In this work, six reddish orange Sm
3+
complexes were synthesized using organic ligand (
L
) and secondary ligands having hetero atoms by a one-step significant liquid-assisted grinding method and ...were characterized by spectroscopic techniques. The Urbach energy and band gap energy of the complexes were inspected by a linear fit. Using a least square fitting method, the Judd-Ofelt parameter and radiative properties were also determined. Thermal analysis, colorimetric analysis, luminescence decay time and anti-microbial properties of complexes were studied. The luminescence emission spectra of binary and ternary complexes displayed three characteristic peaks at 565, 603 and 650 nm in the powder form and four peaks at 563, 605, 646 and 703 nm in a solution phase due to
4
G
5/2
→
6
H
5/2,
4
G
5/2
→
6
H
7/2,
4
G
5/2
→
6
H
9/2
and
4
G
5/2
→
6
H
11/2
transitions respectively. The most intense transition in the solid phase (
4
G
5/2
→
6
H
7/2
) is accountable for orange color, and in the solution form, the highly luminescent peak (
4
G
5/2
→
6
H
9/2
) is responsible for reddish orange color of Sm
3+
complexes. PXRD and SEM analyses suggested that the complexes possess a nanoparticle grain size with crystalline nature. The decent optoelectrical properties of title complexes in the orangish-red visible domain indicated possible applications in the manufacturing of display and optoelectronic devices.
Six reddish orange Sm
3+
complexes were synthesized with the help of organic ligand and secondary ligands
via
one-step significant liquid-assisted grinding method and characterized spectroscopically.
Unique down-conversion virescent SrLaAlO
4
:Er
3+
nanocrystals were successfully fabricated by urea-assisted solution combustion route. Presence of tetragonal phase in doped samples SrLa
(1−
x
)
Er
x
...AlO
4
(
x
= 0.1–4.0 mol%) with a space group of 14/
mmm
(139) was investigated by powder X-ray diffractometry and Rietveld refinement analysis. Nanocubic crystals with their size ranging from 45 to 55 nm were displayed by scanning electron microscopy and transmission electron microscopy (TEM) techniques while high-resolution TEM highlighted the (105) crystallite plane by representing the resolved fringes of lattice. Nanocrystalline nature and the (101) crystal plane was depicted by selected area electron diffraction patterns of the powder sample. Qualitative as well as quantitative elemental composition of nanophosphors were investigated by mapping and spectra of energy dispersive X-ray analysis, respectively. On near UV excitation, photoluminescence emission spectra showed a prominent band of green color due to
4
S
3/2
→
4
I
15/2
transition (549 nm). Energy bandgap and refractive index of optimized sample were determined as 4.97 eV and 1.736, respectively, via diffuse reflectance spectra. Color chromaticity coordinates (0.1735, 0.6909) of SrLa
0.98
Er
0.02
AlO
4
nanophosphors verified their virescent emission with a color purity of 100% and were found to be consistent with the standard values of European Broadcasting Unit (EBU) as well as International Telecommunication Union, thus reflected their important role as the green component in the solid-state lighting devices, especially red–green–blue pc-white light-emitting diodes.
A series of luminescent europium(III) complexes have been synthesized by involving a β-diketone ligand 1-(5-chloro-2-hydroxyphenyl)-1,3-butanedione (CHPB) and four ancillary ligands. The luminescence ...properties of complexes suggesting good sensitization effect of ligand and favorable position of triplet state of ligand and coligand from the emitting levels of metal ion. The proposed energy transfer mechanism indicates high luminescence properties of complexes. The luminescence quantum efficiencies and Judd-Ofelt intensity parameter Ω2 of the complexes also determined.
Display omitted
•Complexes have been characterized by IR, 1H NMR and UV–visible spectroscopy.•The luminescence properties reveal higher luminescence of complexes.•The Judd-Ofelt intensity parameters of europium(III) complex have been studied.•Energy transfer mechanism has been investigated for these complexes.•The complexes possess higher thermal stability.
Luminescent trivalent europium(III) complexes Eu(CHPB)3·(H2O)2 (C1), Eu(CHPB)3·neo (C2), Eu(CHPB)3·batho (C3), Eu(CHPB)3·phen (C4) and Eu(CHPB)3·bipy (C5) have been synthesized by involving a β-diketone ligand 1-(5-chloro-2-hydroxyphenyl)-1,3-butanedione (CHPB) and four ancillary ligands like neocuproine (neo), bathophenanthroline (batho), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy). All the synthesized complexes C1–C5 were investigated by adopting various techniques such as elemental (CHN) analysis, 1H NMR spectroscopy, IR spectroscopy, UV–visible, thermal analysis (TG/DTG) and photoluminescence (PL) spectroscopy. The luminescence of complexes C1–C5 gets intensified suggesting a favorable position of triplet state of ligand and coligand from the emitting levels of metal ion. The luminescence quantum efficiencies and Judd-Ofelt intensity parameter Ω2 of the complexes also determined which advocate higher polarizable ligand field around central metal ion.
In this work, using Ba
2
Zn
2
La
4
O
10
(BZLO) as a structural model, a series of Er
3+
-doped nanophosphors were successfully developed through the most prominent solution combustion (SC) strategy. ...The phase purity, crystal structure, band gap studies and luminescence performance of the BZLO: Er
3+
(1–6 mol%) samples were investigated in detail. Based on the results of Rietveld refinement, the crystal structure of all Er
3+
-doped samples was determined to be a tetragonal type having
I4/mcm
symmetry (S.G. No. 140). The optical band gap value for Ba
2
Zn
2
La
3.88
Er
0.12
O
10
nanopowder was calculated to be 4.95 eV via diffuse reflectance (DR) studies. The morphology, crystallite size and chemical composition of Ba
2
Zn
2
La
3.88
Er
0.12
O
10
were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) analysis. Under 381 nm excitation, the photoluminescence (PL) spectra of Ba
2
Zn
2
La
4(1−
x
)
O
10
:4
x
Er
3+
(
x
= 1–6 mol%) nanophosphors showed characteristic emission peaks of Er
3+
ions positioned at 410 (
2
H
9/2
→
4
I
15/2
), 526 (
2
H
11/2
→
4
I
15/2
) and 549 nm (
4
S
3/2
→
4
I
15/2
, most prominent), respectively. Moreover, the optimum luminous composition was calculated as
x
= 0.03 due to the concentration quenching of the dipole–dipole interaction (d-d) type. The fluorescence decay lifetimes (in milliseconds) and quantum efficiencies of the
4
S
3/2
emission level in the Ba
2
Zn
2
La
4(1−
x
)
O
10
:4
x
Er
3+
(
x
= 1–6 mol%) series were also determined. Furthermore, all samples exhibited good CIE chromaticity coordinates located in the green region. All these results suggest the suitability of Ba
2
Zn
2
La
4
O
10
: Er
3+
nanophosphors as a green component in phosphor-converted white light-emitting diodes (pc-WLEDs).
Graphical Abstract
A series of Eu
3+
ion doped SrGdAlO
4
nanophosphors were prepared via solution combustion technique utilizing urea as a fuel. Structural properties of the tetragonal phase of the host/doped lattice ...belonging to the space group
I4
/
mmm
were characterized by powder X-ray diffraction (PXRD). Photoluminescence spectra, decay curves, UV–Visible diffuse reflectance spectra (UV–Vis DRS) and Judd–Ofelt analysis were utilized to characterize the photoluminescent properties. The radiative rates (
A
r
), branching ratios (
B
r
) and intensity parameters (
Ω
λ
) were estimated by Judd–Ofelt analysis. The optimal doping concentration of europium ions for SrGdAlO
4
host lattice was found to be 20 mol%, above which concentration quenching was observed due to dipole–dipole interactions. CIE coordinates values lie in the blue region at lower concentrations of Eu
3+
ions, which shifted towards white and then to reddish-orange region with higher concentrations of Eu
3+
ions, suggesting the color tunable property of the synthesized nanophosphors. Lower value of CCT and color tunable phenomenon proved it as potential candidate for warm white light and phosphor converted white light emitting diodes (Pc-WLEDs) applications. The optical band gap of both host lattice (5.50 eV) as well as of 20 mol% Eu
3+
doped SrGdAlO
4
nanophosphors (5.26 eV) lie in the range of semiconductors which enhanced their areas of applications.
Four red photoluminescent europium(III) complexes have been synthesized by using fluorinated carboxylate ligand, 1-(4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid as main ligand ...and bathophenanthroline, 1,10-phenanthroline and 2,2-bipyridyl as auxiliary ligands, through solution precipitation approach. The complexes possess an optimum thermal stability, which is sufficient for organic light emitting diodes fabrication. Under ultraviolet excitation, the complexes display an intense emission peak of europium ion, which makes them a promising red color emitter in display devices. Internal quantum efficiency, color coordinates, Judd-Ofelt parameters, and energy transfer mechanism have been explored. The investigated antimicrobial and antioxidant activity suggest that the synthesized complexes are potent antimicrobial and antioxidant agents.
Research Highlights
A new ligand L has been synthesized by an ecofriendly method.
Four Eu(III) complexes have been synthesized through a facile solution precipitation method by using ligand L and auxiliary ligands.
CHN, EDAX, IR, NMR, TG-DTG, DR, UV-vis, and PL spectroscopic techniques and antioxidant analysis are employed.
Potential candidate for display devices, laser devices, and antimicrobial agents.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Display omitted
•The research paper entitled “Probing into multifunctional deep orange-red emitting Sm3+-activated zincate based nanomaterials for wLED applications” highlights significant scopes in ...the field of luminescent nanomaterials. The main highlights are:•Novel Sm3+-activated BaLa2ZnO5 nanopowders have been fabricated via an energy saving urea combustion route.•In-depth down-conversion photoluminescence has been thoroughly scrutinized.•Rate of non-radiative energy-relocation as well as quantum-efficiency have also been evaluated.•Detailed bandgap as well as Urbach’s energy analysis has been conducted via a new empirical relation.•Potential candidate for warm-WLEDs, digital-signs, horticulture, bio-imaging, solar-cells and lasers.
Empirical-investigations on deep-orange-red emitting BaLa2ZnO5:Sm3+ phosphor-powders generated via low-temperature and environmentally-sound urea-combustion route, are presented. In-depth crystallographic-analysis, conducted via XRPD-facilitated-Rietveld-refinement, reveals their tetragonal-crystallinity. Emission-spectra under 413 nm-energization, yields an intense-band at 708 nm, thus imparting deep orange-red color to powders. The best luminous-performance has been marked at × = 0.02 Sm3+content. Also, various radiative-possessions including decay-time, intrinsic life-time, quantum-efficiency and relaxation-rate, which reflect their better luminance-potentiality, have been evaluated. Color-coordinates have realized their deep-orange radiance, which are proximate to those of AMBER LED-NSPAR 70-BS. All-in-all, present work successfully marked their utilization in high-performance warm-wLEDs, signage, bio-imaging, solar-cells and lasing applications.
Five luminescent ternary and one binary Europium(III) complexes were synthesised with β-keto acid as primary ligand and neocuproine(neo), 5,6-dimethyl-1,10-phenanthroline(dmph), ...4,7-diphenyl-1,10-phenanthroline (batho), 1,10-phenanthroline(phen), 2,2′-bipyridine (bipy) as ancillary ligands, via eco-friendly grinding method and were characterised through elemental analysis, UV–vis and IR spectroscopy,
1
H-NMR and
13
C-NMR spectroscopy. Their magnificent photophysical properties were studied by PL spectroscopy and numerically analysed by evaluating decay time of luminescence (τ), radiative (
A
rad
), non-radiative transition rate (
A
nrad
), luminescence efficiency (Ƞ) and Judd–Ofelt intensity parameters (Ω
λ
) for
5
D
0
→
7
F
2,4
transitions. The branching ratio of
5
D
0
→
7
F
2
transition in complexes (72–77%) makes it a potential laser emission transition. Optimum thermal stability, CIE colour coordinates value in deep red region and colour purity of nearly 90% (complex Eu6) make these complexes a promising candidate for red light emitting display devices. Energy transfer mechanism, optical band gap value and refractive indices were also explored for all complexes. The band gap energy of complexes lies within semiconductor range (2.87–3.83 eV), hence can have utility in lasers and military radars. Antioxidant and antimicrobial properties of all complexes were assessed. Complex Eu4 exhibited excellent antimicrobial activity, even better than standard drug, so the complex can be probed further as potent bactericidal agent.
Display omitted
•Characteristic cool white light emitting perovskite type SrLa2Al2O7:Dy3+ nanophosphors are fabricated.•Crystal structure along with phase purity is depicted by Rietveld Refinement ...Technique.•Nanophosphors show white emission under near ultraviolet excitation.•Energy band gap, decay lifetime and PL of the Dy3+ doped samples have been calculated.•CIE coordinates confirm their emission of cool white light.
Characteristic cool white light emitting perovskite type SrLa2Al2O7: Dy3+ nanophosphors were fabricated by solution combustion route. Presence of tetragonal phase with 14/mmm space group was investigated. Spherical shape with their size in range of 45–52 nm was observed. Qualitative and quantitative elemental composition was examined. On near UV excitation, Photoluminescence emission spectra showed blue and yellow bands at 483 and 575 nm due to 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transition respectively. CCT (8480 K) and CIE coordinates (0.302, 0.269) of SrLa1.94Dy0.06Al2O7 were found close to National Television System Committee white coordinates, thus proved them a potential candidate in single-phase phosphor converted WLEDs.
Novel cubic perovskite based orange red emissive Sr9(1-x)Al6O18: 9xSm3+ (0.001 ≤ x ≥ 0.04) nanocrystals were developed by environmentally benign and low temperature urea combustion method. Phase ...structure analysis showed the cubic structure with Pa3‾(205) space group. Scanning and transmission electron micrographs reported the agglomerated cubic morphology of the nanoparticles ranging from 40 to 60 nm. EDS (energy dispersive X-ray analysis) outcomes traced the adequate elemental composition of the spectral materials. The prepared nanomaterials displayed the fine orange red emission via 4G5/2 → 6H7/2 typical transition centered at 599 nm. Optical analysis asserted the wide band gap values of Sr8.82Sm0.18Al6O18 (3.77 eV) and Sr9Al6O18 (4.08 eV). Reliance of the emission intensity of developed nanophosphors on Sm3+ concentration claimed the Sr8.82Sm0.18Al6O18 as most desirable one with CIE coordinates (0.5833, 0.4159), 1747 K correlated color temperature (CCT) and color purity of 90.65%. These excellent results proved the relevancy of present nanophosphors as a novel promising material in the development of down conversion white LEDs. Also, the present research findings thus, can be well recurred to explore more about Sr9Al6O18 based spectral nanomaterials.
