Tunable luminescence and energy transfer properties in YVO<Subscript>4</Subscript>:Bi<Superscript>3+</Superscript>,Ln<Superscript>3+</Superscript> (Ln = Dy,Sm, Eu) phosphors prepared by microwave sintering method

YVO₄:Bi³⁺,Ln³⁺ (Ln?=?Dy, Sm, Eu) phosphors were successful synthesized by microwave sintering method, and characterized by X-ray powder diffraction, scanning electron microscope, photoluminescence spectra, lifetime, quantum efficiency and general structure analysis system structure refinement. Refinement results indicated that the introduced ions occupy the sites of Y³⁺. Under 275 nm excitation, the luminescent intensity of YVO₄:Bi³⁺ samples reach the maximum when Bi³⁺ concentration is 0.02, the broad excitation spectrum of YVO₄:Bi³⁺ has a strongest peak at near 343 nm. Doped Bi³⁺ can effectively improve the emission intensity of YVO₄:Ln³⁺. The energy transfer mechanism of Bi³⁺?→?Ln³⁺ was dipole-quadrupole mechanism of electric multipole interaction. The critical distance (R_c) between Ln³⁺ and Bi³⁺ were calculated by concentration quenching method. Emitting color of YVO₄:Bi³⁺,Ln³⁺ phosphors were tunable by adjusting Ln³⁺ content. In a word, the material has a good application prospects on light emitting diodes.     

Single phased Sr<Subscript>3</Subscript>La(PO<Subscript>4</Subscript>)<Subscript>3</Subscript>:Eu<Superscript>2+</Superscript>/Mn<Superscript>2+</Superscript> phosphors: solid state synthesis,tunable luminescence and potential applications in white light LEDs

A series of Sr₃La(PO₄)₃:Eu²⁺/Mn²⁺ phosphors were synthesized by a solid state reaction. The phase and the optical properties of the synthesized phosphors were investigated. The XRD results indicate that the doped Eu²⁺ and Mn²⁺ ions do not change the phase of Sr₃La(PO₄)₃. The peak wavelengths of Eu²⁺ single doped and Eu²⁺/Mn²⁺ codoped Sr₃La(PO₄)₃ phosphors shift to longer wavelength due to the larger crystal field splitting for Eu²⁺ and Mn²⁺. The increases of crystal field splitting for Eu²⁺ and Mn²⁺ are induced by the substitution of Sr²⁺ by Eu²⁺ and Mn²⁺ in Sr₃La(PO₄)₃ host. Due to energy transfer from Eu²⁺ to Mn²⁺ in Sr₃La(PO₄)₃:Eu²⁺/Mn²⁺ phosphors, tunable luminescence was obtained by changing the concentration of Mn²⁺. And the white light was emitted by Sr₃La(PO₄)₃:3.0 mol%Eu²⁺/4.0 mol%Mn²⁺ and Sr₃La(PO₄)₃:3.0 mol%Eu²⁺/5.0 mol%Mn²⁺ phosphors.     

Optical properties of Eu<Superscript>3+</Superscript> activated SrLa<Subscript>2</Subscript>O<Subscript>4</Subscript> red-emitting phosphors for WLED applications

The SrLa_2?xO₄:xEu³⁺ phosphors are synthesized through high-temperature solid-state reaction method at 1473 K with various doping concentration. Their phase structures, absorption spectra, and luminescence properties are investigated by X-ray diffraction (XRD), UV–Vis spectrophotometer and photoluminescence spectrometry. The intense absorption of SrLa_2?xO₄:xEu³⁺ phosphors have occurred around 400 nm. The prominent luminescence spectra of the prepared phosphors exhibited bright red emission at 626 nm. The doping concentration 0.12 mol% of Eu³⁺ is shown to be optimal for prominent red emission and chromaticity coordinates are x?=?0.692, y?=?0.3072. Considering the high colour purity and appropriate emission intensity of Eu³⁺ doped SrLa₂O₄ can be used as red phosphors for white light emitting diodes (WLEDs).     

Hydrothermal synthesis of NaLa(WO<Subscript>4</Subscript>)<Subscript>2</Subscript>:Eu<Superscript>3+</Superscript> octahedrons and tunable luminescence by changing Eu<Superscript>3+</Superscript> concentration and excitation wavelength

NaLa(WO₄)₂:Eu³⁺ phosphors with different Eu³⁺ concentrations have been synthesized by a hydrothermal method. The phase is confirmed by XRD analysis, which shows a pure-phase NaLa(WO₄)₂ XRD pattern for all of NaLa(WO₄)₂:Eu³⁺ phosphors. The SEM and TEM images indicate that all of NaLa(WO₄)₂:Eu³⁺ phosphors have a octahedral morphology. These suggest that the Eu³⁺ doping has no influence on the structure and growth of NaLa(WO₄)₄ particles. By monitoring the emission of Eu³⁺ at 615 nm, NaLa(WO₄)₂:Eu³⁺ phosphors show excitation bands originating from both host and Eu³⁺ ions. Under the excitation at 271 nm corresponding to WO₄ ^2? groups, emission bands coming from the ¹A₁ → ³T₁ transition with the WO₄ ^2? groups and the ⁵D₀ → ⁷F_j (j = 0, 1, 2, 3 and 4) transitions of Eu³⁺ are observed. The emission intensity relating to WO₄ ^2? groups decreases with increasing Eu³⁺ concentration. But emission intensities of Eu³⁺ increase firstly and then decreases because of concentration quenching effect. Under the excitation at 395 nm corresponding to ⁷F₀ → ⁵L₆ transition of Eu³⁺, only characteristic Eu³⁺ emission bands can be observed. The results of this work suggest that tunable luminescence can be obtained for Eu³⁺ doped NaLa(WO₄)₂ phosphors by changing Eu³⁺ concentration and excitation wavelength.     

Study of the effect of Li<Superscript>+</Superscript> concentration on the photoluminescence properties of Y<Subscript>2</Subscript>O<Subscript>3</Subscript>:Eu<Superscript>3+</Superscript> phosphors

Y₂O₃:Eu³⁺ phosphors were prepared by hydrothermal method. Effect of the doping concentration of Eu³⁺ on the photoluminescence properties of Y₂O₃:Eu³⁺ phosphor was studied in details. It was found that the strongest emission intensity is achieved as atomic ratio of Y³⁺ to Eu³⁺ is 8. As concentration of Eu³⁺ exceeds the critical concentration, the emission intensity decreases dramatically due to the concentration quenching of Eu³⁺. Also, the effect of Li⁺ on the photoluminescence performance of the Y₂O₃:Eu³⁺ phosphor is studied in this work. According to the results, the doping of Li⁺ may greatly improve the PL performance of the Y₂O₃:Eu³⁺ phosphors due to the flux effect and improved crystallinity caused by the doping of Li⁺.     

Influence of microstructure on the luminescence properties of YVO<Subscript>4</Subscript>:Eu<Superscript>3+</Superscript> nanoparticles

YVO₄:Eu³⁺ nanoparticles were synthesized by hydrothermal method at different conditions. The microstructures and photoluminescence (PL) properties of the as-prepared YVO₄:Eu³⁺ nanoparticles were investigated by X-ray powder diffraction, field emission scanning electron microscopy and PL spectroscopy. The detailed relationship between the microstructures and luminescence properties was investigated. It has been found that the crystallinity, the grain size and the duty factor of Eu³⁺ play important roles in influencing the luminescence properties. The article is published in the original.     

Tunable luminescence properties and energy transfer of single-phase Ca<Subscript>4</Subscript>(PO<Subscript>4</Subscript>)<Subscript>2</Subscript>O: Dy<Superscript>3+</Superscript>, Eu<Superscript>2+</Superscript> multi-color phosphors for warm white light

The novel Ca_4?x(PO₄)₂O: xDy³⁺ and Ca_4?x?y(PO₄)₂O: xDy³⁺, yEu²⁺ multi-color phosphors were synthesized by traditional solid-state reaction. The crystal structure, particle morphology, photoluminescence properties and energy transfer process were investigated in detail. The X-ray diffraction (XRD) results demonstrate that the products showed pure monoclinic phase of Ca₄(PO₄)₂O when x < 0.1. The scanning electron microscopy (SEM) indicated that the phosphors were grain-like morphologies with diameters of ~ 3.7–7.0 μm. Under excitation of 345 nm, Dy³⁺-doped Ca₄(PO₄)₂O phosphors showed multi-color emission bands at 410, 481 and 580 nm originated from oxygen vacancies and Dy³⁺. Interestingly, Ca₄(PO₄)₂O: Dy³⁺, Eu²⁺ phosphors exhibited blue emission band at 481 nm and broad emission band from 530 to 670 nm covering green to red regions. The energy transfer process from Dy³⁺ to Eu²⁺ was observed for the co-doped samples, and the energy transfer efficiency reached to 60% when Eu²⁺ molar concentration was 8%. In particular, warm/cool/day white light with adjustable CCT (2800–6700 K) and high CRI (R_a > 85) can be obtained by changing the Eu²⁺ co-doping contents in Ca₄(PO₄)₂O: Dy³⁺, Eu²⁺ phosphors. The optimized Ca_3.952(PO₄)₂O: 0.04Dy³⁺, 0.008Eu²⁺ phosphor can achieve the typical white light with CCT of 4735 K and CRI of 87.     

Photoluminescence properties of a novel red-emitting phosphor Ba<Subscript>2</Subscript>LaV<Subscript>3</Subscript>O<Subscript>11</Subscript>:Eu<Superscript>3+</Superscript>

Ba₂LaV₃O₁₁:Eu³⁺ phosphors were firstly synthesized by the traditional solid-state reaction method at 1100 °C. Their luminescence properties were investigated by photoluminescence excitation and emission spectra. The excitation spectrum shows a broad band centered at about 275 nm in the region from 200 to 370 nm, which is attributed to an overlap of the charge transfer transitions of O^2??→?V⁵⁺ and O^2??→?Eu³⁺. The phosphors exhibit the red emissions of Eu³⁺ and the emission intensity ratio of ⁵D₀?→?⁷F₂ to ⁵D₀?→?⁷F₁ is dependent on the Eu³⁺ concentration due to an environment change about Eu³⁺ ions. Concentration quenching occurs at 30 mol% in the phosphors and exchange interaction is its main mechanism. Ba₂LaV₃O₁₁:Eu³⁺ displays tunable CIE color coordinates from yellow orange to red depended on Eu³⁺ content, which may have a potential application for illuminating and display devices.     

Enhanced red-emitting phosphor Na<Subscript>2</Subscript>Ca<Subscript>3</Subscript>Si<Subscript>2</Subscript>O<Subscript>8</Subscript>:Eu<Superscript>3+</Superscript> by charge compensation

A series of novel red-emitting Na₂Ca_3???x Si₂O₈:xEu³⁺ phosphors were synthesized by solid state reactions. The phosphors can strongly absorb 395 nm light, and show red emission with a good color purity. The excitation and emission spectra properties of Na₂Ca₃Si₂O₈:Eu³⁺ were characterized. Na₂Ca₃Si₂O₈:Eu³⁺ with self-compensated and alkali metal ions charge compensated approaches (2Ca²⁺→Eu³⁺ + M⁺, M?=?Li⁺, Na⁺, K⁺) have investigated, which found that the red emission of luminescent intensity can be greatly enhanced, and shows superior luminescent property to the commercial Y₂0₃S:Eu³⁺. The present work implies that the efficient charge compensated phosphors are promising candidates as red-emitting phosphor for w-LEDs.     

Synthesis and annealing effects on the optical spectroscopy properties of red-emitting Gd(P<Subscript>0.5</Subscript>V<Subscript>0.5</Subscript>)O<Subscript>4</Subscript>: x at.% Eu<Superscript>3+</Superscript>

In this work, Gd(P_0.5V_0.5)O₄: x at.% Eu³⁺ phosphors with different dopant concentrations (x?=?1, 3, 5, 6, 7, 9) were synthesized through chemical coprecipitation method. The phosphors were characterized by XRD, SEM, infrared spectroscopy, photoluminescence excitation, emission spectra and CIE. The results of XRD indicate that the obtained phosphors have the tetragonal phase structure. Eu³⁺ emission transitions arise mainly from the ⁵D₀ level to the ⁷F_J (J?=?0, 1, 2, 3, 4) manifolds. The emission intensity and crystalline of Gd(P_0.5V_0.5)O₄:x at% Eu³⁺ powders are increasing with annealing temperature at 600, 800, 1000, 1100, and 1200 °C, respectively. The introduction of VO₄^3? can broaden the range of UV excitation spectrum wavelength and enhance the transition between ⁵D₀ → ⁷F₁ to ⁵D₀ → ⁷F₂ for long wavelength emission. And the most dominant emission peak of Eu³⁺ for ⁵D₀ → ⁷F₂ transition is closer to pure red light at 622 nm. The maximum emission intensity of the phosphors is the concentration of 6 at.% Eu³⁺ because of the distance of the neighbor Eu³⁺ ions reaching a certain critical value and the influence of multipolar interaction. Compared to commercial phosphors Y₂O₃:Eu³⁺ and (Y,Gd)BO₃:Eu³⁺, our work yielded a longer wavelength red light emission intensity and a higher proportion of red light to orange light. All our results indicate that color purity of this phosphor turns it into a promising red phosphor in ultraviolet-pumped light-emitting diodes.     

Luminescence properties of Bi codoped and P codoped Ca<Subscript>3</Subscript>(VO<Subscript>4</Subscript>)<Subscript>2</Subscript>:Eu<Superscript>3+</Superscript>

New red emitting phosphors, Ca₃(VO₄)₂:Eu³⁺,Bi³⁺, Ca₃((P,V)O₄)₂:Eu³⁺ were synthesized by low temperature solid-state reaction and characterized by X-ray diffraction, scanning electron microscopy, photoluminescence spectra and Fourier transform infrared spectroscopy. The results show that the red emission located at about 613 nm was ascribed to ⁵ D ₀-⁷ F ₂ transition of Eu³⁺. The effect of by Bi doping and by P doping was also investigated systematically.     

Synthesis and photoluminescence properties of LiEu(W,Mo)<Subscript>2</Subscript>O<Subscript>8</Subscript>:Bi<Superscript>3+</Superscript> red-emitting phosphor for white-LEDs

LiEu_1−x (W_2−y Mo _y )O₈:xBi³⁺ series red-emitting phosphors were synthesized by solid state reaction. The structure, morphology, and photoluminescent properties of phosphors were studied by X-ray powder diffraction, scanning electron microscopy, and photoluminescence spectrum, respectively. X-ray powder diffraction analysis showed that the as-obtained phosphors belong to the scheelite structure. The average particle size of the investigated phosphor was about 8 μm. The excitation spectrum exhibits a charge-transfer broad band along with some sharp peaks from the typical 4f–4f transitions of Eu³⁺. Under excitation of UV, near-UV, or blue light, these phosphors showed strong red emission at 615 nm due to ⁵D₀–⁷F₂ transition of Eu³⁺. The incorporation of Mo⁶⁺ into LiEuW₂O₈:Bi³⁺ could induce red-shift of the charge-transfer broad band and a remarkable increase of photoluminescence. The highest red-emission intensity was observed with LiEu_0.80Mo₂O₈:0.20Bi³⁺. Compared with the commercial red-emitting phosphor, Y₂O₂S:Eu³⁺, the emission intensity of LiEu_0.80Mo₂O₈:0.20Bi³⁺ phosphor is much stronger than that of Y₂O₂S:Eu³⁺ and its chromaticity coordinates are closer to the standard values than that of the commercial phosphor. The optical properties of LiEu_0.80Mo₂O₈:0.20Bi³⁺ phosphor make it attractive for the application in white-light-emitting diodes (LEDs), in particular for near-UV InGaN-based white-LEDs.     

Roles of doping ions in persistent luminescence of SrAl<Subscript>2</Subscript>O<Subscript>4</Subscript>:Eu<Superscript>2+</Superscript>, RE<Superscript>3+</Superscript> phosphors

The polycrystalline Eu²⁺ and RE³⁺ co-doped strontium aluminates SrAl₂O₄:Eu²⁺, RE³⁺ were prepared by solid state reactions. The UV-excited photoluminescence, persistent luminescence and thermo-luminescence of the SrAl₂O₄:Eu²⁺, RE³⁺ phosphors with different composition and doping ions were studied and compared. The results showed that the doped Eu²⁺ ion in SrAl₂O₄:Eu²⁺, Dy³⁺ phosphors works as not only the UV-excited luminescent center but also the persistent luminescent center. The doped Dy³⁺ ion can hardly yield any luminescence under UV-excitation, but can form a electron trap with appropriate depth and greatly enhance the persistent luminescence and thermo-luminescence of SrAl₂O₄:Eu²⁺. Different co-doping RE³⁺ ions showed different effects on persistent luminescence. Only the RE³⁺ ion (e.g. Dy³⁺, Nd³⁺), which has a suitable optical electro-negativity, can form the appropriate electron trap and greatly improve the persistent luminescence of SrAl₂O₄:Eu²⁺. Based on above observations, a persistent luminescence mechanism, electron transfer model, was proposed and illustrated.     

Rapid synthesis and enhancement in down conversion emission properties of BaAl<Subscript>2</Subscript>O<Subscript>4</Subscript>:Eu<Superscript>2+</Superscript>,RE<Superscript>3+</Superscript> (RE<Superscript>3+</Superscript>=Y,Pr) nanophosphors

BaAl₂O₄:Eu²⁺,RE³⁺ (RE³⁺=Y, Pr) down conversion nanophosphors were prepared at 600 °C by a rapid gel combustion technique in presence of air using boron as flux and urea as a fuel. A comparative study of the prepared materials was carried out with and without the addition of boric acid. The boric acid was playing the important role of flux and reducer simultaneously. The peaks available in the XPS spectra of BaAl₂O₄:Eu²⁺ at 1126.5 and 1154.8 eV was ascribed to Eu²⁺(3d _5/2) and Eu²⁺(3d _3/2) respectively which confirmed the presence of Eu²⁺ ion in the prepared lattice. Morphology of phosphors was characterized by tunneling electron microscopy. XRD patterns revealed a dominant phase characteristics of hexagonal BaAl₂O₄ compound and the presence of dopants having unrecognizable effects on basic crystal structure of BaAl₂O₄. The addition of boric acid showed a remarkable change in luminescence properties and crystal size of nanophosphors. The emission spectra of phosphors had a broad band with maximum at 490–495 nm due to electron transition from 4f ⁶5d ¹ → 4f ⁷ of Eu²⁺ ion. The codoping of the rare earth (RE³⁺=Y, Pr) ions help in the enhancement of their luminescent properties. The prepared phosphors had brilliant optoelectronic properties that can be properly used for solid state display device applications.     

Photoluminescence properties and charge compensation investigations of novel orange-emitting Eu<Superscript>3+</Superscript> doped Na<Subscript>4</Subscript>Ca<Subscript>4</Subscript>(Si<Subscript>6</Subscript>O<Subscript>18</Subscript>) phosphors

A series of polycrystalline Na₄Ca₄(Si₆O₁₈):Eu³⁺ orange emitting phosphors were synthesized by a conventional high-temperature solid-state reaction. The phase formation was confirmed by X-ray power diffraction analysis. The excitation spectra show a strong host absorption indicating an efficient energy transfer process from O^2? to Eu³⁺ ions. Upon NUV radiation, the phosphors showed strong red emission around 610 nm (⁵D₀ → ⁷F₂) and orange emission around 591 nm (⁵D₀ → ⁷F₁), but the ⁵D_1,2,3 emission nearly can not be seen. Compared with the luminescence properties of Li⁺, Na⁺, and K⁺ co-doped samples, we deduced that Na⁺ ions probably prefer to dope into the intrinsic Na vacancies rather than Ca²⁺ ions vacancies in Na₄Ca₄(Si₆O₁₈) crystal. Thermal stability properties, quantum efficiency and chromaticity coordinates of the phosphors have been investigated for the potential application in white LEDs.     

Tunable luminescence of SrLaMgTaO<Subscript>6</Subscript>:Sm<Superscript>3+</Superscript> phosphors due to energy transfer from TaO<Subscript>6</Subscript> group to Sm<Superscript>3+</Superscript> ion

A series of SrLaMgTaO₆:Sm³⁺ phosphors were synthesized through a solid state reaction. The phase, microstructure and luminescent properties of the synthesized phosphors were investigated through techniques of XRD, SEM and spectrophotometer. The XRD patterns show that the synthesized phosphors have the same phase structure. The SEM images show that the synthesized phosphors are microcrystallines in the range of 1.2–3.4 µm. SrLaMgTaO₆:Sm³⁺ phosphors present emission bands originating from TaO₆ group and Sm³⁺ ions. The critical concentration of Sm³⁺ in SrLaMgTaO₆ is found to be 7 mol%. Due to energy transfer from TaO₆ group to Sm³⁺, tunable luminescence is obtained by changing Sm³⁺ doping concentration.     

Facile hydrothermal synthesis for size-controlled YVO<Subscript>4</Subscript>:Eu<Superscript>3+</Superscript> micro/nanosheets and its luminescence properties

Homogeneous and size-controlled YVO₄:Eu³⁺ micro/nanosheets were successfully synthesized on a large scale by using an ammonium oxalate (AO)-assisted hydrothermal route and post-calcination process. In this study, the shape and size of the as-prepared architectures can be changed effectively by controlling a series of experimental parameters, such as the precursor’s reaction temperature, hydrothermal reaction time and molar ratio of organic additive AO:Y³⁺. YVO₄:Eu³⁺ micro/nanosheets were synthesized with lengths ranging from 2000 to 400 nm and thicknesses ranging from 200 to 50 nm. When changing the precursor’s reaction temperature and reducing the hydrothermal reaction time to 2 h, the phase composition was transformed into Y₂O₃ instead of YVO₄. Functioning as a precipitant and shape modifier, AO exerted a dynamic effect by adjusting the growth rate of different facets under the various experimental conditions, resulting in the formation of different shapes and sizes of the final products. The correlative growth mechanism was analyzed in detail. Photoluminescence and Electroluminescence properties of the products exhibited a strong red emission focused on 618 nm under 275 nm ultraviolet excitation or direct current high-voltage field. Small sample sizes exhibited high EL intensity. The size-controlled products synthesized successfully via the hydrothermal method could provide a great opportunity for systematically evaluating their luminescence properties and accelerating the use of different types of applications in color display devices.     

Synthesis,photoluminescence and mechanoluminescence properties of Eu<Superscript>3+</Superscript> ions activated Ca<Subscript>2</Subscript>Gd<Subscript>2</Subscript>W<Subscript>3</Subscript>O<Subscript>14</Subscript> phosphors

A new series of Eu³⁺ ions-activated calcium gadolinium tungstate [Ca₂Gd₂W₃O₁₄] phosphors were synthesized by conventional solid-state reaction method. The X-ray diffraction patterns of the powder samples indicate that the Eu³⁺: Ca₂Gd₂W₃O₁₄ phosphors are of tetragonal structure. The prepared phosphors were well characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL), and mechanoluminescence (ML) spectra. PL spectra of Eu³⁺: Ca₂Gd₂W₃O₁₄ powder phosphors have shown strong red emission at 615 nm (⁵D₀ → ⁷F₂) with an excitation wavelength λ _exci = 392 nm (⁷F₀ → ⁵L₆). The energy transfer from tungstate groups to europium ions has also reported. Mechanoluminescence studies of Eu³⁺: Ca₂Gd₂W₃O₁₄ phosphors have also been explained systematically.     

Synthesis,tunable luminescence and thermal stability of Mg<Subscript>2</Subscript>Al<Subscript>4</Subscript>Si<Subscript>5</Subscript>O<Subscript>18</Subscript>:Ce<Superscript>3+</Superscript>/Mn<Superscript>2+</Superscript> phosphors

Ce³⁺/Mn²⁺ singly doped and codoped Mg₂Al₄Si₅O₁₈ phosphors were synthesized by a solid state reaction. The phase, luminescent properties and thermal stability of the synthesized phosphors were investigated. Ce³⁺ and Mn²⁺ singly doped Mg₂Al₄Si₅O₁₈ phosphors show emission bands locating in blue and yellow–red regions, respectively. In Ce³⁺ and Mn²⁺ codoped Mg₂Al₄Si₅O₁₈, tunable luminescence was obtained because of the energy transfer from Ce³⁺ to Mn²⁺. In Mg₂Al₄Si₅O₁₈:Ce³⁺/Mn²⁺ phosphors with a fixed Ce³⁺ concentration, energy transfer efficiency increases with the increasing Mn²⁺ concentration, which is confirmed by the continually decreasing intensity and shortening decay time of Ce³⁺ emission. Moreover, the luminescent properties and thermal stability provide a great significance on the applications in the field of light emitting diodes.     

Luminescence studies on Eu<Superscript>2+</Superscript> and Tb<Superscript>3+</Superscript> doped Ca<Subscript>2</Subscript>MgSi<Subscript>2</Subscript>O<Subscript>7</Subscript> phosphors

Eu²⁺ and Tb³⁺ doped Ca₂MgSi₂O₇ phosphors were synthesized by conventional solid-state reaction. The phase formation was confirmed by X-ray powder diffraction technique and refined lattice parameters were calculated by rietveld refinement process using Celref v3. The photoluminescence (PL) excitation and emission spectra were investigated. The phosphors exhibited broaden green emitting luminescence peaking at 520 nm when excited at 374 nm source. Morphological studies were carried out using Scanning electron microscopy (SEM) images of the sample with optimum PL emission. The dependence of photoluminescence intensity on co-dopant concentration and the kinetic parameters were also reported. Time resolved fluorescence spectroscopy (TRFS) is used to investigate the decay in luminescence signals with respect to time. The sample proved to be a good long lasting material, which makes it useful in emergency signs, textile printing, textile exit sign boards and electronic instrument dial pads etc.