Photoluminescence emissions of Ca_(1-x)WO_(4):xEu^(3+):Bridging between experiment and DFT calculations

In this work,the impact of the doping process on the photoluminescence emission of CaWO_(4) as a function of the concentration of Eu^(3+) cation(0.01 mol%,0.02 mol%,0.04 mol%,0.06 mol%,0.08 mol%,and 0.10 mol%) is discussed in detail.Ca_(1-x)WO~4:xEu^(3+) samples were successfully synthesized by a simple coprecipitation method followed by microwave irradiation.The blue shift in the absorption edge confirms the quantum confinement effect and the band gap energy covers the range from 3.91 to 4.18 eV,as the amount of Eu^(3+) cations increases.The experimental results are sustained by first-principles calculations,at the density functional theory level,to decipher the geometry and electronic properties,thereby enabling a more accurate and direct comparison between theory and experiment for the Ca_(1-x)WO_(4):xEu^(3+) structure.

The Site Symmetry of Eu^(3+) in ZnS:Eu Nanoparticle

Nanosized ZnS doped with different concentrations of Eu3+ were prepared andanalyzed by x-ray diffraction technique. The experimental results show that ZnS belongs to thecubic structure. From the photoluminescence (PL) emission spectra, it can be seen that the ratioof the emission intensity of Eu3+ at 616 nm to that at 590 nm increases as the increasing of Eu3+.This phenomenon reveals that the site symmetry of Eu3+ reduces as the increasing of Eu3+.

Effects of annealing temperature and neodymium concentration on structural and photoluminescence properties of Nd^(3+)-doped Y_(2)O_(3)-SiO_(2) powders

We report the structural and photoluminescence(PL) properties of Nd^(3+)-doped Y_(2)O_(3)-SiO_(2) powders(Y_(2)O_(3)-SiO_(2):Nd^(3+)) as functions of annealing temperature and Nd^(3+) ion doping concentration.Y_(2)O_(3)-SiO_(2):Nd^(3+)powders were prepared using the high-energy ball-milling(HEBM) method,and their structural and PL properties were investigated using X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy,and PL spectroscopy.The XRD results reveal a cubic phase without impurities,and the peak broadening decreases with an increase in annealing temperature due to the increase in the crystallite size.The PL emission intensity increases with an increase in annealing temperature.The highest PL emission intensity is observed for the 300-min milled mixture annealed at 1000℃ for 1 h with a Nd^(3+) concentration of 1 mol%.The PL peaks excited by 800 nm radiation were detected,centered at 1080 nm(^(4)F_(3/2)→^(4)I_(11/2)) and 1350 nm(^(4)F_(3/2)→^(4)I_(13/2)).

Photoluminescence properties and effect of Bi^(3+) dopant of Eu^(3+) and Dy^(3+) co-doped Sr_3V_2O_8

Photoluminescence properties of Sr 2.5 Dy 1/3-x Eu x V 2 O 8（x=0,0.06,0.12,0.18,0.24,0.33） were investigated.The excitation spectra included a broad band in the short wavelength region and several sharp lines in the longer wavelength region,and the spectral origin were discussed.The emission spectra were measured in two different exciting ways,i.e.,exciting the VO 4 group at 270 nm and the Eu 3＋ ion at 398 nm,respectively,and the energy transferring process was reasonably suggested.Furthermore,multi-color emission could be achieved in Sr 2.5 Dy 1/3-x Eu x V 2 O 8,indicating that the studied samples had potential applications in the white light emitting diodes.Further investigation showed that reducing the concentration of Eu 3＋ and Dy 3＋ and introducing Bi 3＋ as a sensitizer ion greatly enhanced the emission intensity.

The sprayed ZnO films: nanostructures and physical parameters

We synthesized the pure and indium-doped （IZO） ZnO films with a facile composition control spray pyrolysis route. The substrate temperature （Ts） and In-doping effects on the properties of as-grown films are inves- tigated. The X-ray pattern confirms that the as-synthesized ZnO phase is grown along a （002） preferential plane. It is revealed that the crystalline structure is improved with a substrate temperature of 350 ℃ Moreover, the morphol- ogy of as-grown films, analyzed by AFM, shows nanostructures that have grown along the c-axis. The （3 ×3 μm2） area scanned AFM surface studies give the smooth film surface RMS 〈 40 nm. The UV-VIS-IR measurements reveal that the sprayed films are highly transparent in the visible and IR bands. The photoluminescence analysis shows that the strong blue and yellow luminescences of 2.11 and 2.81 eV are emitted from ZnO and IZO films with a slight shift in photon energy caused by In-doping. The band gap is a bit widened by In-doping, 3.21 eV （ZnO） and 3.31 eV （IZO） and the resistivity is reduced from 385 to 8Ω·m. An interesting result is the resistivity linear dependence on the substrate temperature of pure ZnO films.