Study on molten salt synthesis, microstructural determination and white light emitting properties of CoNb2O6:Dy3+ phosphor

Ekmekçi, Mete Kaan; İlhan, Mustafa; Güleryüz, Lütfiye Feray; Mergen, A.

doi:10.1016/j.ijleo.2016.10.012

Cited by 17 publications

(8 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rare earth (RE) ions with 4f-4f inner shell transitions have undoubtedly contributed greatly to the development of luminescence applications and the increase in their usage areas. Therefore, the RE ion activated phosphors lead to numerous innovations in the development of new generation devices in various fields such as screen-display technology, lighting technology, and optical data communication due to some positive features such as long life, energy saving, improved physical durability, small size, fast switching, high efficiency, and environmental friendliness (1- 19). The trivalent neodymium ion (Nd 3+ ), one of the oldest trivalent lanthanide ions used in solid-state laser, is well known for its useful laser transitions such as F3/2→ 4 I9/2, 4 F3/2→ 4 I11/2, and 4 F3/2→ 4 I13/2 (20)(21)(22)(23)(24)(25)(26)(27)(28)(29).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Structural, Near-Infrared Luminescence, and Radioluminescence Properties of Nd3+ Activated TTB-Lead Metatantalate Phosphors

İlhan

Keski̇n

2023

Journal of the Turkish Chemical Society Section A: Chemistry

Self Cite

View full text Add to dashboard Cite

The study reports the structural and spectroscopic properties of Nd3+ doped lead metatantalate phosphor series fabricated by conventional solid state method. XRD results of the PbTa2O6 phase confirm the tungsten bronze symmetry and single-phase structure between 0.5 and 10 mol% Nd3+ concentrations. The lead decrease in the structure can be associated with maintaining the charge balance and single phase due to evaporation during sintering. In SEM micrographs, the grains exhibited shapeless morphology, and the grain sizes varied from 0.5 to 7 m. In EDS results, the increase of Ta/Pb ratio in grain surfaces indicated some lead evaporation, as reported in previous studies. The absorption spectrum of PbTa2O6 host peaked around 275-280 nm, and the band gap was found to be 3.7±0.2 eV. The absorptions of Nd3+ doped phophors shifted the high wavelenght or the low band gap, where the band gaps were found between 3.1±0.2 and 3.3±0.2 eV. The PL emissions of the phosphors in near-inrared region were observed with the transitions of 4F3/2→4I9/2 (at 875 nm) and 4F3/2→4I11/2 (at 1060 nm) of Nd3+. The RL emissions or X-ray excited luminescence were monitored with the transitions of 4F3/2→4I9/2 (at 875 nm), 4F3/2→4I11/2 (at 1065 nm) in the infrared region, and the transitions of 2F(2)5/2→4F9/2, 2F(2)5/2→2H(2)11/2, 2F(2)5/2→4G5/2, 2F(2)5/2→4G7/2, 2F(2)5/2→4G9/2 in the visible region corresponding to at around 430, 455, 490, 525, and 570 nm, respectively. PL and RL emissions of the phosphors exhibited the decreasing emission intensity over 5 mol% due to the concentration quenching which may be associated with cross-relaxing mechanism. In the PL and RL spectral profiles, the similarity of splitting levels was attributed to the similarity of the local symmetry of the ligand ions surrounding the Nd3+ ion. The CIE coordinates obtained using RL emissions were found close to the blue region due to visible region transitions.

show abstract

Section: Introductionmentioning

confidence: 99%

Evaluation of the Structural, Near-Infrared Luminescence, and Radioluminescence Properties of Nd3+ Activated TTB-Lead Metatantalate Phosphors

İlhan

Keski̇n

2023

Journal of the Turkish Chemical Society Section A: Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…The MNb2O6 structure has a significant benefit in that it can host guest ions that have ionic sizes comparable to those of the Nb and divalent M 2+ ions present in the structure. As MNb2O6 structure, cobalt niobate (CoNb2O6) compound consisting of the CoO6-NbO6 octahedral (15)(16)(17)(18) has been studied due to its magnetic (19)(20)(21)(22), neutron scattering (23), dielectric (24), optical (25)(26)(27), gas sensing (28,29) magneticthermodynamic (29,30) properties. MNb2O6 (M= Ni, Zn, Co) sensing electrodes (SEs) were produced and studied for NO2 detection at high temperature where CoNb2O6 electrode has the highest sensibility at 750 o C among the oxide SEs (29).…”

Section: Introductionmentioning

confidence: 99%

“…The low-temperature heat capacity and spin entropy properties of CoNb2O6 have been investigated (31). The molten salt method is one of the favorite synthetic methods used in the synthesis of niobates due to its advantageous properties such as short reaction time, low sintering temperature, improved homogeneity, and crystallinity (15,18,(25)(26)(27). The superiority of the molten salt method may be assessed by comparison of the conventional solid-state method.…”

Section: Introductionmentioning

confidence: 99%

Structural Properties, Photoluminescence, and Judd-Ofelt Parameters of Eu3+- Doped CoNb2O6 Phosphor

İlhan

Güleryüz

Ekmekçi

2023

Journal of the Turkish Chemical Society Section A: Chemistry

Self Cite

View full text Add to dashboard Cite

Trivalent Eu-activated CoNb2O6 phosphors were fabricated using the molten salt method, which provides enhanced homogeneity and low sintering temperature. The ceramic samples were examined by spectral and structural analyses. In X-ray diffractions, the single phase of orthorhombic columbite type CoNb2O6 structure was obtained for 0.5-10 mol% Eu3+ doping concentrations, while a two theta peak shift towards the smaller angles occurred. SEM examinations show an irregular morphology and sub-micron grain sizes. In photoluminescence (PL) spectra, the phosphors showed typical Eu3+ emissions with the 5F0 → 7FJ (J=0, 1, 2, 3, 4) transitions, and high emission peaks were observed at the 5D0 → 7F2 transition. The photoluminescence of CoNb2O6:Eu3+ decreased over 5 mol% because of the concentration quenching. The energy transfer mechanism and critical distance of the phosphor are the dipole-dipole (d–d) interaction, and 15.70 Å, respectively. The spectral features of the phosphors were assessed by calculating the Judd-Ofelt intensity parameters (Ω2, Ω4) from the PL emission spectrum. The low Ω2 parameter values or/and the Ω4>Ω2 trend for CoNb2O6:Eu3+ phosphors were related to the less covalent or more ionic character of the Eu3+–O2˗ bond and the high local symmetry of the Eu3+ sites, while the high Ω4 parameter values may be ascribed to the decrease in the electron density in the ligands.

show abstract

“…Trivalent lanthanide (Ln 3+ ) ions exhibiting 4f-4f inner-shell transitions have certain properties such as high luminescence efficiency, narrow emission line, and long decay time constant. Due to their advantages, such as reliability and environmental friendliness, they have attracted great attention as new generation solid-state lighting sources in recent years (1)(2)(3)(4)(5)(6)(7)(8)(9). Among these materials, trivalent europium, which is used as a dopant in the production of inorganicbased red light emitting phosphors (LEDs), is known as an effective activator due to its characteristic 5 F0 → 7 FJ (J = 0, 1, 2, 3, 4, 5) band transitions.…”

Section: Introductionmentioning

confidence: 99%

Influence of europium doping on the crystallization, morphology, and the cathodoluminescent properties of PbNb2O6:Eu3+ phosphors

Ekmekçi

2022

Journal of the Turkish Chemical Society Section A: Chemistry

View full text Add to dashboard Cite

Undoped PbNb2O6 and Eu3+ ion doped PbNb2O6 samples were synthesized by high temperature mixed oxide method, applying a heat treatment temperature of 1250°C and an annealing time of 6 hours. In order to elucidate the structural and optical behavior of PbNb2O6:Eu3+ phosphors, XRD (X-ray diffraction), SEM (scanning electron microscopy), EDS (energy dispersive spectroscopy), CL (cathodoluminescence) and absoption analyses were performed. The X-ray diffraction results showed that the undoped PbNb2O6 sample crystallized in a rhombohedral symmetry while Eu3+ doped samples formed in orthorhombic symmetry. The morphologies of the rhombohedral and orthorhombic grains were examined by SEM-EDS. The CL spectra showed spectral profiles between 580 and 780 nm in relation to the 4f–4f transitions of Eu3+. A strong emission was observed at about 620 nm, corresponding to the red color and associated with the 5D0 → 7F2 transition of Eu3+, while the undoped sample did not exhibit CL emission of the host which is probably due to the presence of lead in the host structure. In addition, the CL analysis results showed that the emission intensity increased with the increase of Eu3+ ion concentration. The increase in magnetic dipole transition caused by the electron beam radiation effect of the CL with increasing doping concentration is associated with the change of dipole moments of the Eu3+ doped tungsten bronze host and thus differentiating the emission spectrum. UV lamp excited photograph of undoped sample showed blue-violet color while Eu3+ doped phosphors with red color became more significant with increasing Eu3+ concentration.

show abstract

Study on molten salt synthesis, microstructural determination and white light emitting properties of CoNb2O6:Dy3+ phosphor

Cited by 17 publications

References 24 publications

Evaluation of the Structural, Near-Infrared Luminescence, and Radioluminescence Properties of Nd3+ Activated TTB-Lead Metatantalate Phosphors

Evaluation of the Structural, Near-Infrared Luminescence, and Radioluminescence Properties of Nd3+ Activated TTB-Lead Metatantalate Phosphors

Structural Properties, Photoluminescence, and Judd-Ofelt Parameters of Eu3+- Doped CoNb2O6 Phosphor

Influence of europium doping on the crystallization, morphology, and the cathodoluminescent properties of PbNb2O6:Eu3+ phosphors

Contact Info

Product

Resources

About