Effect Of Eu Research Articles

Effects of Eu3+ doping on the structural, magnetocaloric effect and critical behavior of Ruddlesden-Popper compounds La1.4-xEuxSr1.6Mn2O7 (0 ≤ x ≤ 0.1)

The effects of Eu3+ doping on the structural and magnetocaloric effect of Ruddlesden-Popper compounds La1.4-xEuxSr1.6Mn2O7 (0 ≤ x ≤ 0.1) were investigated. The X-ray diffraction and infrared spectroscopy confirmed that La1.4-xEuxSr1.6Mn2O7 compounds exhibited the tetragonal lattice symmetry (I4/mmm) of the Ruddlesden-Popper phase. The crystal structure of La1.4-xEuxSr1.6Mn2O7 compounds distorted and phase separated as the amount of Eu3+ doping varied. The magnetization-temperature curves demonstrated that La1.4-xEuxSr1.6Mn2O7 compounds display a notable transition temperature attributed to its anisotropic exchange coupling. The maximum magnetic entropy changes (−ΔSMmax) of La1.4-xEuxSr1.6Mn2O7(x = 0, 0.075, and 0.1) compounds are 2.82, 3.12 and 3.40 J/(kg·K) at the 5 T applied magnetic field. Meanwhile, its relative cooling power (RCP) was 186.37, 207.42 and 242.54 J/kg, respectively. The critical behavior of La1.4-xEuxSr1.6Mn2O7 (0≤x≤0.1) compounds was analyzed around Tc, and it was found that the critical index (β = 0.413, γ = 1.020, δ = 3.038) is essentially in line with the mean field theory.

Eu3+ doped Ca3LiSbO6 and Eu3+, Li+ co-doped Ca3LiSbO6 phosphors for white light-emitting diodes

Novel antimonate Ca3LiSbO6: xEu3+ red phosphor was synthesised using a high-temperature solid-phase reaction. The effect of Eu3+ doping concentration on its crystal structure and luminescence performance was investigated. It was found that Eu3+ was at the inversion symmetry site in the lattice of Ca3LiSbO6. To improve the luminescence performance of Ca3LiSbO6: 0.05Eu3+ red phosphor, Ca3LiSbO6: 0.05Eu3+, xLi + red phosphor was synthesised. The doping of Li + can correct the charge difference generated by the substitution of Ca2+ by Eu3+, reduce the generation of defects, enhance the local symmetry of the luminescence centre of Eu3+, improve the structural rigidity, and thus enhance the luminous intensity of the phosphor. At 423 K, the luminous intensity of this phosphor was 68 % of the initial temperature, which was higher than that of the phosphor without the charge compensator Li+ (60 %), indicating that Li+ improved the thermal stability of the phosphor.

Suppressing Self‐Oxidation of Eu2+ in Li2CaSiO4 for Full‐Spectrum Lighting and Accurate Temperature Sensing

AbstractEu2+‐doped phosphors have attracted the great attention of researchers in the past decade. However, Eu2+ dopant in inorganic hosts often suffers from the self‐oxidation effect, therefore causing the attenuated emission intensity and quantum efficiency. In this regard, developing Eu2+ doped phosphors with the prohibited self‐oxidation effect of Eu2+ and increased thermal stability is urgently required. Herein, an innovative cyan‐light emitting Li2CaSiO4:Eu2+/Eu3+, Lu3+ (LCSO) phosphor is designed. Both experimental results and theoretical calculations demonstrate that adding Lu3+ restricts the self‐oxidation of Eu2+ into Eu3+, thus improving the emission of Eu2+. Meanwhile, the Lu3+ introduction brings out excellent thermal stability. Finally, an efficient WLED with a color temperature (CCT) of 4573 K and a high color rendering index (Ra) of 84.2 is obtained using the as‐prepared phosphor due to the perfect compensation of the cyan light. As the introduction of Lu3+ improves the stability of Eu2+, a much greater difference in PL decay rate between Eu2+ and Eu3+ in LCSO is reached, thereby improving their sensitivity in temperature sensing. The strategy of Lu3+ introduction for prohibiting the self‐oxidation of Eu2+ for efficient and stable Eu2+ emission may stimulate some new ideas in designing high‐performance phosphors for more diverse applications.

Effect of Eu3+ ions concentration on visible red luminescence and radiative shielding properties of SrO–Al2O3– BaCl2–B2O3– TeO2 glasses

Trivalent europium (Eu3+) ions doped 10SrO-(10-x)Al2O3–10BaCl2–60B2O3–10TeO2 glasses were fabricated by the melt-and-quenching technique and characterized for excitation, absorption, emission, decay methods to analyze the suitability of the glasses for photonic device applications. In addition, gamma attenuation data of the prepared glasses were Obtained for energies 15 keV ≤ E ≤ 10 MeV using FLUKA and XCOM methods to check their suitability for radiative shielding purposes. Direct allowed, indirect allowed band gaps and Urbach energies were estimated from absorption spectra. Emission spectra obtained for an excitation wavelength of 362 nm have been used to estimate J-O intensity parameters Ωλ (where λ = 2, 4). The intensity parameters Ω2 and Ω4 were again used to evaluate various radiative properties for the emission transition 5D0→7F2 of Eu3+ ions doped OCBT glasses. Decay curves were well fitted by single exponential and in turn used to estimate experimental lifetime (τexp) of metastable state (5D0) of Eu3+ions. The analysis on radiative properties showed that 2.5 mol % of Eu3+ ions activated OCBT glasses for the emission transition 5D0→7F2 is well suitable for visible red lasers and display applications. Analysis of evaluated interaction parameters for gamma radiation fast and thermal neutrons showed clear cut dependence on the Eu2O3 content of the glasses. In addition, the radiation absorption ability of the glasses was compared with different classes of concrete, commercial glass shields, and nonconventional shielding materials. The present glasses showed great potential for deployment in radiation absorption roles in nuclear technologies.

Photoluminescence/cathodoluminescence properties and energy transfer mechanisms of fine-particle Gd2O2S:Tb3+, RE3+ (RE = Dy, Eu) phosphor

Gd2O2S:Tb3+, RE3+ (RE = Dy, Eu) phosphors were prepared by molten salt method and the samples were characterized by XRD, SEM, photoluminescence, cathodoluminescence and thermal stabilization. XRD results indicated that phosphors were pure hexagonal crystal structure and Dy3+ and Eu3+ sensitizers successfully occupied the Gd3+ sites. Granularity test results indicated that the average particle size of the powder was 2 μm. The effect of Eu3+ sensitizer on Tb3+ luminescence was discussed for the first time in the photoluminescence spectra. The results verified that the efficient emission of Tb3+ was sensitized by Dy3+/Eu3+ under the excitation of 288 nm/296 nm. 382 nm, 415 nm and 438 nm, which correspond to the 5D3 → 7FJ (J = 6, 5 and 4) of Tb3+, respectively, and 488 nm, 544 nm, 587 nm, 622 nm, which correspond to the 5D4 → 7FJ (J = 6, 5, 4 and 3) of Tb3+, respectively. There was also a weak emission peak of Dy3+ was seen at 576 nm (4F9/2 → 6H13/2) in Gd2O2S:Tb3+, Dy 3+. And weak emission peaks of Eu3+ were seen at 617 nm and 625 nm (5D0 → 7F2) in Gd2O2S:Tb3+, Eu 3+. The sensitizers of Dy3+ and Eu3+ not only effectively enhanced the photoluminescence of Tb3+ through electric quadrupole-electric quadrupole interactions and electric dipole-electric quadrupole interactions, respectively, but also effectively improved the thermal stability of Gd2O2S:Tb3+ through energy transfer. Increasing acceleration voltage could further enhance the powder's cathodoluminescence. Gd2O2S:Tb3+, Dy3+ phosphor had higher cathodoluminescence properties.

Effects of ion occupancy and polarizability on the crystal structure and microwave dielectric properties of CaEuCO4 (C[dbnd]Ga, Al) ceramics

CaEuCO4 (CGa, Al) microwave dielectric ceramics were produced through a solid-state reaction. Orthorhombic olivine CaEuGaO4 (pnma) exhibits a lower permittivity (εr = 9.7), a higher quality factor (Q × f = 82,049 GHz), and a larger negative resonant frequency temperature coefficient (τf = −54.6 ppm/°C). CaEuAlO4, which has a similar chemical formula, exhibits a perovskite-like structure (I4/mmm, K2NiF4-type), and its microwave dielectric properties are εr = 18.9, Q × f = 43,132 GHz, and τf = −1.6 ppm/°C. The difference in their structures is mainly caused by the properties of the Ga (III) atom. The difference in their dielectric properties can be proved to be affected by the “rattling” effect of Eu3+ through the bond valence theory. The relationship between the covalence (fc) and the bond strength (S) was investigated, and the higher bond strength might be the main reason for the higher Q × f in CaEuGaO4 ceramic.

Effect of Eu3+ and Sc3+ on the structure, microstructure and humidity sensing properties of copper ferrites for sensor applications

In this investigation, we studied the effect of rare lanthanides on the structure, microstructure, and humidity sensing characteristics of CuEuxScyFe(2-x)O4 ceramics with the following x = y values: 0.00, 0.01, 0.02, and 0.03. The preparation of the samples was accomplished through the utilization of the solution combustion method. The X-ray diffraction (XRD) patterns show the main cubic spinel crystal structure with the space group Fd3‾m with an additional second Fe2O3 phase. The estimated average spinel crystallite size varied from 25 to 10 nm across doping. The microstructure studied by scanning electron microscopy (SEM) proved the porous nature of CuEuxScyFe(2-x)O4 with agglomerated particles. The resistance and the humidity sensing responses become more evident for higher concentrations of Eu–Sc. As demonstrated by the hysteresis curves, the desorption process proceeds somewhat slower than the adsorption process. As recorded, the sensor response and recovery times were each clocked at 39 and 40 s, respectively.

Enhanced electric-field induced strain in Eu3+ doped 0.67BiFeO3-0.33BaTiO3 lead-free piezoelectric ceramics

Lead-free ferroelectric ceramics, 0.67Bi1–xEuxFeO3-0.33BaTiO3 (BF-BT-xEu, x = 0–0.02), were prepared via a solid-state reaction. The effect of Eu3+ doping on the microstructure, dielectric properties, ferroelectric properties, and electric-field-induced strain was investigated. The X-ray diffraction (XRD) results indicate the presence of a mixed phase of tetragonal and rhombohedral at the morphotropic phase boundary (MPB). Doping with an appropriate amount of Eu3+ reduces the Fe2+ content and decreases the leakage current in the binary system. A converse piezoelectric coefficient (d33∗) of 392 pm/V is obtained at BF-BT-0.003Eu under an electric field of 60 kV/cm at room temperature, which has a Curie temperature (TC) of 414 °C. The unipolar strain and d33∗ of BF-BT-0.003Eu ceramics increase to 0.438% and 730 pm/V at 125 °C. The field-induced strain response of the BF-BT-0.003Eu ceramics is greater than that of 0.67BF-0.33BT, mainly due to its optimal grain size, reduction of leakage current, and coexistence of ferroelectric-relaxation phases. BF-BT-0.003Eu ceramic is a lead-free candidate for high-temperature actuator applications.

Polarization-dependent orientation of LiNbO3:Eu3+ nanocrystals using ultrashort laser pulses in borosilicate glasses

Femtosecond (fs) laser writing is a flexible way to induce three-dimensional local structural modifications inside glass materials, such as crystallization. The latter is a function of both glass composition, hence properties, and laser parameters. Previous works have shown that a glass composition of 33Li2O–33Nb2O5–13SiO2–21B2O3 (LNSB) mol% yields to crystallization of laser polarization orientable LiNbO3 nanocrystals upon irradiation with a 1,030 nm fs laser. In this paper, we present the effects of rare earth incorporation in the glass composition [i.e., europium (0.5, 1, and 2 mol%)] on the crystallization process of LiNbO3 nanocrystals induced by fs laser irradiation. The embedding of Eu3+ ions into these nanostructures has an interest in developing new integrated and miniaturized optical lasers and amplifiers in visible wavelengths. The influence of laser parameters, such as repetition rate (RR), pulse energy, and polarization, has been studied. Irradiated areas are investigated using optical and electron microscopy techniques. The effect of Eu3+ concentration on the crystallization behavior (crystal formation and morphology) is discussed, as Eu2O3 is not acting as a nucleation agent in LNSB glass up to 2 mol%.

Effect of Eu3+ doping on structural, optical and magnetic characteristics of doped CdS nanoparticles

Hydrothermal method has been used to synthesize Cd1-xEuxS (x = 0, 0.01, 0.02 and 0.03) nanoparticles. With Eu-doping the changes in optical, magnetic and structural properties has been confirmed by UV–visible spectroscopy, PL, VSM and XRD. The X-ray diffraction confirmed wurtzite phase and peak shifting towards higher diffraction angle with Eu-doping can be ascribed to the smaller Eu3+ ion as compared to that of Cd2+ ion. The band gap enhances varying from 2.44 eV to 2.52 eV. The magnetic study proved the presence of ferromagnetism in both the samples i.e. undoped and doped synthesized nanoparticles with increment in magnetization. This study proposes that both the optical band gap and magnetic behavior shall be improved by suitable Eu-doping.

Computational and experimental investigation of Li+-ion transport mechanism of Eu-doped garnet solid electrolyte for Li-ion batteries

Garnet-type Li7La3Zr2O12 (LLZO) is one of the most preeminent solid electrolytes in all-solid-state lithium batteries (ASSLBs). To further improve the conductivity of LLZO, we synthesized a novel garnet-type solid electrolyte Li7+xLa3Zr2-xEuxO12 (0 ≤ x ≤ 0.20) in which the low-valence Eu+3 doped at the Zr+4 site. Using density functional theory (DFT) calculation, effect of Eu3+ doping was also investigated. Eu3+ doping normalized Li+-ion transport by enhancing Li+-ion occupancy at 96 h position which reduced the Li+-ion diffusion barrier and enhanced the ionic conductivity. Li7.15La3Zr1.85Eu0.15O12 (LLZEO) solid electrolyte exhibited highest ionic conductivity of 0.415 × 10−4 S/cm and the lowest activation energy of 0.28 eV at 25 °C. Further, a flexible composite electrolyte membrane was also prepared using LLZEO as filler into polyethylene oxide/polyethylene glycol matrix, which exhibited excellent flexibility and high ionic conductivity of 0.15 × 10−4 S/cm at 25 °C will be a promising candidate for ASSLBs.

The effects of Eu3+ doping on the piezoelectric property and temperature stability of the 0.15PSN-0.52PMN-0.33PT ceramics

We successfully prepared Eu2O3 doped 0.15PSN-0.52PMN-0.33PT ceramics through two-step solid state reaction, and carefully studied their phase structure, microstructure, electric performance and temperature stability. It is found that Eu3+ doped PSN-PMN-PT ceramics exhibit greatly improved piezoelectrical performance. When the Eu2O3 content is 0.02 mol, the ceramic shows the best synthetical properties: d33 = 859 pC/N, d33 * = 1078 pm/V, Ec= 5.18 kV/cm, and Tm = 139 °C. Compared with the undoped matrix ceramic, the d33 increases by nearly 78%, meanwhile, its variation rate is only 18% as the temperature rises from room temperature to 130 °C. Our results indicate that Eu3+ doped 0.15PSN-0.52PMN-0.33PT ceramics have promising candidate for practical applications.

Effect of Eu3+ doping on structural and optical properties of zirconium titanate

The Europium activated (1–9 mol %) Zirconium Titanate nanoparticles (NPs) have been synthesized by the green solution combustion method using Aloe Vera gel extract as a reducing agent, followed by the calcination at 720 °C for 3hrs. All the synthesized samples crystallize in a pure orthorhombic crystal structure with the space group of Pbcn. The surface and bulk morphology were analyzed. The crystallite size increases, whereas the direct energy band gap was found to decrease with an increase in dopant concentration. Further, the effect of dopant concentration on the photoluminescence properties was studied. The presence of Eu3+ ion in the trivalent state in the host lattice was confirmed by its characteristic emission at 610 nm due to 5D0→7F2 (λex = 464 nm). The CIE coordinates were found in the red region of the CIE 1931 diagram. The CCT coordinates lie in the range 6288–7125 K. The Judd-Ofelt parameters and derived quantities were analyzed. This theory confirms the high symmetry of Eu3+ ions in the host lattice. These findings imply that ZTO:Eu3+ can be employed as a nanopowder material in a red-emitting phosphor material.

Effects of Eu3+ concentration on the thermoluminescence properties of narrow-band red-emitting Eu3+: SrLaGaO4 phosphor

A series of Eu3+ doped SrLaGaO4 ceramic phosphors were successfully synthesized by the solid-state reaction method. The optical properties of (x at%) Eu: SrLaGaO4 samples with x = (0.1, 1, 3, 5, 10, 15, 20, 30) were investigated and analyzed. The room temperature emission spectra of xEu: SrLaGaO4 ceramic samples, under blue and UV excitation wavelengths, showed a maximum relative emission intensity at 620 nm, corresponding to the hypersensitive 5D0→7F2 transition, with a full width at half maximum (FWHM) of ∼7 nm, for a doping concentration with Eu3+ ions of 10 at% (x = 10). The asymmetry parameter (the ratio between the 5D0→7F2 and 5D0→7F1 transitions) and the critical distance between Eu3+ ions allowed to obtain a very good color purity of the red emission (88 %) for the 10Eu: SrLaGaO4 phosphor. The cross-relaxation and energy migration processes between Eu3+ ions in the 10Eu: SrLaGaO4 sample are negligible and do not contribute to the quenching of the 5D0 emitting level. From the investigation of the temperature-dependent luminescence intensity ratio (LIR) of the 5D0→7F2 and 5D0→7F1 transitions of the 10Eu: SrLaGaO4 sample in the range of 10–575 K, the relative sensitivity parameter (Sr) was found to be 0.4 % K−1 at 10 K and 0.45 % K−1 at 450 K. These results suggest that 10Eu: SLO phosphor is a versatile material that could be operated as a temperature sensor over a wide range of temperatures, as well as a narrow-band red-emitting phosphor for phosphor-converted white light-emitting diodes (pc-WLEDs).

The influence of Eu3+ doping on the optical and structural properties of the Ge2Y2O7 crystalline phase through a soft chemical process

The present work reports on the synthesis, structural and optical properties of Ge2Y2-xEuxO7 composition powders, with x ranging from 0.0 to 0.16 (from 0.0 to 4.0 mol% Eu3+). We synthesized stable and transparent sols, homogeneous gels, and powders treated at 1100 °C by a soft chemical route, and the effect of Eu3+ concentrations was evaluated. X-ray diffraction (XRD), infrared vibrational spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), emission and excitation photoluminescence spectroscopy (PL, PLE), decay curves of emission intensity as a function of time and quantum yield were obtained. An annealing temperature of 1100 °C was enough to obtain a single Ge2Y2O7 crystalline phase and the decrease of Χ2 value (from 2.32 to 1.74) with the increase of Eu3+ doping in the matrix, observed with the Rietveld refinement of the XRD patterns of the samples, is due to the crystallization process. Diffuse reflectance spectra and optical bandgap of 4.7 eV for Ge2Y0.88Eu0.12O7 (3.0 mol% Eu3+) – determined by Kubelka- Munk model – showed the good optical quality of the samples, which were considered non-conducting. All doped samples possessed visible photoluminescence emission from Eu3+ ions under excitation at 394 nm, with higher emissions occurring in the red region from 5D0 → 7F2 transition, with R/O relation equal to 2.6 and purity of red color higher than 85 % for the sample with x = 0.012. Analyzing photoluminescence emission spectra, the lifetime values and Judd-Ofelt parameters, we determined that Eu3+ occupied two different sites of the Ge2Y2O7 host matrix, replacing Y3+ ions, with the quenching concentration occurring between x = 0.12 and x = 0.16. The average decay lifetime of 5D0 level from Eu3+ was around 1.66 ms, with average quantum efficiency around of 48 % and an internal quantum yield equal to 7.17 %. Moreover, we evaluated their emission luminescence properties upon 394 nm excitation to explore for the first time the possibility of using this material in thermal sensing applications.

Structural, thermal and optical studies of Eu3+ ion doped Ge22As20Se58 glass

The effect of Eu3+ doping on improving the amorphous nature of commercial chalcogenide glass/ChG (Ge22As20Se58), which is typically used as a molded lens for mid-infrared imaging, has been investigated. The observed absence of bright spots in Transmission Electron Microscope-Selected area (electron) diffraction (TEM-SAED) pattern confirmed the doping-induced amorphous nature of Eu-Ge22As20Se58 glass. The thermal studies over glass transition temperature (Tg) using DSC technique also revealed that Eu doping has increased the amorphous nature along with the thermal stability of Ge22As20Se58 glass. The optical analysis using UV–vis absorption spectroscopy showed that the activity of Eu-doped ChG has been extended across the UV-visible region. Tauc plot derived band gap energy of Eu-doped and undoped ChG is found to be 2.2 and 2.6 eV, respectively.

Effect of Eu2+ and Tb2+ doping on structural, photoluminescence, thermodynamic and thermoelectric properties of celestine (SrSO4) phosphors

In this study, the density functional theory (DFT) based WIEN2K simulation code is used to calculate the ground state properties of [SrSO4]:Eu2+ and [SrSO4]:Tb2+ compounds with the help of FP-LAPW method. To determine the electrical and optical characteristics of Sr1-xAxSO4 (A = Eu2+, Tb2+), the Generalized gradient approximation with the addition of the Hubbard parameter (GGA + U) was utilized. The obtained band structure results of Sr1-xEuxSO4 compound show semiconducting nature (which is in the spin up (↑) state is 1.4eV while in the spin down (↓) state is 3.45eV), while the Sr1-xTbxSO4 compound depicts full-metallic nature through both spin states due to the crossing mechanisms of the conduction band minimum across the Fermi energy level. According to a theoretical assessment of optical properties, the compounds under investigation are promising possibilities for active optical devices working in the Ultra violet region. We have demonstrated in this work the variation of temperature (0–500 K) and pressure (0–10 GPa) on seven key thermodynamic parameters by Using quasi harmonic Debye model. The thermoelectric properties have been calculated in the temperature interval 500 K ≤ T ≤ 800 K by using the Boltzmann simulation code. The finding shows that Sr1-xEuxSO4 and Sr1-xTbxSO4 compounds are promising for future advanced optical and thermoelectric devices.

Effect of Eu3+ on the thermal degradation and luminescence properties of Sr2Si5N8: Eu phosphors

To be better applied in light emitting diodes (LEDs), phosphors are always required a good thermal stability. As an important factor which influences the thermal stability of the phosphors, thermal degradation is decided by the oxidation of the activated ions or the host. In this paper, the process of oxidation of Sr2Si5N8:Eu2+ were studied, as well as the influence of the production of Eu3+ on the stability of the phosphors. The results suggest that the oxidation process is directly related to the content of activated ions and the treated temperature. At the same time, the production of Eu3+ will promote Eu2+ further oxidation and reduce the thermal stability of the phosphors. On the other hand, an amorphous layer on the surface was found during the holding process, which has an inhibiting effect on the oxidation of the Eu2+.

Luminescent and magnetic behavior of Eu3+-doped lanthanum manganite after slow cooling

In this study, the effect of Eu3+ on the magnetic, optical, and structural behavior of the slow-cooled La0.7Sr0.3MnO3 and La0.4Eu0.3Sr0.3MnO3 manganites was investigated using magnetization measurements as a function of the applied field, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, FTIR measurements, and photoluminescence tests. The results showed that the addition of Eu3+ decreases the saturation magnetization of the manganite. An additional europium compound was identified after the slow cooling. The photoluminescence properties of this manganite showed to be dependent on the excitation wavelength, being more effective through the charge transfer band which transfers energy from the matrix to the Eu3+ ions. Two-lifetime constants were determined from photoluminescence experiments.

Effect of Eu3+, Bi3+, and Li+ doping on luminescent property of GdNbO4

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors, aiming at improving the Eu3+ emission by codoping of Bi3+ and Li+. Eu3+ singly doped, Eu3+ and Bi3+ doubly doped, and Eu3+, Bi3+, and Li+ triply doped GdNbO4 were prepared using a high-temperature solid-state reaction method. The red-orange emissions from Eu3+ in the singly doped samples are significantly improved by the codoping of Bi3+, mainly due to the energy transfer from Bi3+ to Eu3+. The additional codoping of Li+ is found to increase the Eu3+ emission significantly. This improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity. A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+ in GdNbO4 does not change significantly with the codoping of Bi3+ and Li+. Our results indicate that Li+ doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4 phosphors.