Low Site Symmetry Research Articles

Eigenstate analysis of the crystal electric field at low-symmetry sites: Application for an orthogonal site in the tetragonal crystal Ce2Pd2Pb

We have established an analyzing method to determine eigenstates of $4f$ electrons under the crystal electric field (CEF) at low-symmetry sites. This analysis requires macroscopic physical properties only, namely the saturation moments along several symmetrical directions of the crystal in addition to the magnetic susceptibility and specific heat, instead of the spectrum of the inelastic neutron scattering frequently used for such a complicated circumstance. As a successful case, the eigenstates of a CEF Hamiltonian under an orthogonal point group ${C}_{2v}$ are determined for the $J=\frac{5}{2}$ state of the cerium ion in a tetragonal compound ${\mathrm{Ce}}_{2}{\mathrm{Pd}}_{2}\mathrm{Pb}$. During the analysis, an angular momentum operator along the arbitrary direction is deduced from the space rotation operator. A matrix representation of the projection operator that transforms the basis of wave functions from $|{J}_{z}\ensuremath{\rangle}$ to $|{J}_{x}\ensuremath{\rangle}$ or $|{J}_{y}\ensuremath{\rangle}$ is also shown for $J=\frac{5}{2}$. This analysis reveals the anisotropic moments within highly symmetrical structures, and will contribute to understanding anisotropic field responses in rare-earth compounds.

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)-aliphatic dicarboxylates at room temperature.

Complexation of actinides and lanthanides with carboxylic organic ligands is a critical issue affecting radionuclide migration from deep geological disposal systems of spent nuclear fuel. A series of Eu(iii)–aliphatic dicarboxylate compounds, as chemical analogs of radioactive Am(iii) species, Eu2(Ox)3(H2O)6, Eu2(Mal)3(H2O)6, and Eu2(Suc)3(H2O)2, were synthesized and characterized using X-ray crystallography and time-resolved laser fluorescence spectroscopy to examine the ligand-dependent binding modes and the corresponding changes in spectroscopic properties. Powder X-ray crystallography results confirmed that all of the compounds presented a crystalline polymer structure with a trigonal prism square-face tricapped polyhedron geometry centered on Eu(iii) in a nine-coordinate environment involving nine oxygen atoms. This study captures the transition of the coordination modes of aliphatic dicarboxylate ligands from side-on to end-on binding as the carbon chain length increases. This transition is illustrated in malonate bindings involving a combination of side-on and end-on modes. Strongly enhanced luminescence, especially for the hypersensitive peak, indicates a low site symmetry in the formation of solid compounds. The number of remaining bound water molecules was estimated from the resultant increased luminescence lifetimes, which were in good agreement with crystal structures. The excitation–emission matrix spectra of these crystalline polymers suggest that Ox ligands promote the sensitized luminescence of Eu(iii), especially in the UV region. In the case of Mal and Suc ligands, charge transfer occurs in the opposite direction from Eu(iii) to the ligands under UV excitation, resulting in weaker luminescence.

Crystal-phase-specific near-infrared photoluminescence from Er3+-doped Bi2O3 thin films

Er3+-doped Bi2O3 films were sputter deposited on Si(100) substrates at room temperature with H2O vapor as an oxygen source gas. Crystal phases appearing after postannealing in an O2 atmosphere included single-phases of α-Bi2O3, γ-Bi2O3, and δ-Bi2O3, as well as a mixed phase of α-Bi2O3 and γ-Bi2O3. Selection of the crystal phase was possible in terms of H2O pressure and postannealing temperature. Photoluminescence spectra from Er3+ ions excited at a laser wavelength of 532 nm revealed distinct spectral features specific to the crystal phases. A clear crystal-field splitting feature consisting of eight emission lines was observed in PL spectra from sufficiently oxidized α-Bi2O3:Er films, indicating that Er3+ ions occupied low-symmetry C2v sites of Bi3+. The optimum annealing temperature for optical activation of Er3+ ions was between 400 and 450 °C. The emission intensity of α-Bi2O3:Er deposited with H2O was seven times higher than that of α-Bi2O3:Er deposited with O2 probably because larger numbers of Er3+ could substitute Bi3+ sites under reduced condition. Increasing deposition temperature lowered the emission intensity due to the loss of OH and H species from the as-deposited films. The emission spectra of γ-Bi2O3:Er were featureless and its emission intensity was one order of magnitude lower than that of α-Bi2O3:Er. The low-temperature phase of δ-Bi2O3:Er turned out to be entirely emission inactive. Reactions at the interface between the Bi2O3 film and the Si substrate were promoted upon postannealing at 500 °C. The resulting Bi2SiO5:Er exhibited a weak emission spectrum with four emission lines, which reflected occupation at tetragonal Bi3+ sites in the (Bi2O2)2− layers.

Polarized spectroscopy of electric and magnetic dipole transitions of Europium (III) ions in C2 sites

Polarization anisotropy of luminescent properties of europium (III) ions in low-symmetry C2 sites is studied using monoclinic (sp. gr. C2/c) tungstate crystal KY(WO4)2. The 5D0 → 7FJ (where J = 0…6) transitions are characterized for the principal light polarizations. Polarization selection rules for the magnetic dipole 5D0 → 7F1 transition are presented. The stimulated-emission cross-sections for Eu3+ ions relevant for laser operation are determined.

Spin resonance amplitude and frequency of a single atom on a surface in a vector magnetic field

We used electron spin resonance (ESR) combined with scanning tunneling microscopy (STM) to measure hydrogenated Ti (spin-1/2) atoms at low-symmetry binding sites on MgO in vector magnetic fields. We found strongly anisotropic g-values in all three spatial directions. Interestingly, the amplitude and lineshape of the ESR signals are also strongly dependent on the angle of the field. We conclude that the Ti spin is aligned along the magnetic field, while the tip spin follows its strong magnetic anisotropy. Our results show the interplay between the tip and surface spins in determining the ESR signals and highlight the precision of ESR-STM to identify the single atom's spin states.

Spectroscopic and Structural Properties of β-Tricalcium Phosphates Ca9RE(PO4)7 (RE = Nd, Gd, Dy)

Rare-earth-based Ca9RE(PO4)7 (RE = Nd, Gd, Dy) materials were synthesized by solid-state reaction at T = 1200 °C. The obtained tricalcium phosphate (TCP) materials are efficient light emitters due to the presence of RE3+ ions, although these ions are present at high concentrations. Moreover, in these host structures, these ions can be used as optical probes to study their local environments. Thus, photoluminescence (PL) emission spectra of the powder samples clearly indicated, for Dy3+ and Gd3+ ions, the presence of the RE3+ ion in low-symmetry sites with some local structural disorder, and the spectra show the presence of vibrational features (in the case of Gd3+). For the Nd3+ phase, emission bands are present around 900, 1050, and 1330 nm, originating from the 4F3/2 level. In general, these RE-TCP samples are interesting luminescent materials in the visible (Dy), UV (Gd), and NIR (Nd) regions, due to weak concentration quenching even for high concentrations of the emitting ion.

Effects of Sc3+ ions on local crystal structure and up-conversion luminescence of layered perovskite NaYTiO4: Yb3+/Er3+

This work focused on influences of Sc3+ dopants on local site symmetry and ligand field of Er3+ activators as well as its up-conversion luminescence performances sensitized by Yb3+ ions in NYTiO4 (NYT). The structure analysis and Judd-Ofelt calculation confirmed that doping Sc3+ ions could lower site symmetry as well changed the ligand field around Er3+ ions. The introduction of Sc3+ ions induced variations of crystal lattices, regulated distances between Er3+ions and Er3+ or Yb3+ ions, and thus influenced the up-conversion luminescence properties. Besides, time-resolved decay curves figured out the great enhancement of lifetime and luminescence quantum efficiency for both green and red emissions due to Sc3+ dopants. For optical temperature sensitivity, thermally coupled levels (TCLs) for blue emission 4F5/2/4F7/2→4I15/2 was studied for the first time. Besides, TCLs for violet emission 4G11/2/2H9/2→4I15/2 as well as green emission 2H11/2/4S3/2→4I15/2 were also recorded. By tri-doping Sc3+ ions into NYT: Yb/Er, both absolute sensitivity and relative sensitivity of above three TCLs were improved with temperature uncertainty decreasing.

Optical Spectroscopy of Li6Y(BO3)3 Single Crystals Doped with Dysprosium

The energy levels of Dy3+ ions have been determined in lithium yttrium borate (Li6Y(BO3)3) single crystals in a wide spectral range between 3000 and 40,000 cm−1 using optical absorption and luminescence spectroscopy, which also allow for an analysis of the ground state. The crystal field splittings of the 6H15/2 ground state and all excited states up to the 4F7/2 manifold were obtained at a low temperature, based on luminescence (T = 4.2–78 K) and absorption (T = 8–100 K) measurements, respectively. The numbers of experimentally observed Stark sublevels are in agreement with those expected theoretically for Dy3+ ions occupying a single low symmetry (C1) site.

Structural design enables highly-efficient green emission with preferable blue light excitation from zero-dimensional manganese (II) hybrids

• Two new zero-dimensional Mn 2+ bromide hybrids are reported. • Both show preferable blue light excitation and high photoluminescence efficiency. • The orbital-mixing for Mn-Br bond play a significant role. • A WLED with ~130 lm/W and superb long-term stability is achieved. Manganese (II) compounds are promising luminescent candidates for white light-emitting diodes (WLEDs) applications. However, the forbidden d - d transition of Mn 2+ ion makes the absorption of blue light and emission relatively weak without a sensitizer. The strategy of isolating MnX n (X is the ligand) with some ionic liquids is used to design two new hybrid compounds in this study, focusing on the orbital hybridization to relax the parity selection rule of the d - d transition. A large hindrance of the organic cations in the two new Manganese (II) hybrids enables a large Mn-Mn distance (up to ~ 10 Å) to form zero-dimensional (0D) structures, and the Mn sites in both compounds have a low site symmetry ( C 2 or C 1 ). The 0D structure of MnX n polyhedral is beneficial to isolatedly investigate the orbital hybridization of the ligand and Mn 2+ ion. A higher orbital hybridization extent for Mn-Br bond is evidenced by Density Functional Theory (DFT) simulation. This conclusion leads to the strong and stable green light emissions under preferable blue light (460 nm) excitations, giving photoluminescence quantum yields (PLQYs) as high as 76%. The WLEDs fabricated with these compounds have presented high luminous efficiency up to ~130 lm/W and survived multiple stability tests. The research favors the discovery of ideal Mn compounds for displays and lighting applications.

Tricolor Ho^{3+} Photoluminescence Enhancement from Site Symmetry Breakdown in Pyrochlore Ho_{2}Sn_{2}O_{7} after Pressure Treatment.

The photoluminescence (PL) characterization spectrum has been widely used to study the electronic energy levels. Ho^{3+} is one of the commonly used doping elements to provide the PL with concentration limited to 1% atomic ratio. Here, we present a tricolor PL achieved in pyrochlore Ho_{2}Sn_{2}O_{7} through pressure treatment at room temperature, which makes a non-PL material to a strong multiband PL material with Ho^{3+} at the regular lattice site with 18.2% concentration. Under a high pressure compression-decompression treatment up to 78.0GPa, the Ho_{2}Sn_{2}O_{7} undergoes pyrochlore (Fd 3m), to cotunnite (Pnma), then amorphous phase transition with different Ho^{3+} coordinations and site symmetries. The PL emerged from 31.2GPa when the pyrochlore to cotunnite phase transition took place with the breakdown of site symmetry and enhanced hybridization of Ho^{3+} 4f and 5d orbitals. Upon decompression, the materials became an amorphous state with a partial retaining of the defected cotunnite phase, accompanied with a large enhancement of red-dominant tricolor PL from the ion pair cross-relaxation effect in the low-symmetry (C_{1}) site, in which two distinct Ho^{3+} emission centers (S center and L center) are present.

Influence of temperature on near-infrared luminescence, energy transfer mechanism and the temperature sensing ability of La2MgTiO6: Nd3+ double perovskites

La2MgTiO6: Nd3+ samples synthesized by the coprecipitation method crystallized in an orthorhombic phase with space-group Pbnm (62). The SEM images of the sample showed heterogeneous morphology and the average crystallite size was 0.7 μm. Luminescent spectra, typical for Nd3+ ions at low symmetry site (Cs), were observed in all samples excited at 266 nm and 808 nm. The highest emission intensity was obtained for the sample doped with 3% Nd3+. The emission lifetimes at 77 K and 300 K shorten with increasing Nd3+ concentration due to cross-relaxation processes. Noticeably, the lengthening of the decay times at 300 K, as compared to 77 K, resulted from the thermalization of the higher Stark component of the 4F3/2 level. In addition, the experimental data were analysed using the Inokuti – Hirayama model; the energy transfer between Nd3+ ions was predominantly regulated by the dipole–dipole interaction. The critical transfer distance R0, critical concentration C0, energy transfer parameter Cda, and energy transfer probability Wda were found to be 4.9 Å, 2×1021 ions∙cm−3, 5.67×10-41 cm6∙s-1, and 4004 s-1, respectively. Furthermore, the temperature–dependent luminescence exhibited good thermal stability with temperature quenching at 450 K. The temperature sensing ability of the sample doped with 5 % Nd3+, based on the emission of two thermally coupled 4F5/2 and 4F3/2 levels, was investigated. The highest value of the relative sensitivity was 0.81 and 0.83 % K-1 at 248 K and 275 K, respectively.

Highly efficient Eu3+-activated Ca2Gd8Si6O26 red-emitting phosphors: A bifunctional platform towards white light-emitting diode and ratiometric optical thermometer applications

To fulfill bifunctional applications of the white light-emitting diode (white-LED) and optical thermometry, Eu3+-activated Ca2Gd8Si6O26 phosphors were prepared. Upon 394 nm excitation, dazzling red emission with admirable color purity of 93.8% was seen and the optimal doping content of the Eu3+ ions in the Ca2Gd8Si6O26 host was 30 mol%. The Ca2Gd8Si6O26:2.4Eu3+ phosphors showed a high quantum efficiency of 53.9%. Via investigation of the relation between the dopant content and emission intensity, one knows that the concentration quenching mechanism was decided by electric dipole-dipole interaction. Though estimating the values of Ω2 and Ω4 based on the Judd-Ofelt theory, it was proved that the Eu3+ ions took the low symmetry sites in the Ca2Gd8Si6O26 host lattices. Furthermore, the temperature-dependent emission spectra manifested that the resultant compounds had splendid thermal stability with activation energy of 0.25 eV. Utilizing the prepared compounds as the red-emitting components, a white-LED was packaged and it can emit high quality white light with high color rendering index (84.8) and low correlated color temperature (4981 K). Additionally, through analyzing the temperature-dependent excitation spectrum, the optical thermometric behaviors of the designed phosphors were studied. The maximum absolute and relative sensitivities of the studied compounds were 0.0014 K-1 and 0.276% K−1, respectively. These results provided a new insight into searching for novel bifunctional luminescent materials towards white-LED and ratiometric optical thermometer applications.

Luminescence performance of yttrium-stabilized zirconia ceramics doped with Eu3+ ions fabricated by Spark Plasma Sintering technique

Yttrium stabilized zirconia (YSZ) ceramics doped with Eu3+ ions have been successfully fabricated by Spark Plasma Sintering (SPS) technique. The influence of the europium concentration and post-annealing process on the structural, optical, and luminescent properties of the ceramics has been studied. It is shown that an increase in the europium concentration from 0.1 to 3 wt% does not lead to significant changes in the transmission spectra. However, annealing in air atmosphere at temperature from 700 °C to 1300 °C significantly affects the transmission spectrum, as a possible consequenceofthe formation of oxygen vacancy defects. The analysis of the photoexcitation and photoluminescence spectra showed that the main excitation bands are determined by direct excitation of the 7F0 ground state of Eu3+ions to the higher 4f energy levels with further radiation transitionsfrom these states. Moreover, the europium ion in the obtained ceramics occupy low-symmetry sites without inversion center.The luminescence decay kineticsare described by a doubleexponential function with decay time τ1 ~ 20 ns and τ2~ 90 ns for intrinsic emission centers and millisecond (τ ~ 1.4 ms) for Eu3+emission, for all investigated ceramics. The luminescence spectra in nanosecond time region are characteristic for yttrium-stabilized zirconia and are caused by oxygen vacancies in the presence of heavy cations (Y3+ and Eu3+).

Red luminescence with controlled rise time in La2MgTiO6: Eu3+

La2MgTiO6 (LMT) doped with Eu3+ ions has been prepared for the first time by the co-precipitation method. All samples crystallize in the same orthorhombic crystal structure and the unit cell volume decreases with increasing dopant concentration.The Eu3+ luminescence can be excited either into O2− → Eu3+ Charge Transfer State (CTS) with a maximum at 320 nm or into 4f levels and exhibits the emission spectrum characteristic for Eu3+ ions at the low symmetry site. TiO6 groups are also optically active with absorption at 305 nm and a weak broadband emission at 478 nm. The configurational coordinate diagram was constructed based on the absorption, emission and thermal quenching energy values. The relative thermal sensitivity of the intensity ratio between luminescence excited at 532 nm and 266 nm is above 1% for temperatures below 230 K and 3% for 77 K.The rise time of the 5D0 luminescence after the pulse excitation of the 5D1, resulting from both the multiphonon relaxation and the cross-relaxation, strongly depends on the Eu3+ concentration and goes from 94.1 μs for 0.1% Eu3+ down to 39.6 μs for 7% Eu3+. It is only observed when the sample is excited at 532 nm (into the 5D1 level). When the sample is excited into the CTS, the rise time is not observed.

Convenient Route to Heterometallic Group 4-Zinc Precursors for Binary Oxide Nanomaterials.

In this study, simple and efficient synthetic routes to a family of uncommon group 4-zinc heterometallic alkoxides were developed. Single-source molecular precursors with the structures [Cp2TiZn(μ,η-OR)(THF)Cl2] (1), [Zr3Zn7(μ3-O)(μ3,η2-OR)3(μ-OH)3(μ,η2-OR)6(μ,η-OR)6Cl6] (2), and [Hf3Zn7(μ3-O)(μ3,η2-OR)3(μ-OH)3(μ,η2-OR)6(μ,η-OR)6Cl6] (3) were prepared via reduction of Cp2TiCl2 with metallic zinc or protonolysis of the metal-cyclopentadienyl bond in Cp2M'Cl2 (M' = Zr or Hf) in the presence of 2-methoxyethanol (ROH) and Zn(OR)2. This synthetic route enables the creation of compounds with well-defined molecular structures and therefore provides precursors suitable for obtaining group 4-zinc oxides. Precursors 1-3 were characterized by elemental analysis, nuclear magnetic resonance and infrared spectroscopies, and single-crystal X-ray diffraction. Compound 1 decomposed at 800-900 °C to give a mixture of binary metal oxides (i.e., Zn2Ti3O8, ZnTiO3, or Zn2TiO4) and common polymorphs of TiO2 and ZnO. After calcination at 1000 °C, only TiO2 and the high-temperature-stable phase Zn2TiO4 were observed. Thermolysis of compounds 2 and 3 gave mixtures of ZnO and ZrO2 or HfO2, respectively. The obtained ZnO-ZrO2 and ZnO-HfO2 mixed oxide materials have constant phase compositions across a broad temperature range and therefore are attractive host lattices for Eu3+ for applications as yellow/red double-light-emitting phosphors. It was established that Eu3+ ions were successfully introduced into the ZnO and ZrO2/HfO2 lattices. It was revealed that Eu3+ ions prefer to occupy low-symmetry sites in ZrO2/HfO2 rather than in ZnO.

Effects of Li addition on the luminescent properties of LiSrPO4:Eu3+ excited with X-ray and ultraviolet radiation

Abstract Li1+xSr0.99PO4:Eu0.01 (x = 0.1, 0.3 or 0.5) phosphors are prepared using glucose with a modified sol-gel method. X-ray diffraction (XRD), scanning electron microscopy and photoluminescence and X-ray absorption spectroscopy are used to characterize the structural and optical behaviour of the phosphors. LSPOE powders have been successfully synthesized by sol-gel route and confirmed by XRD. A variation in lithium stoichiometry does not contribute to significant changes in structural properties, as probed by XRD. The samples have a partially spherical morphology with a high degree of particle agglomeration. The emission intensity of Eu3+ varies with the increase in Li+ content, in agreement with the variation of the symmetric factor. This behaviour verifies that the Eu3+ ion is in a site of low symmetry. The X-ray absorption near edge structure results reveal that the reduction of Eu3+ to Eu2+ is induced by ionising radiation and the intensity of the X-ray excited optical luminescence emission is inversely proportional to the concentration of lithium.

Efficiency enhancement of silicon solar cells covered by GeO2-PbO glasses doped with Eu3+ and TiO2 nanoparticles

An objective of the solar industry is to improve the efficiency of the light -electricity conversion process of photovoltaic solar cells. An alternative to achieve this purpose is to manage the solar spectrum that is absorbed by the solar cell in order to match it with the solar cell responsivity. It can be done, for example through the downconversion process, covering the solar cell with photonic materials that can convert photons of the UV region to photons with energy close to the band gap energy of the solar cell. This process can be observed, for example, through the UV excitation of transparent glasses with low phonon energy hosting luminescent ions with energy levels in the VIS region. The luminescence from these energetic levels can be improved siting the luminescent ions in places with low symmetry. In the present study the optical response to the solar spectrum of GeO2-PbO glasses containing Eu3+ ions and titanium dioxide nanoparticles was explored to enhance the efficiency of polycrystalline silicon solar cells. Results revealed a maximum efficiency enhancement of 15.92% for the silicon solar cell covered with GeO2-PbO glass doped with 1% of Eu2O3 and 0.5% of TiO2 heat treated for 24 h. This efficiency enhancement was attributed to the location of the Eu3+ ions in sites of low symmetry of TiO2 nanoparticles.

Rearrangement in the local, electronic and crystal structure of europium titanates under reduction and oxidation

We studied powder samples of europium titanates Eu1−x2+Eux3+TiO3+x/2 prepared by sol-gel and coprecipitation methods with subsequent thermal treatment of precursors at different conditions (reducing or oxidizing atmosphere, temperature, exposure time). We have revealed a radical rearrangement in the local, electronic and crystal structure of europium titanates depending on synthesis conditions. The combination of synchrotron X-ray diffraction (s-XRD), X-ray absorption (XANES and EXAFS), infrared and Raman spectroscopies supplemented by photoluminescence and simultaneous thermal analysis was used in our study. It is shown that the combined XANES and thermogravimetric analysis gives clear evidence of a change in the oxidation state of europium cations from Eu2+ to Eu3+. The comparison of s-XRD, XANES, and EXAFS data allowed us to explain the local structure rearrangement during the phase transition from cubic perovskite Eu2+TiO3 (space group Pm3¯m) to pyrochlore phase Eu23+Ti2O7 (space group Fd3¯m) through intermediate layered perovskite Eu23+Ti2O7 with monoclinic structure (space group P21) under annealing in oxidizing atmosphere. The Raman spectroscopy study pointed to significant changes in the local structure of the anionic sublattice upon the observed phase transitions. The analysis of luminescence spectra has shown that Eu3+ cations occupy positions with low local site symmetry in all synthesized compounds regardless of the type of the crystal structure.

Finding the Right Blend: Interplay Between Structure and Sodium Ion Conductivity in the System Na5AlS4-Na4SiS4.

The rational design of high performance sodium solid electrolytes is one of the key challenges in modern battery research. In this work, we identify new sodium ion conductors in the substitution series Na5-xAl1-xSixS4 (0 ≤ x ≤ 1), which are entirely based on earth-abundant elements. These compounds exhibit conductivities ranging from 1.64 · 10−7 for Na4SiS4 to 2.04 · 10−5 for Na8.5(AlS4)0.5(SiS4)1.5 (x = 0.75). We determined the crystal structures of the Na+-ion conductors Na4SiS4 as well as hitherto unknown Na5AlS4 and Na9(AlS4)(SiS4). Na+-ion conduction pathways were calculated by bond valence energy landscape (BVEL) calculations for all new structures highlighting the influence of the local coordination symmetry of sodium ions on the energy landscape within this family. Our findings show that the interplay of charge carrier concentration and low site symmetry of sodium ions can enhance the conductivity by several orders of magnitude.

Photoluminescence properties of a Dy3+, Na+-activated yafsoanite Ca3Zn3Te2O12 phosphor with excellent thermal stability

Novel yafsoanite yellow-emitting phosphors Ca(3−2x)DyxNaxZn3Te2O12 (x = 0.005, 0.01, 0.02, 0.05, 0.08, 0.10, and 0.15) were prepared via the traditional solid-state reaction at 1050 °C for 12 h in the air. The X-ray diffraction (XRD) pattern revealed that all the phosphors adopted garnet-typed yafsoanite structure. The photoluminescence spectra of Ca3Zn3Te2O12:Dy3+,Na+ phosphor exhibited an intense yellow-emitting emission, which indicated Dy3+ ions located at low symmetry sites in the Ca3Zn3Te2O12 host. The optimum concentration of Dy3+ was obtained to be 8%. Thermal quenching experiment showed that the PL intensity of Ca3Zn3Te2O12:0.08Dy3+,0.08Na+ phosphor can maintain 85% as heated up to 423 K compared to the initial one at room temperature. All the results showed that Ca3Zn3Te2O12:Dy3+,Na+ was a new kind of yellow emitting candidate for white LED (light-emitting diodes) applications.