Enhancing the blue luminescence behaviour of the Li co -doped novel phosphor ZnB 2 O 4: Tm 3+

[No Abstract Available]Scientific Research Projects of Cukurova University-Turkey [FDK-2017-7905]The authors are grateful for the financial support from the Scientific Research Projects of Cukurova University-Turkey, FDK-2017-7905 project

Eu3+ and Dy3+ doped La2MoO6 and La2Mo2O9 phosphors: Synthesis and luminescence properties

We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. The formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (4F9/2 ›6H15/2) and 572 nm (4F9/2 › 6H13/2), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (5D0 ›7F2) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. The present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting. © 2019 Elsevier Lt

Eu3+ and Dy3+ doped La2MoO6 and La2Mo2O9 phosphors: Synthesis and luminescence properties

We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. The formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (F-4(9/2) -> H-6(15/2)) and 572 nm (F-4(9/2) -> H-6(13/2)), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (D-5(0) -> F-7(2)) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. The present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting

Novel Dy incorporated Ca3Y2B4O12 phosphor: Insights into the structure, broadband emission, photoluminescence and cathodoluminescence characteristics

This study reports cathodoluminescence (CL) and photoluminescence (PL) properties of undoped borate Ca3Y2B4O12 and Ca3Y2B4O12:x Dy3+ (x = 0.5, 1, 2, 3, 5, and 7) synthesized by gel combustion method. Micro-X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), CL and PL under electron beam and 359 nm pulse laser excitation, respectively were used to investigate characterization and luminescence studies of synthesized samples in the visible wavelength. As-prepared samples match the standard Ca3Y2BO4 phase that belongs to the orthorhombic system with space group Pnma (62) based on XRD results. Under electron beam excitation, this borate host shows a broad band emission from about 250 to 450 nm, peaked at 370 nm which is attributed to NBHOC. All as-prepared phosphors exhibited the characteristic PL and CL emissions of Dy3+ ions corresponding to 4F9/2→6HJ transitions when excited with laser at 359 nm. The CL emission spectra of phosphors were identical to those of the PL spectra. Concentration quenching occurred when the doping concentration was 1 mol% in both the CL and PL spectra. The underlying reason for the concentration quenching phenomena observed in the discrete orange-yellow emission peaked at 574 nm of Dy3+ ion-doped Ca3Y2B4O12 phosphor is also discussed. According to these data, we can infer that this new borate can be used as a yellow emitting phosphor in solid-state illumination.This work was supported by İzmir Bakırçay University Scientific Research Projects Coordination Unit, under grant number GDM.2021.003 and the Spanish Project entitled Rock-Eaters, PID-2019-105469RB-C22.Peer reviewe

Structural and temperature dependence luminescence characteristics of RE (RE=Eu3+, Dy3+, Sm3+ and Tb3+) in the new gadolinium aluminate borate phosphor

GdAl3(BO3)4:Dy3+, Sm3+, Eu3+, and Tb3+ samples were successfully achieved via a sol-gel combustion method. The observed XRD analysis confirms the formation of the desired GAB host, indicating rhombohedral structures that agree well with JPCD card number 72–1985. The FTIR analyses show the detection of B O stretching and B O B bending modes as well as Al O and Gd O bonds in the phosphor samples. Energy dispersive spectroscopy (EDS) analysis reveals that Sm, Eu, Dy, and Tb have been successfully doped into GdAl3(BO3)4. The observed broad intrinsic luminescence band can be caused by oxygen-induced luminescence defects in the GAB host with hydrous precursors. The luminescence properties of rare earth ion-doped GdAl3(BO3)4 samples are analysed by photoluminescence spectra, showing their optimal doping concentrations and critical distances of Dy3+, Eu3+, Sm3+ and Tb3+ are 2 wt% 25.8 Å, 7 wt% 17 Å, 1 wt% 32.59 Å, and 7 wt% 17.03 Å. Additionally, the energy transfer mechanism for luminescence quenching was determined as dipole-dipole (for Dy3+, Eu3+, and Tb3+) or dipole-quadrupole (for Sm3+) and the cross-relaxation process. GdAl3(BO3)4 samples obtained by doping with different RE3+ ions exhibit intense light emissions with different colors originating from different RE3+ ions under 349 nm excitation. When doped with different concentrations of RE3+ ions, the luminescence properties of the samples changed. The synthesized luminescence materials have potential applications in lighting and display technologies.Peer reviewe

Thermoluminescence study and evaluation of trapping parameters of samarium doped barium silicate phosphor

We report the detailed analysis of thermoluminescence (TL) glow curves and the evaluation of kinetic parameters of Sm3+-incorporated BaSi(2)O(5.)The effect of various heating rates on TL kinetics and glow peak temperatures of Sm3+-doped BaSi2O5 phosphors exposed to beta particle irradiation at room temperature are investigated. The glow curve of the phosphor exposed to beta-irradiation consists of two main peaks with maxima at about 91 degrees C and 193 degrees C and exhibits good linearity between 1 and 10 Gy. The activation energies and frequency factors of trap centers involved in the TL emission were calculated from the TL glow curve of the sample by means of variable heating rate (VHR), repeated initial rise (RIR), and computerized glow-curve deconvolution (CGCD). Analysis of the main dosimetric peak techniques indicate that activation energies (E) and pre-exponential factor (s) vary between 0.93 and 1.72 eV, 10(10) and 10(13) s(-1). It is found that the temperature of the glow peaks shifts toward the higher temperatures and the TL intensity smoothly decreases as the heating rate increases. The behavior of the TL intensities and glow peak temperatures as a function of the heating rate are discussed with regards to thermal quenching.Jazan University [W41-032]This work was supported by the Jazan University [W41-032]

Eu3+ and Dy3+ doped La2MoO6 and La2Mo2O9 phosphors: Synthesis and luminescence properties

We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. The formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (4F9/2 →6H15/2) and 572 nm (4F9/2 → 6H13/2), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (5D0 →7F2) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. The present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting. © 2019 Elsevier Lt

Enhancing the blue luminescence behaviour of the Li co-doped novel phosphor ZnB2O4: Tm3+

Here we report a detailed structural analysis, and properties of the cathodoluminescence (CL), photo-luminescence (PL) and 3D thermoluminescence spectra of the Tm3þincorporated ZnB2O4phosphorsuccessfully synthesized through wet-chemical synthesis. The formation of a single-phase compound isverified through X-ray diffraction (XRD) studies. The phosphor shows an efficient blue emission locatedat 458 nm corresponding to1D2/3F4under both a low voltage electron beam and UV excitation. Theoptimal concentration of the doped Tm3þis 0.5 mol% in CL and PL measurements. The correspondingconcentration quenching mechanism is confirmed to be a multipole-multipole interaction, and thecritical distance between Tm3þions is estimated to be 34 Å. Incorporating Liþremarkably enhances theluminescence intensity probably because of the charge compensation effect. Li ions are speculated tofillthe defects in the ZnB2O4host and then the excitation energy transfers from the host to Tm3þ. Sur-prisingly, the thermoluminescence spectra of ZnB2O4:Tm3þand Liþco-doped ZnB2O4:Tm3þrecorded inthe temperature range 30e400 C follow a different pattern compared with PL and CL data. The domi-nant signals come from Tm3þsites. Above room temperature, the Tm3þions do not show the peaktemperature movement, but do exhibit a different pattern with the addition of co-doped Liþions. Theseresults indicate that these phosphors are promising candidates for luminescence-based optoelectronicdevices.The authors are grateful for thefinancial support from the Scientific Research Projects of Cukurova University Turkey, FDK-2017-7905 project