Eu3+ concentration dependent optical properties and energy transfer from host Gd3+ to Eu3+ in GdF3 nanocrystals

By using a hydrothermal method, a series of Eu³⁺ concentration dependent GdF₃ nanocrystals have been synthesized. The crystalline structures of samples are characterized by XRD patterns, the morphology and size of the samples are illustrated by FE-SEM images, and the optical properties of the samples are presented by PL excitation and emission spectra. The energy transfer from host Gd³⁺ to Eu³⁺ is observed in the Eu³⁺ doped GdF₃ nanocrystals. The optical properties of Eu³⁺ and the energy transfer efficiency from host Gd³⁺ to Eu³⁺ are discussed on the basis of the Eu³⁺ concentration dependent integrated PL excitation and emission spectra of Gd³⁺ and Eu³⁺. The discussion on optical properties of Eu³⁺ and the energy transfer from Gd³⁺ to Eu³⁺ is meaningful to design and synthesize Gd³⁺ based compounds.     

具有磁性-多色发光-热性能的MWCNTs负载NaGdF4:Tb3+,Eu3+多功能复合纳米材料

采用液相法成功制备了MWCNTs负载NaGdF₄:Tb³⁺,Eu³⁺纳米粒子的磁光热多功能复合纳米材料,并用XRD,SEM和EDS对其结构、组成和形貌进行了表征,结果表明:NaGdF₄:Tb³⁺,Eu³⁺纳米粒子为六方晶相,形貌为球形且尺寸分布均匀,直径大约为25 nm,并且均匀的包覆在MWCNTs的表面;通过PL,VSM和HTC对复合纳米材料的发光性能,磁性能和光热转换性能进行了表征,采用MTT法对多功能复合纳米材料的生物相容性进行了评估,结果表明:MWCNTs-NaGdF₄:Tb³⁺,Eu³⁺复合纳米材料具有良好的多色发光性能、磁性能、光热转换性能、低的毒性和良好的生物相容性。该种磁光热多功能复合纳米材料在生物标记、生物成像、肿瘤诊疗等领域有着广泛的应用前景。     

Homogeneous one-dimensional structured Tb(OH)3:Eu nanorods: Hydrothermal synthesis, energy transfer, and tunable luminescence properties

Nearly monodisperse, homogeneous and well-defined one-dimensional Tb_(1−x)(OH)₃:xEu³⁺ (x=0-3 mol%) nanorods have been prepared through hydrothermal method. The size of the Tb(OH)₃:Eu³⁺ rods could be modulated from nano- to micro-scale by using different amount of ammonia solution. They present highly crystallinity in spite of the moderate reaction temperature. Under ultraviolet excitation into the f→f transition of Tb³⁺ at 382 nm, Tb(OH)₃ samples show the characteristic emission of Tb³⁺ corresponding to ⁵D₄→⁷F_{6, 5, 4, 3} transitions; whereas Tb(OH)₃:Eu³⁺ samples mainly exhibit the characteristic emission of Eu³⁺ corresponding to ⁵D₀→⁷F_{1, 2, 4} transitions due to an efficient energy transfer occurs from Tb³⁺ to Eu³⁺. The increase of Eu³⁺ concentration leads to the increase of the energy transfer efficiency from Tb³⁺ to Eu³⁺. The PL colors of Tb(OH)₃:xEu³⁺ phosphors can be easily tuned from green, yellow, orange, to red by changing the doping concentration (x) of Eu³⁺.     

A Novel Synthesis of Alkaline Earth Silicate Phosphor Sr3MgSi2O8： Eu^2＋, Dy^3＋

A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8：Eu^2＋,Dy^3＋using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope （TEM）. The structure and optical properties of the phosphor powders were systematically investigated by means of X-ray diffraction and spectrofluorometry. TEM images have reflected the core-shell structure and quasi-spherical morphology of the precursor particles. It was found that the single-phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 ℃ for the samples prepared with the nano-coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid-state reaction in the comparable condition.     

CTAB-assisted hydrothermal synthesis of YVO4:Eu powders in a wide pH range

Rhombus-, rod-, soya bean- and aggregated soya bean-like YVO₄:Eu³⁺ micro- and nanostructures were synthesized by a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method at 180 °C for 24 h in a wide pH range. The as-synthesized powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). The XRD results confirmed the formation of phase-pure YVO₄:Eu³⁺ powders with tetragonal structure under hydrothermal process in a wide pH range. Electron microscopic observations evidenced the morphological transformation of YVO₄:Eu³⁺ powders from rhombus-like microstructure to rod-, soya bean, and aggregated soya bean-like nanostructures with an increase in the pH of the synthesis solution. The results from the PL measurements revealed that the intensities of PL emission peaks were significantly affected by the morphologies and crystallinity of samples due to the absence of an inversion symmetry at the Eu³⁺ lattice site, and the highest luminescence intensity was observed for rod-like YVO₄:Eu³⁺ powders.     

Improved luminescent behavior of YVO4:Eu3+ ceramic phosphors by Li contents

Crystalline phase and surface morphology of phosphors are important factors to determine luminescent characteristics. Li-doped YVO₄:Eu³⁺ ceramic samples were prepared by a solid state reaction method. The Li⁺ concentration was varied from 1 to 3 wt% to improve crystallinity and surface morphology of ceramics. Influence of Li doping on luminescent properties of YVO₄:Eu³⁺ ceramics has been investigated. Photoluminescence spectra have been measured at room temperature using a luminescence spectrometer and excitation by a broadband incoherent ultraviolet light source with an excitation wavelength of 325 nm. The emitted radiation was dominated by a red emission peak at 620 nm radiated from the ⁵D₀ → ⁷F₂ transition of Eu³⁺ ions. As Li⁺ ion content increases from 0 to 2 wt%, the photoluminescence (PL) brightness improved. The brightness of 2 wt% Li-doped YVO₄:Eu³⁺ ceramic was increased by a factor of 1.43 in comparison with that of YVO₄:Eu³⁺ ceramic. The enhanced luminescence resulted not only from the improved crystallinity but also from the enhanced surface roughness. The luminescent intensity and surface roughness exhibited similar behavior as a function of Li⁺ ion concentration.     

Synthesis and characterization of Eu-doped hydroxyapatite through a microwave assisted microemulsion process

Europium doped hydroxyapatite (Eu:HAp) nanosized particles with multiform morphologies have been successfully prepared via a simple microemulsion-mediated process assisted with microwave heating. The physicochemical properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra, and the kinetic decays, respectively. The results reveal that the obtained Eu:HAp particles are well assigned to the hexagonal lattice structure of the hydroxyapatite phase. Additionally, it is found that samples exhibit uniform morphologies which can be controlled by altering the pH values. Furthermore, the samples show the characteristic ⁵D₀–⁷F_1–4 emission lines of Eu³⁺ excited by UV radiation.     

Synthesis,characterization, and photoluminescence of SrBPO5:R,Na+ (R = Eu3+, Tb3+) phosphor for solid state lighting

A series of phosphors SrBPO₅:R,Na⁺ (R = Eu³⁺, Tb³⁺) were prepared by high-temperature solid-state synthesis, and their phase purity, morphology, IR spectra, and UV-Vis photoluminescence properties were investigated. The f-f transitions of Eu³⁺ and Tb³⁺ ions in the host lattice were assigned and discussed. The excitation and emission spectra indicate that SrBPO₅:Eu³⁺,Na⁺ and SrBPO₅:Tb³⁺,Na⁺ can be effectively excited by ultraviolet (394 and 370 nm), and exhibit reddish orange emission and yellowish green emission, respectively. The influence of the doping concentration on the relative emission intensity of Eu³⁺/Tb³⁺ was investigated, and the critical distance R_c was estimated in term of the concentration quenching data. The present study suggests SrBPO₅:R,Na⁺ (R = Eu³⁺, Tb³⁺) phosphor can be a potential candidate as an UV-convertible phosphor for white light-emitting diodes (LEDs).     

Nano/micro-scaled La(1,3,5-BTC)(H2O)6 coordination polymer: Facile morphology-controlled fabrication and color-tunable photoluminescence properties by co-doping Eu,Tb

Nano/micro-sized coordination polymer La(1,3,5-BTC)(H₂O)₆ with controllable morphologies have been successfully prepared on a large scale via a simple solution phase method at room temperature. By rationally adjusting the synthetic parameters such as concentration, molar ratio of reactants, surfactant, and solvent, the La(1,3,5-BTC)(H₂O)₆ with 3D flowerlike, wheatearlike, spherical, sheaflike, taillike, bundlelike hierarchical architectures, and 1D nanorods can be selectively prepared. More interestingly, the photoluminescence color of codoped Eu³⁺ and Tb³⁺ lanthanum 1,3,5-benzenetricarboxylate phosphors can be easily tuned from red, orange, yellow, green-yellow to green by changing co-doping concentration of activator ions, making the material has potential applications in building minioptoelectronic devices, biomedicine, and color display fields.     

SrCO3:Tb3+ hollow microspheres fabricated via solvothermal process and their optical properties

Well-dispersed SrCO₃:Tb³⁺ hollow microspheres have been synthesized in the water-ethanol-ethylene glycol solvent system using oleic acid (OA) as an additive without further annealing treatment. X-ray diffraction (XRD), fourier transform-infrared spectroscopy (FT–IR), and field emission scanning electron microscopy (FE-SEM), as well as photoluminescence spectroscopy (PL) were used to characterize the resulting samples. The dosage of OA and the reaction time play key roles in the formation of the final samples. The possible formation mechanism for SrCO₃:Tb³⁺ hollow microsphere is proposed. The SrCO₃:Tb³⁺ phosphors show strong photoluminescence with green emission ⁵D₄–⁷F₅ (544 nm) as the most prominent group under ultraviolet excitation, which have potential applications in field emission displays. The present synthesis process may be extended to fabricate other inorganic materials with special morphologies and functions.     

Synthesis and optical properties of BaTiO3:Eu3+@SiO2 glass ceramic nano particles

BaTiO₃:(5 %)Eu³⁺ nanoparticles and BaTiO₃:(5 %)Eu³⁺@SiO₂ composites were synthesized by the solvothermal method. The effects on the structure, morphology and luminescent properties were studied using samples with different molar ratios of BaTiO₃:(5 %)Eu³⁺@SiO₂: 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 08:92, 6.5:93.5, 05:95, and 1.5:98.5. When the amount of silica in the composites was increased, the orange emission of Eu³⁺ increased, too; this was observed by exciting the charge transfer band centered at 283 nm. Furthermore, an increase in the intensity of the emission was obtained under excitation at 394 nm as a consequence of the improvement in the crystallinity of the samples. The presence of silica and the degree of crystallinity of the samples were determined through the Fourier transform infrared spectra and X-ray diffraction patterns. All of the results suggest that our ceramic material could be a good candidate for biomedical applications such as biolabeling, since the luminescence of BaTiO₃:(5 %)Eu³⁺@SiO₂ composites have an emission intensity higher than that of nanoparticles composed solely of BaTiO₃:Eu³⁺. This work demonstrates that BaTiO₃:Eu³⁺@SiO₂ composites have an emission intensity higher than that of nanoparticles composed solely of BaTiO₃:Eu³⁺.     

Characterization and properties of Eu3+-doped CdWO4 prepared by a hydrothermal method

Eu³⁺-doped CdWO₄ was prepared for the first time by a hydrothermal method. The structure, morphology, and luminescence of the Eu³⁺-doped CdWO₄ were characterized. TEM results revealed that the pure CdWO₄ was a nanorod with a width of about 50 nm. The photoluminescent properties of Eu³⁺-doped CdWO₄ complexes indicated energy transfer from WO₄ ^2? groups to Eu³⁺ and suggested effective doping of Eu³⁺ into the lattice of CdWO₄. The photocatalytic activity of CdWO₄ and Eu³⁺-doped CdWO₄ was investigated by the photodegradation of methyl orange (MO). Eu³⁺-doped CdWO₄ had enhanced photocatalytic activity in the photodegradation of MO. The hydroxyl radical was detected by the terephthalic acid photoluminescence (TA-PL) method, and the regular change revealed that the hydroxyl radical may be the active species.     

Eu2+ & Mn2+‐Coactivated Ba3Gd(PO4)3 Orange‐Yellow‐Emitting Phosphor with Tunable Color Tone for UV‐Excited White LEDs

A novel orange‐yellow‐emitting Ba₃Gd(PO₄)₃:x Eu²⁺,y Mn²⁺ phosphor is prepared by high‐temperature solid‐state reaction. The crystal structure of Ba₃Gd(PO₄)₃:0.005 Eu²⁺,0.04 Mn²⁺ is determined by Rietveld refinement analysis on powder X‐ray diffraction data, which shows that the cations are disordered on a single crystallographic site and the oxygen atoms are distributed over two partially occupied sites. The photoluminescence excitation spectra show that the developed phosphor has an efficient broad absorption band ranging from 230 to 420 nm, perfectly matching the characteristic emission of UV‐light emitting diode (LED) chips. The emission spectra show that the obtained phosphors possess tunable color emissions from yellowish‐green through yellow and ultimately to reddish‐orange by simply adjusting the Mn²⁺ content (y) in Ba₃Gd(PO₄)₃:0.005 Eu²⁺,y Mn²⁺ host. The tunable color emissions origin from the change in intensity between the 4f–5d transitions in the Eu²⁺ ions and the ⁴T₁‐⁶A₁ transitions of the Mn²⁺ ions through the energy transfer from the Eu²⁺ to the Mn²⁺ ions. In addition, the mechanism of the energy transfer between the Eu²⁺ and Mn²⁺ ions are also studied in terms of the Inokuti–Hirayama theoretical model. The present results indicate that this novel orange‐yellow‐emitting phosphor can be used as a potential candidate for the application in white LEDs.     

Structure and spectroscopic properties of (Y,Eu)(PO3)3 polyphosphate red phosphors

A series of orange-red emitting phosphor Y(PO₃)₃: xEu³⁺ (x = 0.1–1.0) was prepared by a solid-state reaction route. The phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) as well as decay lifetimes. Studies revealed the phase transfer from monoclinic to orthorhombic when Y³⁺ is totally replaced by Eu³⁺, and expansion of the unit cell occurs with increasing Eu³⁺ doped content. The PL spectra show that the phosphors Y(PO₃)₃: xEu³⁺ can be effectively excited by near ultraviolet (n-UV) light, and exhibit strong red-orange emission with no concentration quenching. The profile of PL spectra changes significantly at high Eu³⁺ content (x ≥ 0.80), which is due to the variation of preference for substitution of Eu³⁺. The luminescence due to the ⁵D₀ → ⁷F_J (J = 1, 2) transitions at 77 K exhibits its own spectral features for different crystallographic site. It is found that Eu³⁺ ions occupy the centers of octahedral polyhedron and form C_i/C₁ point group in Y(PO₃)₃.     

A template-free solvothermal synthesis and photoluminescence properties of multicolor Gd2O2S:xTb3+, yEu3+ hollow spheres

The multicolor Gd₂O₂S:xTb³⁺, yEu³⁺ hollow spheres were successfully synthesized via a template-free solvothermal route without the use of surfactant from commercially available Ln (NO₃)₃·6H₂O (Ln = Gd, Tb and Eu), absolute ethanol, ethanediamine and sublimed sulfur as the starting materials. The phase, structure, particle morphology and photoluminescence (PL) properties of the as-obtained products were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and photoluminescence spectra. The influence of synthetic time on phase, structure and morphology was systematically investigated and discussed. The possible formation mechanism depending on synthetic time t for the Gd₂O₂S phase has been presented. These results demonstrate that the Gd₂O₂S hollow spheres could be obtained under optimal condition, namely solvothermal temperature T = 220 °C and synthetic time t = 16 h. The as-obtained Gd₂O₂S sample possesses hollow sphere structure, which has a typical size of about 2.5 μm in diameter and about 0.5 μm in shell thickness. PL spectroscopy reveals that the strongest emission peak for the Gd₂O₂S:xTb³⁺ and the Gd₂O₂S:yEu³⁺ samples is located at 545 nm and 628 nm, corresponding to ⁵D₄→⁷F₅ transitions of Tb³⁺ ions and ⁵D₀→⁷F₂ transitions of Eu³⁺ ions, respectively. The quenching concentration of Tb³⁺ ions and Eu³⁺ ions is 7%. In the case of Tb³⁺ and Eu³⁺ co-doped samples, when the concentration of Tb³⁺ or Eu³⁺ ions is 7%, the optimum concentration of Eu³⁺ or Tb³⁺ ions is determined to be 1%. Under 254 nm ultraviolet (UV) light excitation, the Gd₂O₂S:7%Tb³⁺, the Gd₂O₂S:7%Tb³⁺,1%Eu³⁺ and the Gd₂O₂S:7%Eu³⁺ samples give green, yellow and red light emissions, respectively. And the corresponding CIE coordinates vary from (0.3513, 0.5615), (0.4120, 0.4588) to (0.5868, 0.3023), which is also well consistent with their luminous photographs.     

Hydrothermal homogeneous urea precipitation of hexagonal YBO3:Eu nanocrystals with improved luminescent properties

Well-crystallized YBO₃:Eu³⁺ nanocrystals were prepared by a mild hydrothermal method in the presence of urea, and a pure hexagonal phase could be obtained at a low temperature of 200°C only. The photoluminescence spectra showed a remarkable improvement on the chromaticity as well as the luminescent intensity, compared with the samples synthesized by solid-state reaction (SR). The effects of the synthesis temperature, urea concentration, and the doping concentration of Eu³⁺ on the crystallization and luminescent properties were investigated. The results showed that both high temperature and low urea concentration were favorable to the formation of YBO₃:Eu³⁺, and the ratio of red emission (⁵D₀→⁷F₂) to orange emission (⁵D₀→⁷F₁) increased with decreasing the synthesis temperature and the urea concentration. Furthermore, the samples exhibited a higher quenching concentration of Eu³⁺ in comparison with those prepared by the SR, which was beneficial to further enhancing the luminescent intensity. These synthesis-dependent phenomena were analyzed, and possible explanations were proposed.     

Solvothermal synthesis and luminescent properties of monodisperse LaPO4:Ln (Ln=Eu, Ce, Tb) particles

Monodisperse rare-earth ion (Eu³⁺, Ce³⁺, Tb³⁺) doped LaPO₄ particles with oval morphology were successfully prepared through a facile solvothermal process without further heat treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the kinetic decays were performed to characterize these samples. The XRD results reveal that all the doped samples are well crystalline at 180 °C and assigned to the monoclinic monazite-type structure of the LaPO₄ phase. It has been shown that all the as-synthesized samples show perfectly oval morphology with narrow size distribution. The possible growth mechanism of the LaPO₄:Ln has been investigated as well. Upon excitation by ultraviolet radiation, the LaPO₄:Eu³⁺ phosphors show the characteristic ⁵D₀−⁷F_1-4 emission lines of Eu³⁺, while the LaPO₄:Ce³⁺, Tb³⁺ phosphors demonstrate the characteristic ⁵D₄−⁷F_3-6 emission lines of Tb³⁺.     

Controlled synthesis and luminescent properties of Eu(Eu), Dy-doped Sr3Al2O6 phosphors by hydrothermal treatment and postannealing approach

In this work, Sr₃Al₂O₆: Eu²⁺ (Eu³⁺), Dy³⁺ phosphors have been prepared by hydrothermal treatment and subsequently postannealing approach, using Sr(NO₃)₂, Al(NO₃)₃·9H₂O, and CO(NH₂)₂ as starting materials. The as-obtained phosphors were characterized by means of XRPD, FESEM, and PL techniques. In addition, many reaction parameters were studied in detail, including the initial mole ratios, hydrothermal reaction temperature, calcination temperature and calcination atmosphere. Remarkably, two scientific merits exist herein: Sr₃Al₂O₆: Eu²⁺ (Eu³⁺), Dy³⁺ phosphors can be selectively obtained in a reducing atmosphere (H₂/Ar, 20%+80%) and in air, respectively; adding certain amount of sodium citrate can alter the shape and size of Sr₃Al₂O₆: Eu²⁺ (Eu³⁺), Dy³⁺ phosphors in essence. Besides, the luminescent properties of Sr₃Al₂O₆: Eu²⁺ (Eu³⁺), Dy³⁺ phosphors were studied by excitation spectra, emission spectra and decay curves.     

Uniform AMoO4:Ln (A=Sr, Ba; Ln=Eu, Tb) submicron particles: Solvothermal synthesis and luminescent properties

Rare-earth ions (Eu³⁺, Tb³⁺) doped AMoO₄ (A=Sr, Ba) particles with uniform morphologies were successfully prepared through a facile solvothermal process using ethylene glycol (EG) as protecting agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the kinetic decays were performed to characterize these samples. The XRD results reveal that all the doped samples are of high purity and crystallinity and assigned to the tetragonal scheelite-type structure of the AMoO₄ phase. It has been shown that the as-synthesized SrMoO₄:Ln and BaMoO₄:Ln samples show respective uniform peanut-like and oval morphologies with narrow size distribution. The possible growth process of the AMoO₄:Ln has been investigated in detail. The EG/H₂O volume ratio, reaction temperature and time have obvious effect on the morphologies and sizes of the as-synthesized products. Upon excitation by ultraviolet radiation, the AMoO₄:Eu³⁺ phosphors show the characteristic ⁵D₀–⁷F_1–4 emission lines of Eu³⁺, while the AMoO₄:Tb³⁺ phosphors exhibit the characteristic ⁵D₄–⁷F_3–6 emission lines of Tb³⁺. These phosphors exhibit potential applications in the fields of fluorescent lamps and light emitting diodes (LEDs).     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.