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.     

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 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.     

Luminescence property of Ca<Subscript>3</Subscript>(VO<Subscript>4</Subscript>)<Subscript>2</Subscript>:Eu<Superscript>3+</Superscript> dependence on molar ratio of Ca/V and solution combustion synthesis temperature

Red emitting phosphor Ca₃(VO₄)₂:Eu³⁺ was prepared by citric acid-assisted solution combustion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and fluorescence spectrophotometer. The influences of Ca to V molar ratio and synthesis temperature on phase composition, morphology, grain size, photofluorescence properties, and ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS) of as-synthesized samples were investigated. The results indicate that Ca to V molar ratio play a key role for the changing of phase composition, excitation spectrum, and luminescence intensity. The sample prepared at 900 °C, keeping Ca/V = 3:2.2, has the highest photoluminescence intensity. The possible causes of the effects on photoluminescence mechanism were also discussed in this work.     

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.     

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.     

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.     

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.     

Ce and Eu activated Na<Subscript>2</Subscript>Zn<Subscript>5</Subscript>(PO<Subscript>4</Subscript>)<Subscript>4</Subscript>, a new promising novel phosphor

A new efficient phosphor, Eu²⁺/Eu³⁺ and Ce³⁺ activated Na₂Zn₅(PO₄)₄ has been synthesized by solid-state reaction technique at high temperature. X-ray powder diffraction analysis confirmed the formation of Na₂Zn₅(PO₄)₄ host lattice. Scanning electron microscopy indicated that the microstructure of the phosphor consisted of irregular fine grains with a size of about 0·5–2 μm. Photoluminescence excitation spectrum measurements of Ce³⁺ activated Na₂Zn₅(PO₄)₄ show that the phosphor can be efficiently excited by UV-Vis light from 280 to 310 nm to realize emission in the visible (blue) range due to the 5d-4f transition of Ce³⁺ ions which is applicable for scintillation purpose, whereas Eu²⁺/Eu³⁺ activated Na₂Zn₅(PO₄)₄ phosphor emits blue, green and red emission spectrum shows at 487 nm, 546 nm with a dominant peak at 611 nm respectively, due to Eu²⁺/Eu³⁺ ions which is promising candidate for solid state lighting. Therefore, newly synthesised, by low cost and easy technique prepared, novel phosphors may be useful as RGB phosphor for solid state lighting application.     

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.     

Temperature effect on the photoluminescence intensity and Eu<Superscript>2+</Superscript> excited state lifetime in EuGa<Subscript>2</Subscript>S<Subscript>4</Subscript> and EuGa<Subscript>2</Subscript>S<Subscript>4</Subscript>:Er<Superscript>3+</Superscript>

The photoluminescence (PL) spectra and Eu²⁺ excited state lifetime of EuGa₂S₄ and EuGa₂S₄:Er³⁺ have been studied in the range 78–500 K. The spectra show a band at 545 nm, due to the 4f ⁶5d → 4f ⁷(⁸ S _7/2) transition. With increasing temperature, the full width at half maximum Γ(T) of the PL band of EuGa₂S₄ and EuGa₂S₄:Er³⁺ crystals increases from 0.15 to 0.22 and from 0.13 to 0.19 eV, respectively. Over the entire temperature range studied, Γ(T) is a linear function of T ^1/2. The 545-nm emission intensity and Eu²⁺ excited state lifetime in EuGa₂S₄ and EuGa₂S₄:Er³⁺ vary exponentially with temperature. The luminescence quenching energies evaluated from the Arrhenius plots of I(10³/T) and τ(10³/T) coincide (0.10 eV) within the error of determination.     

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.     

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.     

Synthesis and photoluminescence study of narrow-band UVB-emitting LiSr<Subscript>4</Subscript>(BO<Subscript>3</Subscript>)<Subscript>3</Subscript>:Gd<Superscript>3+</Superscript>, Pr<Superscript>3+</Superscript> phosphor

A series of Pr³⁺, Gd³⁺ and Pr³⁺–Gd³⁺-doped inorganic borate phosphors LiSr₄(BO₃)₃ were successfully synthesized by a modified solid-state diffusion method. The crystal structures and the phase purities of samples were characterized by powder X-ray diffraction. Surface morphology of the sample was studied by scanning electronic microscopy (SEM). The optimal concentrations of dopant Gd³⁺ ions in compound LiSr₄(BO₃)₃ were determined through the measurements of photoluminescence (PL) spectra of phosphors. Gd³⁺-doped phosphors LiSr₄(BO₃)₃ show strong band absorption in UV spectral region and narrow-band UVB emission under the excitation of 276 nm was only due to ⁶P _J → ⁸S_7/2 transition of Gd³⁺ ions. The effect of Pr³⁺ ion on excitation of LiSr₄(BO₃)₃:Gd³⁺ was also studied. The excitation of LiSr₄(BO₃)₃:Gd³⁺, Pr³⁺ gives a broad-band spectra, which show very good overlap with the Hg 253.7 nm line. The photoluminescence spectra of LiSr₄(BO₃)₃ with different doping concentrations Pr³⁺ and keeping the concentration of Gd³⁺ constant at 0.03 mol have also been studied. The emission intensity of LiSr₄(BO₃)₃:Pr³⁺–Gd³⁺ phosphors increases with increasing Pr³⁺ doping concentration and reaches a maximum at 0.01 mol. From the photoluminescence study of LiSr₄(BO₃)₃:Gd³⁺, Pr³⁺ we conclude that there was efficient energy transfer from Pr³⁺→ Gd³⁺ ions in LiSr_4?x?y Pr _x Gd _y (BO₃)₃ phosphors.     

Phase conversion and spectral properties of long lasting phosphor Zn<Subscript>3</Subscript> (PO<Subscript>4</Subscript>)<Subscript>2</Subscript>:Mn<Superscript>2+</Superscript>, Ga<Superscript>3+</Superscript>

A red long lasting phosphor Zn₃(PO₄)₂:Mn²⁺,Ga³⁺ (ZPMG) was prepared by ceramic method, and phase conversion and spectral properties were investigated. Results indicated that the phase conversion from α-Zn₃(PO₄)₂, β-Zn₃(PO₄)₂ toγ-Zn₃(PO₄)₂ occurs with different manganese concentration incorporated and sinter process. The structural change induced by the phase transformation results in a remarkable difference in the spectral properties. The possible luminescence mechanism for this red LLP with different forms has been illustrated.     

Emission analysis of Pr<Superscript>3+</Superscript> &; Ho<Superscript>3+</Superscript>: Ca<Subscript>4</Subscript>GdO(BO<Subscript>3</Subscript>)<Subscript>3</Subscript> powder phosphors

Emission spectral results of Pr³⁺ & Ho³⁺ ions doped Ca₄GdO(BO₃)₃ powder phosphors are reported here. XRD, SEM and FTIR measurements have been carried out for them. The emission spectrum of Pr³⁺: Ca₄GdO(BO₃)₃ has shown an emission transition ¹D₂ → ³H₄ at 606 nm with λ_exci = 480 nm (³H₄ → ³P₀) and Ho³⁺: Ca₄GdO(BO₃)₃ phosphor has shown an emission transition ⁵S₂ → ⁵I₈ at 549 nm with λ_exci = 447 nm (⁵I₈ → ⁵F₁). Emission performances of these two phosphors have been explained in terms of energy level diagrams.     

Observation of an ultraviolet emission band in TiO<Subscript>2</Subscript> nanocrystals doped with Eu<Superscript>3+</Superscript>

The photoluminescence spectra of titanium dioxide (TiO₂) nanocrystals doped with Eu³⁺ (molar ratio Eu³⁺/TiO₂ = 0, 1, 2, 4%) are investigated under different excitation wavelengths. An ultraviolet band of emission energy higher than the energy gap is found for excitation wavelengths larger than 315 nm when the Eu³⁺ content is higher than 2%. The new emission band redshifts and its emission intensity is intensified with the increase of excitation wavelength. The emission mechanism for the new ultraviolet emission band is analyzed.     

Structure and luminescent properties of Cs<Subscript>2</Subscript>Sr(VO<Subscript>3</Subscript>)<Subscript>4</Subscript>:Mn<Superscript>2+</Superscript>

We have developed a procedure for thermally stimulated synthesis of a cesium strontium metavanadate, Cs₂Sr(VO₃)₄:Mn²⁺ (0.01, 0.50, 1.00, 5.00 at % Mn²⁺), using MnO-containing starting mixtures. The EPR spectrum of the material containing 0.01 at % Mn²⁺ shows a hyperfine structure due to the incorporation of a small amount of manganese into the diamagnetic double metavanadate host. The luminescent and optical properties of Cs₂Sr(VO₃)₄:Mn²⁺ depend on manganese content. In contrast to higher doping levels, doping with 0.01 at % Mn²⁺ increases the integrated emission intensity of the vanadate by 10% and improves its chromaticity characteristics (approaching them to those of white light). We assume that this is due to the reduction in the density of vacancy-type growth defects, such as oxygen vacancies.     

The comparison: photoluminescence and afterglow behavior in CaSnO<Subscript>3</Subscript>:Dy<Superscript>3+</Superscript> and Ca<Subscript>2</Subscript>SnO<Subscript>4</Subscript>:Dy<Superscript>3+</Superscript> phosphors

This paper reports the comparison of photoluminescence and afterglow behavior of Dy³⁺ in CaSnO₃ and Ca₂SnO₄ phosphors. The samples containing CaSnO₃ and Ca₂SnO₄ were prepared via solid-state reaction. The properties have been characterized and analyzed by utilizing X-ray diffraction (XRD), photoluminescence spectroscope (PLS), X-ray photoelectron spectroscopy (XPS), afterglow spectroscopy (AS) and thermal luminescence spectroscope (TLS). The emission spectra revealed that CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors showed different photoluminescence. The Ca₂SnO₄:Dy³⁺ phosphor showed a typical ⁴F_9/2 to ⁶H_j energy transition of Dy³⁺ ions, with three significant emissions centering around 482, 572 and 670 nm. However, the CaSnO₃:Dy³⁺ phosphor revealed a broad T₁ → S₀ transitions of Sn²⁺ ions. The XPS demonstrate the existence of Sn²⁺ ions in CaSnO₃ phosphor caused by the doping of Dy³⁺ ions. Both the CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors showed a typical triple-exponential afterglow when the UV source switched off. Thermal simulated luminescence study indicated that the persistent afterglow of CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the calcium stannate host with rare-earth ions (Dy³⁺).     

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⁺.