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).     

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 luminescence in CaMoO4: Eu3+ red phosphor nanoparticles prepared by mechanochemically assisted solid state meta-thesis reaction method

For the first time, CaMoO₄: xEu³⁺ (x = 0.02, 0.04, 0.06, 0.08, 0.1) red phosphor nanoparticles were synthesized using the simple mechanochemically assisted solid state meta-thesis (SSM) reaction method and the luminescence properties as a function of Eu³⁺ ion concentration was investigated. The characteristics of the phosphor materials were analyzed using X-ray diffraction, fourier transform infrared spectroscopy, photoluminescence (PL) and diffuse reflectance spectroscopy. For 8 mol% of Eu³⁺ concentration, the phosphor shows an intensified excitation peak at 392 nm indicating a strong absorption. The PL emission spectra of CaMoO₄: Eu³⁺ phosphors showed an intense peak at 615 nm (red) which corresponds to ⁵D₀ → ⁷F₂ transition of Eu³⁺. The optimal Eu³⁺ concentration in CaMoO₄ phosphors for enhanced red emission occurs for 8 mol% and above this concentration, the emission intensity decreases due to quenching effect. The CIE colour coordinates of the CaMoO₄: 0.08Eu³⁺ red phosphor coincide very well with the standard values of NTSC. The red emission intensity of the SSM prepared CaMoO₄: 0.08Eu³⁺ red phosphor is 4.7 times greater than that of the commercial Y₂O₂S: Eu³⁺ red phosphor and 1.6 times more than the same phosphor prepared by the solid state reaction method.     

Synthesis and characterizations of Dy3+ doped Sr3Al2O6:Eu2+ powder phosphors through citric acid precursor

Sr₃Al₂O₆:Eu²⁺, Dy³⁺ phosphors were synthesized by the polymer precursor method. The X-ray powder diffraction patterns show that the samples have a cubic structure with a space group of Pa3. In the excitation spectrum, the phosphors show a wide absorption in the UV region from 250 to 450 nm, which corresponds to the crystal field splitting of the Eu²⁺ d-orbital. All the emission spectrum of Sr₃Al₂O₆:Eu²⁺, Dy³⁺ phosphors show the broad band emission peaked at about 518 nm, which can be ascribed to the typical 4f⁶5d¹ → 4f⁷ transitions of Eu²⁺ ions. And the best dopant concentration of Dy³⁺ ions for Sr₃Al₂O₆:2 mol%Eu²⁺, xDy³⁺ phosphors is 2 mol%. The excitation wavelengths have no influences on emission peaks, but have clear influences on emission intensities.     

Structural and spectroscopic effects of Ag–Eu3+ codoping of TeO2–PbO glass ceramics

Structural and spectroscopic behavior of TeO₂–PbO–Eu₂O₃ glass ceramics containing small amounts of Ag₂O (0.5 mol%) or metallic Ag nanoparticles (AgNPs) (0.33 mol%) have been studied by varying their Eu₂O₃ content (0–10 mol%). The structural behavior of these samples was investigated by means of X-ray diffraction (XRD), SEM microscopy, and Fourier transform infrared (FTIR) spectroscopy. The average unit-cell parameters, crystallites size, and the quantitative ratio of the crystallographic phases in the samples were evaluated based on XRD data. FTIR spectroscopy data revealed that the TeO₃ and TeO₄ are the main structural units of these glass ceramics and their ratio, TeO₃/TeO₄, changes as function of the europium oxide content and the codoping of the samples. Luminescence spectroscopy measurements evidenced the important peaks located at 438, 550, and 722 nm due to the Pb²⁺ ions and at 589 and 611 nm due to the Eu³⁺ ions present in the studied samples. The presence of AgNPs in the studied glass ceramics determines a considerable enhancement of the luminescence bands of Eu³⁺ ions from 589 and 611 nm.     

Investigation of spectral properties of Eu<Superscript>3+</Superscript> and Tb<Superscript>3+</Superscript> doped strontium zirconium trioxide orthorhombic perovskite for optical and sensing applications

In this paper, the structural, morphological and spectral properties of Eu³⁺ and Tb³⁺ doped strontium zirconium trioxide perovskite phosphors are reported. The samples were synthesized by solid state reaction route with different doping concentrations of Eu³⁺ and Tb³⁺ ions. These synthesized phosphors were characterized by PXRD for structural analysis. The phosphors report orthorhombic structure with average crystallite size of 48 nm. FESEM and HRTEM analysis were done here for topographical and morphological studies. Also, the FTIR spectra of synthesized samples were investigated for functional group analysis. Photoluminescence and thermoluminescence spectra of synthesized samples were studied. On subjecting to 230 nm excitation, the phosphors give three distinct emissions of 596, 610 and 690 nm in the visible region corresponding to ⁵D₀ → ⁷F₁, ⁵D₀ → ⁷F₂ and ⁵D₀ → ⁷F₄ of Eu³⁺ ions. The synthesized samples were also subjected to CIE and Afterglow decay analysis. The average decay lifetime is recorded as 56.24 ns confirming the luminescence decay characteristics of short duration. In TL analysis of these phosphors, second-order kinetics with low activation energy varying from 0.50002 to 0.65668 eV is reported. The enhanced optical characteristics of prepared perovskite phosphor substantiate it as a proficient alternative for photovoltaic, optical and sensing applications.     

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.     

Luminescent properties of YAl3(BO3)4:Eu3+ phosphors

YAL₃(BO₃)₄:Eu³⁺ phosphors were fabricated by the sol-gel method. The structure properties were measured by x-ray diffraction (XRD) and infrared spectra (IR). Doping concentration of Eu³⁺ ions in YAL₃(BO₃)₄:Eu³⁺ phosphors of 0, 1, 3, 4, and 5 mol% were studied. The excitation spectra and emission spectra of YAL₃(BO₃)₄:Eu³⁺ phosphors were examined by fluorescent divide spectroscopy (FDS). The luminescent properties of YAL₃(BO₃)₄:Eu³⁺ phosphors are discussion. The optimal doping concentration of Eu³⁺ ions in YAL₃(BO₃)₄:Eu³⁺ phosphors was found to be approximately 3 mol%.     

The effect of Eu3+ concentration on the Y2O3 host lattice obtained from citrate precursors

This work presents a thermal decomposition study of the precursor resin prepared from the citrate precursor along with structural features and optical properties materials composed by Y₂O₃ and Eu³⁺ containing Y₂O₃ in 0.5, 3, 5 and 7 mol%. The microcrystallite sizes were estimated from the Scherrer equation. The structural and optical properties revealed that the addition of 5 mol% of Eu³⁺ to the Y₂O₃ matrix gave rise to the highest relative emission intensity which was evidenced by the luminescence intensity. The lifetime of the 0.5 mol% Eu³⁺-doped sample suggested two different symmetry sites for Eu³⁺ ions because two different lifetime values were acquired for this sample, while for phosphors doped with 3 or 5 mol% of Eu³⁺ ions only one similar lifetime was observed. When the concentration of Eu³⁺ is 0.5 and 3 mol%, the luminescence intensity is weak due to the low probability of the O^2? - Eu³⁺ charge transfer transition. On the other hand, when the concentration of the Eu³⁺ ions is 7 mol%, a quenching effect is evidenced.     

Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) tricolor emission phosphors and their application for near-UV white light-emitting diode

Tricolor emission Ca₂SiO₄:Ln (Ln = Ce³⁺, Eu²⁺, Sm³⁺) phosphors were synthesized by the conventional solid-state reaction method, and their photoluminescence properties were investigated. Ce³⁺-, Eu²⁺-, or Sm³⁺-doped Ca₂SiO₄ phosphors showed typical blue, green, or red luminescence in the CIE1931 chromaticity diagram, respectively. In addition, the luminescence efficiency of the tricolor emission Ca₂SiO₄:Ln (Ln = Ce³⁺, Eu²⁺, Sm³⁺) phosphors was evaluated. A series of white light-emitting diode (LED) prototypes were fabricated by combining near-UV LED chip and the as-prepared tricolor emission phosphors with various ratios in weight. White LED prototypes with tunable correlated color temperature and color-rendering index values were realized by controlling the amount of phosphors. The presented results indicated the potential application of Ca₂SiO₄:Ln (Ln = Ce³⁺, Eu²⁺, Sm³⁺) phosphors in near-UV white LED.     

Thermally stimulated luminescence and photoluminescence investigations of Eu3+ and Eu2+ doped SrBPO5

Thermally stimulated luminescence (TSL) investigations of SrBPO₅:Eu^3?+ and SrBPO₅:Eu^2?+ phosphors were carried out in the temperature range of 300–650 K. In order to characterize the phosphors, X-ray diffraction and photoluminescence (PL) techniques were used. The emission spectrum of air heated SrBPO₅:Eu^3?+ phosphor exhibited emission bands at 590, 614, 651 and 702 nm under 248 nm excitation, assigned to transitions of Eu^3?+ ion. In phosphor prepared in reducing (Ar + 8% H₂) atmosphere, a broad emission band due to Eu^2?+ ranging from 350 to 400 nm was observed with 340 nm excitation. EPR studies have confirmed the presence of Eu^2?+ ions in the samples prepared in reducing atmosphere. TSL glow curve of SrBPO₅:Eu^3?+ had shown intense peaks around 397, 510, 547 K and a weak peak around 440 K whereas in case of SrBPO₅:Eu^2?+ system, glow peaks at 414, 478 and weak peak at 516 nm were observed. The shift in TSL glow pattern can be attributed to stabilization of different oxidation states of the dopant ion in the host lattice. Apart from this, TSL trap parameters such as trap depth and frequency factor were determined. Spectral characteristics of TSL emission have shown that Eu^3?+?/Eu^2?+ ion acts as the luminescent centre in the respective phosphors.     

Influence of the Eu3+ dosage concentration on luminescence properties of YPO4:Eu3+ microspheres

In this study, YPO₄:Eu³⁺ microspheres with different Eu³⁺ dosage concentration were fabricated by a facile hydrothermal route at 200 °C for 10 h in the presence of citric acid. The YPO₄:Eu³⁺ samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and luminescence spectroscopy. The XRD results reveal that the YPO₄:Eu³⁺ samples presented a tetragonal structure. The TEM and SEM observations demonstrate that the YPO₄:Eu³⁺ samples with uniform sphere-like morphologies can be obtained at 200 °C for 10 h. The sizes of samples are in the range of 2–2.2 μm. The room temperature luminescence properties of YPO₄:Eu³⁺ samples were studied using an excitation wavelength of 227 nm. The emission spectrum displays the bands associated to the ⁵D₀ → ⁷F_J (J = 1, 2 and 4) electronic transitions characteristics of the Eu³⁺ cations at different positions. The influence of Eu³⁺ dosage concentration on luminescence properties of YPO₄:Eu³⁺ microspheres were studied carefully.     

Synthesis and luminescence properties of novel β-Zn3BPO7:Ln (Ln = Ce3+, Eu2+, Eu3+) phosphors

This work first reports the synthesis and luminescence properties of rare earth Ce³⁺, Eu²⁺, Eu³⁺ ions doped β-Zn₃BPO₇ phosphors [β-Zn₃BPO₇:Ln (Ln = Ce³⁺, Eu²⁺, Eu³⁺)]. The phosphors were synthesized by a solid-state reaction at high temperature, and their luminescence properties were investigated by measuring the photoluminescence excitation and emission spectra. The f–d transitions of Ce³⁺ and Eu²⁺ ions in the host lattice are assigned and corroborated, which lead to the broad emission band in ultraviolet (UV) and visible region for Ce³⁺ and Eu²⁺ ions under UV excitation, respectively. Typical reddish orange emission from Eu³⁺ in the host lattice was also observed. The spectroscopic characteristics including Stokes shift, crystal field depression, electron–vibrational interaction, and charge transfer band were investigated and compared with that in other borophosphate phosphors. β-Zn₃BPO₇:Eu²⁺ and β-Zn₃BPO₇:Eu³⁺ phosphors show potential application in solid state lighting region.     

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.     

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.     

Dependence of photoluminescence (PL) emission intensity on Eu and ZnO concentrations in Y2O3:Eu and ZnO·Y2O3:Eu nanophosphors

Y₂O₃:Eu³⁺ and ZnO·Y₂O₃:Eu³⁺ nanophosphor powders with different concentrations of Eu³⁺ ions were synthesized by a sol-gel method and their luminescence properties were investigated. The red photoluminescence (PL) from Eu³⁺ ions with the main emission peak at 612 nm was observed to increase with Eu³⁺ concentration from 0.25 to 0.75 mol% and decreased notably when the concentration was increased to 1 mol%. The decrease in the PL intensity at higher Eu³⁺ concentrations can be associated with concentration quenching effects. The red emission at 612 nm was shown to increase considerable when ZnO nanoparticles were incorporated in Y₂O₃:Eu³⁺ while green emission from ZnO was suppressed. The increase is attributed to energy transfer from ZnO to Eu³⁺.     

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.     

Comparative study of Ca3Bi(PO4)3:Eu3+ phosphors prepared by three methods

Ca₃Bi(PO₄)₃:Eu³⁺ phosphors were synthesized by solid-state (SS) reaction, co-precipitation (CP) and sol–gel methods. The resulting phosphors were well characterized by X-ray diffraction, field-emission scanning electron microscopy and photoluminescence spectra. The X-ray diffraction results suggested that the pure phase of Ca₃Bi(PO₄)₃:Eu³⁺ can be obtained by SS reaction and CP method. The phosphors obtained by CP method showed more homogeneous, agglomerate-free particles. The samples obtained by the CP method showed the highest emission intensity among the three methods which fired at 1,000 °C for 2 h. It was showed that the CP method was the most respected process for the preparation of Ca₃Bi(PO₄)₃:Eu³⁺ phosphors.     

Strong luminescence enhancement of Li2CaSiO4:Eu2+ phosphors by codoping with La3+

La³⁺ ions codoped Li₂CaSiO₄:Eu²⁺ phosphors were synthesized through the solid state reaction method. Large increases in the emission could be achieved by adding La³⁺ in the host. The optimum doping concentration expressed by the x value in Li₂Ca_0.99?xSiO₄:0.01Eu²⁺, xLa³⁺ was determined to be of 0.01. X-ray diffraction patterns revealed that the samples maintained Li₂CaSiO₄ single phase after codoping Eu²⁺ and La³⁺. The excitation spectra of samples showed a broad absorption band ranging from 220 to 450 nm and the emission spectra excited at 375 nm showed the typical broad band of Eu²⁺ peaks at about 478 nm (4f⁶5d¹–4f⁷). The broad absorption band wavelength was found to be matched appropriately with the emission wavelength of commercially available blue LEDs. Fluorescent lifetime test results showed that the La³⁺ codoped could increase the excited state energy and prolong the lifetime of Eu²⁺. The optimization mechanism was studied in detail by the case of La³⁺ codoping. The temperature dependent luminescence measurements show that the thermal quenching remains small in the case of La³⁺ doping, in other word, La³⁺ codoped Li₂CaSiO₄:Eu²⁺ phosphor has a good thermal stability. These results provided a useful basis for further improving the luminescence performance of Li₂CaSiO₄:Eu²⁺ phosphors.     

Synthesis and luminescent properties of Tb3+ activated AWO4 based (A = Ca and Sr) efficient green emitting phosphors

Optically efficient terbium activated alkaline earth metal tungstate nano phosphors (AWO₄ [A = Ca, Sr]) with different doping concentrations have been prepared by mechanochemically assisted solid state metathesis reaction at room temperature for the first time. The prepared phosphors were characterized by the X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), Fourier transform Raman (FT-Raman) spectroscopy, photoluminescence and diffuse reflectance spectroscopy measurements. The XRD and Raman spectra results showed that the prepared powders present a scheelite-type tetragonal structure. FTIR spectra exhibited a high absorption band situated at around 850 cm^?1, which was ascribed to the W–O antisymmetric stretching vibrations into the [WO₄]^2? tetrahedron groups and the SEM images reveal that the particle sizes were in the range of 20–60 nm. The excitation and the emission spectra were measured to characterize the luminescent properties of the phosphors. The excitation spectrum exhibits a charge transfer broad band along with some sharp peaks from the typical 4f–4f transitions of Tb³⁺. Under excitation of UV light, these AWO₄:xTb³⁺ (A = Ca, Sr) phosphors showed a strong emission band centered at 545 nm (green) which corresponds to ⁵ D ₄ → ⁷ F ₅ transition of Tb³⁺. Analysis of the emission spectra with different Tb³⁺ concentrations revealed that the optimum dopant concentration for CaWO₄:xTb³⁺ and SrWO₄:xTb³⁺ phosphors are about 8 and 6 mol% of Tb³⁺. The green emission intensity of the solid state meta-thesis prepared CaWO₄:0.08Tb³⁺ and SrWO₄:0.06Tb³⁺ phosphors are 1.5 and 1.2 times greater than that of the commercial LaPO₄:Ce, Tb green phosphor. All properties show that AWO₄:Tb³⁺ (A = Ca, Sr) is a very appropriate green-emitting phosphor for fluorescent lamp applications.