Cathodoluminescence properties of La2MoO6:Ln3+ (Ln: Eu, Dy, and Sm) phosphors

La2MoO6 orange-red phosphors with high efficiency incorporated with Eu, Dy and Sm have been synthesized through a gel combustion method. The influences of rare earth doping in synthesized samples were analysed by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and cathodoluminescence. Rare earth doped La2MoO6 samples show strong emission bands in the range of 400–750 nm and optimal doping concentration for all samples was 2 mol%. La2MoO6 host doped Eu ion showed intense and predominant emission peaks in 450–750 nm range. The electrical multipolar interaction contributed to the non-radiative energy transfer between Eu3+ ions in La2MoO6 host matrix. Sm doped La2MoO6 host exhibited orange-red CL emission peaks at 564, 608, 652 and 708 nm La2MoO6:Dy3+ phosphor displayed emissions at 484, 574 and 670 nm, respectively. The observed intense and sharp emission peaks indicate that La2MoO6 is promising host for lanthanides doped phosphor materials in the applications of optoelectronic. © 2020 Elsevier Lt

Microstructural and Radioluminescence Characteristics of Nd3+ Doped Columbite-Type SrNb2O6 Phosphor

Undoped and different concentration Nd3+ doped SrNb2O6 powders with columbite structure were synthesized by molten salt process using a mixture of strontium nitrate and niobium (V) oxide and NaCl-KCl salt mixture as a flux under relatively low calcining temperature. X-ray diffraction analysis results indicated that SrNb2O6 phases found to be orthorhombic columbite single phase for undoped, 0.5 and 3 mol% Nd3+ doping concentrations. Phase composition of the powders was examined by SEM-EDS analyses. Radioluminescence properties of Nd3+ doped samples from UV to near-IR spectral region were studied. The emissions increased with the doping concentration of up to 3 mol%, and then decreased due to concentration quenching effect. There is a sharp emission peak around 880 nm associated with 4F5/2 → 4I9/2 transition in the Nd3+ ion between 300 and 1100 nm. The broad emission band intensity was observed from 400 to 650 nm where the peak intensities increased by increasing Nd3+ doping concentration. All the measurements were taken under the room temperature. © 2017, Springer Science+Business Media New York

Synthesis and competitive luminescence quenching mechanism of Ca(3)Al(2)O(6)Ln(3+)(Ln: Dy and Sm) phosphors

Sm3+ and Dy3+ activated Ca3Al2O6 phosphors were produced through a gel combustion method using Urea + beta-Alanine, Urea, and Urea + Glycine as fuels. The crystal structure and the phase purity of the obtained materials were characterized by X-ray powder diffraction (XRD). Ca3Al2O6 :Sm3+ phosphor shows characteristic emission lines (565 nm, 602 nm, 649 nm, and 714 nm) in the orange red region assigned to (4)G(5/2) -> H- 6(J) (J = 5/2, 7/2, 9/2, 11/2) transitions of Sm3+. The strongest peak is located at 602 nm. Emission spectra of Ca3Al2O6 :Dy3+ show that there are two dominant peaks centered at 480 nm and 573 nm emitting blue and yellow light. Optimum doping concentrations of Sm(NO3)(3) and Dy(NO3)(3) are 0.01 % and 0.03 %, respectively. The concentration quenching mechanism is verified to be a dipole-dipole interaction as the type of energy transfer among Sm3+-Sm3+ and Dy3+-Dy3+ ions. The critical distance is also calculated to be 24.19 angstrom and 16.77 angstrom, respectively

Synthesis and enhanced photoluminescence of the BaSiF6:Dy3+ phosphors by Li+ doping via combustion method

Undoped BaSiF6, Dy3+ doped BaSiF6, and Dy3+, Li+ co-doped BaSiF6 phosphors were synthesized through a gelcombustion method. The prepared samples were characterized by powder x-ray diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive x-ray spectroscopy (EDS), and photoluminescence (PL) techniques. The XRD data revealed that both the Dy3+ doped and Li+ co-doped BaSiF6 phosphors exhibited a single-phase structure belonging to the space group R (3m) over bar which matched well with the standard JCPDS files (No. 002-6613). FTIR spectra showed absorption bands at 3417 cm -1 , 1640 cm(-1), and 1620 cm(-1) corresponding to water molecules. EDS analysis confirmed the chemical composition of the prepared samples. The PL emission spectra of BaSiF6:Dy3+ by different co-doping concentrations of Li+ exhibited prominent emission peaks at 490 nm, 572 nm, 672 nm and 758 nm. The incorporation of Li+ is beneficial for enhancing the photoluminescence intensity. The optimum Li+ amount was 8% for BaSiF6:Dy3+ and then started to decrease. The enhancement could be due to the occurrence of oxygen vacancies due to the incorporation of Li+ ions. The x = 0.301 and y = 0.361 coordinates of this phosphor with varying Li+ dopant concentration determined by the Commission Internationale de l'Eclairage (CIE - 1931) were in the white range. The present work demonstrates how a simple and effective method can be used to prepare novel nanophosphors for applications in the field of visible light emitting devices with enhanced white emission