•Dy3+-activated new BaYAlZn3O7 nanopowders have been fabricated via an energy and time saving solution combustion route.•Rietveld refinement technique disclosed their phase-purity and intrinsic ...crystal framework.•In-depth down-conversion photoluminescence and the effectual energy-relocation has been thoroughly scrutinized.•Potential candidate for cool-WLEDs, digital-signs, horticulture, bio-imaging, solar-cells and lasers.
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Ongoing progress of solid-state illumination technology necessitates the compelling need for energy-efficient nanophosphors with superfine luminance. The present paper reports the synthesis and characterization of nano-crystalline phosphors by incursion of Dy3+ ions into BaYAlZn3O7 matrix. Rietveld-refinement of XRPD profiles revealed the hexagonal structure of as synthesized nano-crystalline phosphors. Non-uniform agglomerated particles with size ranging between 44 and 65 nm have been observed from morphological investigation. The observed white light in the studied nanophosphors is due to emissions lying in blue and yellow domains radiated from 4F9/2 to 6H15/2, 13/2 states of Dy3+ respectively. Inokuti-Hirayama (I-H) and Dexter’s models have been employed to understand the phenomenon of Photoluminescence. It has been observed that d-d (dipole-dipole) inter-linkages chiefly command the luminance-quenching for nanophosphor with Dy3+ content (x) equal to 0.05. Various radiative-possessions reflecting better luminance-potentiality of presently studied nanophosphor like decay-time, intrinsic life-time, quantum-efficiency and relaxation-rate have also been evaluated. White light parameters viz. CP and CCT values of BaY0.95Dy0.05AlZn3O7phosphors are 19.84 × 10−2 and 8088.31 K, respectively along with CIE-1931 coordinates (x = 0.2588, y = 0.3306), imply the studied nanophosphor to be a new superfine cool-white-emanating material for nUV-activated WLEDs (white-light-emanating diodes), portable-electronics, signage, aircraft-cabins, digital communication, sensors, horticulture, solar-cells and advanced lasers. The reported outcomes will certainly open an avenue for researchers to design more BaYAlZn3O7-like materials.
This study features structural and photometric aspects of a down-converted green emanating erbium (Er3+) activated nanophosphor synthesized via a versatile and environmentally benign urea aided ...solution combustion procedure. The powder X-ray diffraction pattern (PXRD) of optimal sample SrGd1.96Er0.04Al2O7 studied qualitatively by employing the Rietveld refinement practice, disclosed the tetragonal crystal phase with space group 14/mmm (139), consisting grains of size 50.03 nm. Surface morphology and grain size of nanopowders were well investigated by electron microscopy practices like scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). SEM micrograph gave clear insight that Er3+ doped nanophosphors possess slightly agglomerated particles with pores, voids and cracks due to high pressure breakout of gases while combustion synthesis. TEM and SEM images revealed the size of nanoparticles in the ambit of 40–60 nm which was in coherence with that obtained from the scherrer's equation, while the inter-fringes distance corresponding to diffraction plane (116) was calculated to be 0.27 nm from the HRTEM image. The desired nanophosphor showed brilliant green emission with an intense peak at 551 nm attributed to 4S3/2 → 4I15/2 transition of Er3+ ions, as analyzed through photoluminescent (PL) emission spectra monitored via near ultraviolet excitation wavelength (381 nm) with an optimal doping concentration of 2.0 mol%. Advanced photometric features like CIE color coordinates (0.3017, 0.6043), CCT (6032K), and color purity (76.52%) confirmed their green glow and are found to be in harmony with standard green emission. The study offers a luminous cool green emanating component for the fabrication of WLEDs and advanced optoelectronic appliances.
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•SrGd2Al2O7:Er3+ nanophosphors were prepared via combustion procedure.•Absolute crystal phase was analyzed using XRD assisted Rietveld Refinement technique.•The new down-converted nanophosphors exhibit excellent green luminescence.•CIE chromaticity co-ordinates, CCT and color purity were inspected thoroughly.•Potential candidate for cool WLEDs, lasers and optical sensors.
A series of five virescent color emitting terbium(III) complexes is fabricated by a cost-effective and eco-friendly solution precipitation technique with the utilization of ...1-(4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid (L) as a primary ligand and highly conjugated nitrogen donor secondary ligands such as bathophenanthroline (batho), 5,6-dimethyl-1,10-phenanthroline (dmph), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy). The elemental compositions of complexes are examined through energy dispersive x-ray and elemental analyses, whilst the binding nature of ligand with terbium(III) ion is confirmed using proton nuclear magnetic resonance and infrared spectroscopy. The band gap energy (
E
g
) of complexes is found in the range of 3.85–3.34 eV as evaluated from diffuse reflectance spectral data. The significant thermal stability of these luminescent materials (157°C) demonstrates their key role as virescent component in white organic light emitting diodes. The intense emission and decay time of complexes are explored through photoluminescent study. The good color purity and Commission International De I’Eclairage color coordinates promise the enhanced performance of these materials in lighting appliances. The sensitization phenomenon highlights the role of ligands in increasing the luminescence intensity of complexes. The biological assessment indicates that the complexes are potent antimicrobial and antioxidant agents. The aforementioned features extend the field of applications of complexes in laser technology and optoelectronic devices.
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•Five new europium(III) complexes have been synthesized via solution precipitation method.•CHN, EDAX, IR, NMR, TG-DTG, SEM, DR and PL analysis of complexes have been ...done.•Photoluminescence, color purity confirm the bright red emission of complexes in visible region.•Potential candidate for potent antimicrobial and antioxidant agents.
Europium based five luminescent europium(III) complexes with 2-hydroxy-4-ethoxyacetophenone (main ligand) and second chromophores, bathophenanthroline, 5,6-dimethyl-1,10-phenanthroline, 1,10-phenanthroline and 2,2-bipyridyl have been prepared by employing cost-effective solution precipitation method. The various advanced techniques are employed to investigate the structural information. Thermal study proclaims the thermal stability of complexes up to 155 °C. The analyzed band-gap for complexes opens the application of these complexes in laser system. The photoluminescent properties of complexes under ultraviolet light clearly reveal the presence of prominent emission peak (5D0→7F2 transition) centered at 611 nm responsible for intense red emission of complexes, which highlights the applicability of these complexes in advanced optoelectronic devices. Judd-Ofelt intensity parameters, internal quantum efficiency and sensitization mechanism confirm the luminescence efficiency of complexes. The complexes display the excellent antimicrobial and antioxidant features.
A white light emitting Barium gadolinium vanadate, Ba2GdV3O11:Eu3+, is developed using time-saving combustion synthesis technique. The Rietveld analysis of the optimum luminescent composition ...(Ba2Gd0.97V3O11:0.03Eu3+) confirmed that it crystallizes into the monoclinic system with P21/a space group. The calculation of lattice parameters unveiled the unit cell expansion which in turn governed the asymmetry around activator. The photoluminescent analysis showed an efficient energy transfer from vanadate absorption of Ba2GdV3O11 host to Eu3+, resulting in a very intense characteristic emission of the Eu3+. The PL decay investigations of Ba2GdV3O11:0.03Eu3+ nanophosphor gave the radiative lifetime and total spontaneous emission probabilities. Judd-Ofelt parameterization provided the refractive index of the host and stimulated emission cross section for 5D0?7F4 (8.03) transition in Ba2GdV3O11:0.03Eu3+ phosphor. The quantum efficiency of 5D0 state in Ba2Gd0.97Eu0.03V3O11 phosphor was calculated to be 79%, resulting in a pure white emission. All results demonstrate that Ba2Gd0.97V3O11:0.03Eu3+ is a potential candidate for single-phased WLEDs.
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•Ba2GdV3O11:Eu3+ nanocrystals were synthesized via combustion method.•Lattice parameters of optimum fluorescent composition were calculated.•Band-gap was calculated for both the host and doped sample.•Quantum efficiency and peak stimulated emission cross-sections have been determined.•Potential candidate for solid state lighting, and display devices.
A systematic computational analysis is integrated with the experimental records like Rietveld and Judd-Ofelt studies to have a deeper insight into the structural and optoelectronic characteristics of ...Eu3+-doped Ba2LaV3O11 system. The vanadates used were developed via solution combustion-synthesis (SCS) route, with all ab-initio calculations performed in the density functional framework. The Rietveld refinement over Ba2La0.65Eu0.35V3O11 lattice confirmed the phase purity and crystal structure prototype (monoclinic with P21/a space group). The first-principal routed structure-optimization of the pure host unveiled not only the total energy but also the atomic positions which were unknown till date. The experimental band-gap (3.724 eV) was found to be pretty much comparable to the value obtained computationally (3.482 eV). The partial density of states (PDOS) were analyzed orbital-as well as element-wise to understand the electronic structure in a more comprehensive manner. The calculation of dielectric function yielded the value of many important optical properties like refractive index, extinction-coefficient, optical-conductivity, and loss-function. The photoluminescent (PL) excitation-emission and decay analysis revealed a very efficient energy transfer from vanadate absorption of Ba2LaV3O11 to Eu3+; resulting in a significantly intense emission with blue-white-red color tunability. Furthermore, the density-functional assisted PL analysis also provided the Judd-Ofelt parameters (Ω2 = 3.3175 × 10−20 cm2 and Ω4 = 0.1197 × 10−20 cm2), radiative-lifetime (2.03 ms), emission cross-sections (10.80 × 10−22 cm2), quantum efficiencies and radiative rates for 5D0 term. All optoelectronic results of Ba2La0.65Eu0.35V3O11 phosphor suggest that it can be used in the nanocrystalline form for white light emitting diodes (WLEDs) while potentially the bulk crystal in laser devices. Moreover, the results of this report may find applications in designing novel material based upon Ba2LaV3O11 lattice.
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•Judd-Ofelt parameters for Ba2La0.65Eu0.35V3O11 nanocrystals have been determined.•Atomic positions and optical properties for Ba2LaV3O11 are calculated from DFT.•Lattice parameters for Ba2La0.65Eu0.35V3O11 have been found from Rietveld method.•Optical band-gap for Ba2LaV3O11 host is obtained theoretically and experimentally.•Quantum-efficiency and emission cross-sections are obtained for 5D0 state.
A ultraviolet-triggered white light-emitting Ba
2
Gd
1−
x
V
3
O
11
:
x
Dy
3+
nanophosphor series has been developed with the aid of urea-fueled solution combustion route, for the first time. Powder ...x-ray diffraction and Rietveld refinement have been utilized to study the structural features of the synthesized series. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and energy-dispersive spectroscopy (EDS) analysis have been employed for morphological and elemental analysis. When triggered by ultraviolet radiation at 324 nm, the Dy
3+
-doped nanophosphor exhibited characteristic peaks attributed to emissions due to
4
F
9/2
→
6
H
13/2, 15/2
transitions. The concentration quenching phenomenon was witnessed for the 3 mol% fluorescent composition in Dy
3+
-doped Ba
2
GdV
3
O
11
nanophosphor. The Auzel’s model has been of great usage in determining the values for intrinsic lifetime (1.112 ms) and non-radiative rates (421.178 s
−1
). The efficient and cool conduct of the white light-emitting nanophosphor series has been endorsed by the CIE color coordinates (
x
= 0.256,
y
= 0.341), correlated color temperature (CCT = 9751 K), and quantum efficiency value (67%). The structural and photoluminescence behavior featured by the trivalent dysprosium-doped Ba
2
GdV
3
O
11
nanophosphor support its usage in ultraviolet-stimulated lighting devices.
Graphical Abstract
A facile and less time-consuming technique, namely, solution combustion synthesis (SCS) was employed for generating a series of novel BaY1-xZn3AlO7: xEu3+ (x = 0.05–0.30) nanophosphor. Powder X-ray ...diffraction (PXRD) patterns supported with Rietveld refinement technique validated the subsistence of a pure hexagonal BaYZn3AlO7 phase belonging to P63mc (186) space group. Both Scherrer’s equation as well as transmission electron microscope (TEM) study, were in strong agreement in terms of nano-size of the synthesized phosphor. The obtained nanostructures display a most prominent peak in their emission spectra at 611 nm owing to 5D0→7F2 transition resulting in red-emission upon excitation by a source of near-ultraviolet (NUV) light (λex = 393 nm). The observed CIE coordinates for this strong emission in an optimized nanophosphor (BaY0.80Eu0.20Zn3AlO7) were 0.592, 0.407. Judd-Ofelt parameter (Ω2) is evaluated for all compositions of combustion derived nanosamples utilizing their recorded emission spectra by applying Judd-Ofelt theory. The standard host and synthesized nanophosphor containing optimum concentration of Eu3+ i.e. BaY0.80Eu0.20Zn3AlO7 were examined via diffuse reflectance spectroscopy (DRS) and the evaluated energy band gap were established to be 4.67 eV and 4.61 eV respectively. In addition, dipole-quadrupole interactions were apt to cause the observed concentration quenching (CQ) trend as the value of critical distance evaluated as 11.88 Å. Correlated color temperature (CCT) value for the optimized novel nanophosphor was ∼1714 K confirming their applications in the warm light-emitting diodes (LEDs).
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•Novel BaYZn3AlO7:Eu3+ nanophosphor is prepared via solution combustion method.•Crystal structure is investigated in detail using Rietveld refinement technique.•Prepared phosphors are explored by SEM, TEM, HRTEM and SAED measurements.•Judd-Ofelt study is carried out effectively.•Red light emission upon NUV excitation indicates their potential role in LEDs.
Synthesis of three new europium(III) complexes with 1,3-bis(4-methoxyphenyl)propane-1,3-dionato (HBMPD) ligand and ancillary ligands such as 2,2′-biquinoline (biq) or neocuproine (neo) has been ...reported in this report. The synthesized complexes were characterized by IR (infrared), 1H and 13C NMR (nuclear magnetic resonance) spectroscopy, CHN (carbon, hydrogen and nitrogen) elemental analysis, XRD (X-ray diffraction), TGA (thermogravimetric analysis) and photoluminescence (PL) spectroscopy. The emission spectra of europium(III) complexes displayed both the low intensity 5D1–3→7F0–3 transitions in 410–560nm blue-green region and high intensity characteristic 5D0→7F0–3 transitions in 575–640nm orange-red region correspond to the emission of ancillary ligands and europium ion respectively, which can lead to white luminescence due to integration of blue, green and red color emissions. The photoluminescence investigations indicate that the absorbed energy of the HBMPD ligand transferred to the central europium(III) ion in an efficient manner, which clearly explained by antenna effect. The excellent results of thermal behavior and photophysical properties like luminescence spectra, CIE (Commission Internationale Eclairage) chromaticity coordinates, luminescence decay curves and high quantum efficiency of the complexes make them a promising component of the white light-emitting diodes in display devices.
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•A new HBMPD ligand has been synthesized by an ecofriendly microwave irradiation.•Three new Eu(III) complexes have been prepared from HBMPD and ancillary ligands.•IR, NMR, CHN, XRD, TGA, UV–visible, PL techniques for the complexes•These complexes can be used as luminescent material in display devices.
► Eu/Tb-doped LaSrAl3O7 have been synthesized first time by combustion synthesis process. ► Synthesis process being in solution phase provide homogenous product. ► The process saves time as well as ...energy, so its economic one. ► The nanophosphors give deep red and green luminescent on excitation under UV. ► The optimal luminescent condition is at x=0.10 (La0.9Eu0.1SrAl3O7 and La0.9Tb0.1SrAl3O7).
The synthesis of LaSrAl3O7 doped with rare earth (RE) ions Eu3+ and Tb3+ by a single-step solution combustion method has been demonstrated in the present investigation. The structural, morphological and luminescent properties were characterized by XRD, FT-IR, SEM, TEM and PL spectroscopy. The XRD results suggest that LaSrAl3O7 crystallize in a single phase having tetragonal structure with space group P421m. The transmission electron microscope (TEM) and scanning electron microscope (SEM) analysis show that the sample is made up of tetragonal particles with the size between 38 and 78nm. The photoluminescence properties of the samples were investigated by excitation and emission spectra. Under UV excitation (265nm), LaSrAl3O7: Eu3+ shows dominant peak at 619nm in addition to other characteristic peaks of Eu3+. Under 233nm excitation, the characteristic emissions corresponding to 5D3–7FJ (J=4–6) and 5D4–7FJ (J=3–6) transitions in LaSrAl3O7: Tb3+ nanophosphors are observed. These results indicate that Eu3+ and Tb3+ activated LaSrAl3O7 nanophosphors can be applied for tunable solid state laser materials and plasma display panels.
