.035cc in CTV-55 was -4.29% and 2.49%, respectively, while in PTV-55 it was -24.9% and 2.36%. The mean dose reduction for D98% in CTV-55 and D98% and D95% in PTV-55 was statistically significant (p<0.05) for TError and T+RError. The mean dose variation for Dmean and D50% in the rectum was statistically significant (p<0.05) for TError and T+RError. CONCLUSION: The uncorrected interfractional 6D setup error results in significant target underdosing and OAR overdosing in prostate cancer. This emphasizes the need to correct interfractional 6D setup errors daily in IMRT and VMAT.

Energy transfer process in a rare earth (Ce3+ , Dy3+ , Sm3+ )-doped nanocrystalline phosphate phosphor.

This work presents the optimized luminescence spectra for the Ce3+ ,Sm3+ -doped NaSrPO4 phosphor that was synthesized using a wet chemical method. Ce3+ and Sm3+ are activator impurities that show spectral splitting bands that corresponds to the d-f and f-f transitions, respectively. These impurity elements shows the characteristics spectral bands when doped with the NaSrPO4 host lattice. Spectral splitting in the Ce3+ excitation band was monitored in the 240-340 nm range, in which the observed bands were located at 269 nm, 292 nm and 321 nm, and emission bands were observed in the broad spectral range 330-430 nm. However, when Sm3+ ion was doped in the same host lattice we obtained a characteristic emission band at 590 and 645 nm in the orange-red region, under sharp excitation bands located at 345, 361, 375, and 403 nm respectively. Also, we carried out energy transfer analysis in the Ce3+ /Dy3+ -doped NaSrPO4 phosphor. Further crystalline phase and the nanophase nature of the phosphor compound were confirmed using X-ray diffraction and transmission electron microscopy analyses.

Review on long afterglow nanophosphors, their mechanism and its application in round-the-clock working photocatalysis.

Semiconductor assisted photocatalysis is one of the most efficient methods for the degradation of complex organic dyes. A major limiting factor of semiconductor assisted photocatalysis is the requirement of a continuous source of light to perform a redox reaction. One of the upcoming solutions is photon energy-storing long afterglow/persistent phosphors. They are an unusual kind of rechargeable, photon energy capturing/trapping phosphors that can trap charge carriers (electrons/holes) in their meta-stable energy levels, thereby resulting in persistent luminescence. Persistence luminescence from such materials can range from minutes to hours. The coupling of long afterglow phosphors (LAP) with the conventional semiconductor is a promising way to support the photocatalytic process even in dark. In addition, dissimilar band structures of LAPs and semiconductor results in formation of heterojunction which further suppresses the recombination of charge. Such an encouraging idea of LAP for round-the-clock working photocatalytic system is in its premature stage; which is required to be investigated fully. Thus, we present a state-of-art review on the potential materials for assisting round-the-clock photocatalysis, trapping-detrapping mechanism in LAP materials, fabrication strategies and their associated characterization tools. Review also covers LAP materials and their photocatalytic mechanism briefly.

Persistent phosphors for luminous paints: A review.

The article briefly reports the fundamental scientific principles and landmarks in the field of luminescence and further enlightens the importance of persistent phosphor that is now widely used in luminous paints. Its main focus is on phosphorescence that makes use of lanthanides that have gained paramount importance in various cross-sections of luminescent applications. Both inorganic and organic afterglow materials, synthesis and characterization along with skilled researchers' essential updates on emerging trends and efforts are elucidated at length. It exclusively reviews the red/green/blue organic/inorganic/hybrid phosphorescent materials and the latest advances in the development of novel long afterglow materials that can accelerate the green technology in the world of luminescence.

Tailoring of thermoluminescent properties and assessment of trapping parameters of natural fluorite samples from Dogargaon fluorite mines, India.

Mineral fluorite or fluorspar (CaF2 ) can host significant quantities of trivalent REE3+ (rare earth element) by substitution with divalent Ca2+ . The fluorites associated with carbonatites are often REE-rich compared to those derived from sedimentary, hydrothermal, or Mississippi Valley-type (MVT) fluorites. The naturally occurring fluorites have several industrial applications one of which is for luminescence. Whether or not REE enriched, the fluorite makes an ideal host for REEs, which are very important phosphors. The naturally occurring fluorites are available in sufficient quantities to cater to the industrial demand. Investigations have been carried out on the fluorites from active fluorite mines at Dongargaon in central India. Thermoluminescence behavior of a natural fluorite sample was investigated using a Nucleonix TL 1009I thermoluminescence reader. Multiple traps formed in the broad thermoluminescent (TL) glow curve were found by TL anal deconvolution software. Trapping parameters for all multiple traps formed on deconvoluting broad TL glow curve were found by different methods like Initial rise method, Chen's Peak shape method and Ilich method.

Investigations on optical properties of Eu0.5 Sm0.5 (TTA)3 tppo hybrid organic complexes molecularly doped in PMMA and PS matrices.

An attempt has been made to synthesize orange-red light-emitting rare earth-doped polymer matrices Eu0.5 Sm0.5 (TTA)3 tppo (Eu = europium, Sm = samarium, TTA = thenoyltrifluoroacetone, tppo = triphenylphosphine oxide) hybrid organic complex by solution technique. Blended thin films were made by molecularly doping the complex in polymethylmethacrylate (PMMA) and polystyrene (PS) polymers at different weight percentages (5%, 10%). These films were solvated in basic and acidic media to explore the effect of solvent on its luminescence properties. UV-visible absorption spectra of these solvated films portray two peaks corresponding to π→π* and n→π* optical transitions in the range 240-275 nm and 370-390 nm in basic medium. Energy band gap of these thin films in basic medium was found between 3.16 eV to 3.20 eV and 3.12 eV to 3.22 eV in acidic medium. Photoluminescence spectra of all films in dichloromethane showed an intense peak at 614 nm, whereas in formic acid, the same were found at 475 nm, which fell in the orange-red and blue region of the visible spectrum, respectively. CIE coordinates of these solvated films in various solvents and at different weight percentages revealed tunable orange-red to blue light emission with change in polarity of the solvent. Therefore the synthesized complexes blended in the polymers can be shaped into flexible films for fabrication of organic light-emitting diodes (OLEDs) with consistent results, proving their prospect as colour tunable light emissive materials for OLED devices, lasers, displays, and solid-state lighting.

Photoluminescence studies and synthesis of BaSO3 Cl2 :Ce3+ blue-emitting lamp phosphor.

The photoluminescence excitation and emission spectra of BaSO3 Cl2 :Ce3+ phosphor were investigated. Excitation wavelength was 323 nm. The phosphor was prepared using a combustion synthesis method. The emission spectrum exhibited a well defined asymmetric band with a maximum at 445 nm for higher emission concentrations. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, photoluminescence and Commission Internationale de l'éclairage colour coordinates; emission intensity was related to relative Ce3+ concentration. These developments enabled the rapid and energy-efficient production of fine particles in the powder form with little expenditure. No additional emission band was observed in the emission spectra, demonstrating that the Ce3+ ion occupied one category of site in the prepared host phosphor.

Thermoluminescence study of CaNa2 (SO4 )2 phosphor doped with Eu3+ and synthesized by combustion method.

In the present study, the thermoluminescence (TL) properties of an Eu3+ -doped CaNa2 (SO4 )2 phosphor were studied. The Eu3+ -doped CaNa2 (SO4 )2 phosphor was synthesized using the combustion method. The samples were well crystallized in the monoclinic phase. The TL glow curve of the Eu3+ -doped CaNa2 (SO4 )2 phosphor showed a single prominent peak at around 210°C with showed linearity on increasing exposure. The response curve of the synthesized phosphor showed linearity in the range 500-7000 Gy. Trapping parameters of synthesized phosphors such as activation energy, frequency factor, and order of kinetics were calculated in the study. These trapping parameters were determined by different methods such as Chen's peak method, the initial rise method, and Ilich's method. Each characteristic of these outcomes demonstrated that the synthesized Eu3+ -doped CaNa2 (SO4 )2 phosphor had outstanding TL properties and might be valuable for TL dosimetry application.

Investigation of thermoluminescence response and trapping parameters of natural barite samples from Dongargaon mine, India.

Dosimetry is a technique that quantitatively measures the ionizing radiation absorbed by matter. The present study was conducted on the barites from a mine at Dongargaon in Central India. Morphological and structural analysis of proposed sample was carried out using X-ray diffraction and standard error of the mean. Thermal analysis and chemical composition of the proposed sample were carried out using thermogravimetric analysis and differential thermal analysis, and electron probe microanalysis. Thermoluminescence (TL) studies on a natural barite sample were performed using a Nucleonix TL1009I TL reader following sample irradiation with γ-rays generated from a 60 Co irradiation source. A broad TL glow curve was observed after TL study that was then deconvoluted using TLanal deconvolution software. Trapping parameters from the sample such as activation energy (E), order of kinetics (b), and frequency factor (s) were calculated using Chen's peak shape method, the initial rise method, and Ilich's method. The results indicated that the natural barite sample could be used in high-dose TL dosimetric applications in various fields.

Thermoluminescence dosimetry properties and kinetic analysis of K3 Ca2 (SO4 )3 F:Dy3+ phosphor.

A trivalent Dy3+ -activated K3 Ca2 (SO4 )3 F fluoride-based phosphor was synthesized using a solid-state reaction method and characterized for its thermoluminescence (TL) application. The crystal structure and surface morphology of the as-synthesized material was analyzed using X-ray diffraction and scanning electron microscopy. A series of the K3 Ca2 (SO4 )3 F:Dy3+ phosphor was irradiated using γ-rays from a 60 Co source and TL glow curves were recorded using a Nucleonix 1009I TL reader. The glow curve of the prepared phosphor showed a prominent single peak at 278°C. TL characteristics were maximum intensity at 1 mol% of Dy3+ ion with a single TL glow peak. The TL glow curve revealed linearity with increase in exposure dose range from 0.1 kGy to 3.0 kGy. Theoretical analysis of the TL glow curve of the γ-ray-irradiated sample was carried out using a computerized glow curve deconvolution method and trapping parameters such as activation energy and frequency factor were calculated using the initial rise method and Ilich's method. The synthesized Dy3+ -doped K3 Ca2 (SO4 )3 phosphor revealed excellent TL properties and was found to be a potential candidate for dosimetric applications.