Five novel bright orange color emitting Sm(III) complexes (C1-C5) have been synthesized via energy efficient and cost effective solution precipitation method with 5-phenyl 2-furoic acid as primary ...organic sensitizer and nitrogen donor neocuproine, 2, 2- bipyridyl, bathophenanthroline, and 1,10-phenanthroline as secondary ligands. All the newly synthesized metal complexes are thoroughly characterize to examine the appropriateness of the organic ligand for the sensitization process. All the outcomes of the various advanced and fundamental spectroscopic techniques validate the bonding of carboxylate group with the Sm(III) ion. The luminescence spectra reflects the dominance of magnetic dipole transition which designate the occurrence of harmonized chemical environment in the coordination sphere which is further validated by enhanced values of intensity ratio. These complexes possess suitable thermal stability with excellent photoluminescent features as confirmed by thermogravimetric analysis and photoluminescence studies. The luminescence lifetime of samarium complexes C2-C5 is relatively long due to the synergistic effect presented by ancillary ligands. The emission color of the synthesized complexes show shift from orange to bright orange red color which is displayed through CIE color coordinates.
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.
The present research work entails the synthesis of one binary and four ternary red light−emitting Eu (III)‐based complexes with 3‐benzylidene‐2,4‐pentanedione as the main ligand and ...1,10‐phenanthroline, bathophenanthroline, neocuproine, and 4,4′‐′dimethyl‐2,2′‐′bipyridyl as auxiliary ligands. The metal–organic framework of the series was elucidated using energy dispersive X‐ray analysis, elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance. This Eu (III) series exhibits optimum thermal stability, making them a promising candidate for organic light‐emitting diodes. On the basis of emission spectra, their optical parameters such as nonradiative and radiative decay rates, luminescence decay time, intrinsic quantum efficiency, and Judd–Ofelt intensity parameter were determined. The monocentric luminescence and Judd–Ofelt parameters reveal the absence of symmetry around the europium center. CIE chromaticity coordinates, correlated color temperature values, color purity, and asymmetric ratios authenticate the color coordinates of the complexes in red region. Optical band gap values lie within the range of wide band gap semiconductors, indicating their utilization in military radars and biological labeling.
In this work, we have reported five red light emitting Eu(III) complexes utilizing bidentate ligand and auxiliary ligands. The synthesized complexes are analyzed by EA, FT‐IR, NMR, UV, DR, PL and TG analysis. PL and CIE investigation of the complexes depicts the red coloured emission. The energy transfer phenomenon reveals the efficient complexation of ligands with Eu(III) ion.
Our present technological society needs the assistance of lanthanide luminescence in almost every field to meet the global energy demands. In present research work we have synthesized five (one ...binary and four ternary) 5-(4-methylphenyl)-2- furoic acid based Eu(III) complexes with ancillary ligands, namely, aqua (H
2
O), neocuproine (neo), 2, 2’-bipyridyl (bipy), bathophenanthroline (batho) and 1, 10-phenanthroline (phen). The spectroscopic analysis and photophysical features are characterized by the use of different investigative techniques. All the findings obtained from EDAX, elemental (CHN) analysis, FT-IR, NMR, UV–visible spectroscopy declared the coordination of ligand binding sites with the europium ion. These Eu(III) complexes possess good thermal stability and excellent optoelectronic features as predicted with the help of TGA and PL analysis. Diffuse reflectance spectral studies confirm their applications in the wide band gap semiconductors. The Judd–Ofelt analysis and monoexponential behavior of lifetime reveals the existence of asymmetric and single local environment around europium ion. All the complexes show sharp red emission validated by CIE color coordinates, color purity, asymmetric ratio and CCT values. SEM analysis tells that the bulk of these complexes comprised of spherical shaped particles with uniform distribution.
To illuminate the zone of organic light‐emitting diodes, a novel series of four red luminescent europium complexes, one binary (C1) and three ternary (C2–C4), of 5‐phenyl 2‐furoic acid was ...synthesized with 2,2′‐bipyridyl (bipy), bathophenanthroline (batho) and 1,10‐phenanthroline (phen) as ancillary ligands and characterized by adopting various analytical techniques. All the findings of energy‐dispersive X‐ray spectroscopy, elemental (CHN) analysis, Fourier transform infrared, nuclear magnetic resonance, and ultraviolet–visible spectroscopy confirmed the coordination of ligand binding sites with the europium ion. To evaluate the thermal stability, thermogravimetric/difference thermogravimetric measurements were taken that revealed that the synthesized complexes were stable up to 245°C. Diffused reflectance studies indicated that these complexes had potential for their use in wide band‐gap semiconductors, as all the four complexes showed metal‐centred luminescence as a characteristic red emission peak that was observed at 613 nm under the excitation wavelength of 330 nm. The internal quantum efficiencies and luminescence lifetime of complexes were predicted using Judd–Ofelt and photophysical data. The monoexponential luminescence decay and Judd–Ofelt analysis suggested the presence of a single and asymmetric chemical environment in the coordination sphere of the europium metal. Commission International de l'Eclairage colour coordinates, correlated colour temperature values, and colour purity of the complexes validated their red emission in the visible region.
In this research work we reported a novel series of four complexes consisting of one binary and three ternary complexes emitting red light that were successfully synthesized using chelating bidentate ligand and ancillary ligands. Complexes were analyzed systematically using CHN, IR, NMR, UV, TG, DR, and PL studies. The PL study reflected the red‐coloured emission of the complexes in the visible region. The energy transfer mechanism approved the effective complexation of the ligands with metal ions.
Five luminescent europium (III) carboxylate complexes have been synthesized by using ligand 3-isopropylpyrazole-5-carboxylic acid as primary ligand and 4,4'-dimethyl-2,2'-bipyridyl, 2,2'-bipyridyl, ...5,6-dimethyl-1,10-phenanthroline and 1,10-phenanthroline as secondary ligands and characterized through various techniques. These complexes exhibit excellent thermal stability and characteristic europium centered photoemission spectra under the excitation of ultraviolet light. Luminescence decay curves, Judd-Ofelt analysis, internal quantum efficiency and energy transfer mechanism have also been discussed. The color coordinates and color purity are calculated to investigate red emission of the complexes. The study results reveal that these complexes can be potentially used as red light emitting materials in various optoelectronic devices.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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•Five new europium (III) complexes are synthesized and characterized by adopting various advanced techniques.•TG/DTG analysis reveals the thermal stability of complexes up to ...245 °C.•The PL spectra of the complexes are devoid of any ligand fluorescence and phosphorescence confirms efficient energy transfer.•From their emission spectra colour coordinate values and Judd- Ofelt intensity parameters are calculated and analyzed.•The colour coordinate values of all complexes depict pure red emission.
Europium complexes attracted generous interest devoted to their red colored emission for illuminising the grounds of organic light-emitting diodes. In this series, five europium complexes (C1-C5) have been synthesized with Ethyl 4-(4-methoxyphenyl 2, 4-dioxobutanaote) (dioxoester) as primary ligand and neocuproine (neo), 2, 2′-bipyridyl (bipy), bathophenanthroline (batho) and 1, 10-phenanthroline (phen) as ancillary ligands. All these complexes are characterized by adopting various investigative techniques. They show europium-centered luminescence as a characteristic red colored emission peak at 618 nm due to (5D0-7F2) -transition. The luminescence lifetime and internal quantum efficiencies of complexes are predicted by using photophysical data and Judd-Ofelt analysis. The monoexponential behavior of the decay curve suggests the presence of a single chemical atmosphere in the inner coordination sphere of the europium ion. TG/DTG analysis reveals the thermal stability of complexes up to 245 °C. The CIE color coordinates, color purity and asymmetric ratio of complexes confirm the emission in the red region of the visible spectrum.
Preparation and optoelectronic features of five new samarium (III) binary and ternary complexes with 5-(4-methylphenyl)-2- furoic acid (L) are reported in the solid state. The structures of the ...complexes Sm(L)3.H2O (C1), Sm(L)3neocuproine (C2), Sm(L)3bipyridyl (C3), Sm(L)3bathophenanthroline (C4) and Sm(L)3 phenanthroline (C5) are analyzed by elemental analysis, EDAX, FTIR, 1H NMR and thermogravimetric analysis (TGA). The photo-emission spectra exhibit well-defined narrow emission peaks that originates from 4G5/2→6HJ (J = 5/2, 7/2, 9/2) transitions of the samarium ion. All complexes exhibit good thermal stability with attractive photophysical features. The CIE color coordinates based on photoemission spectra are approximate with the National Television Standard Committee (NTSC) standard value for orange color. Especially the ternary complexes C2–C5 displayed enhanced photoluminescence intensity and longer luminescence lifetime value as compared to the binary complexes C1, with the introduction of the electronic donating 4-methyl group and the enlarged π-conjugated phenyl group. All the results indicate that these complexes are promising candidate as orange component in fabrication of organic light emitting diodes (OLED).
•Five new samarium (III) complexes are synthesized and characterized.•TG/DTG analysis reveals the thermal stability of complexes up to 151 °C.•Emission spectra consists of three well identified peaks of Sm (III) ion.•Complexes show bright orange emission as validated by chromaticity characteristics.
To improve current multiphase white light emitting diodes (WLEDs), a novel series of five complexes consisting of one binary and four ternary complexes that emitted cool white light was successfully ...synthesized using a chelating tetradentate ligand and auxiliary ligands, i.e. 5,6‐dimethyl‐1,10‐phenanthroline, 1,10‐phenanthroline, 4,4′‐dimethyl‐2,2′‐bipyridyl, and 2,2′‐bipyridyl. The series was examined structurally using elemental analysis, Fourier transform infrared spectroscopy, energy dispersive X‐ray analysis, ultraviolet–visible spectroscopy, and proton nuclear magnetic resonance spectroscopy. These complexes had the appropriate thermal stability required for the generation of white organic LEDs (WOLEDs). Dysprosium (III) (Dy3+) ion complexes demonstrated the characteristic emission peaks of blue colour at 482 nm and yellow colour at 572 nm, respectively, when excited using near ultraviolet light. Band gap, refractive index, and decay lifetime of the optimized samples were recorded as 2.68 eV, 2.12, and 1.601 ms, respectively. Correlated colour temperature value (7875 K), Commission International de l'Eclairage coordinates (0.300, 0.294), and colour purity (21.04 × 10−2) of the optimized complex were near to those of white illuminants as defined by the National Television System Committee. These complexes had promise as commercial LEDs for the advanced optoelectronics devices, especially as WOLEDs for illumination applications.
In this research work we reported a novel series of five complexes consisting of one binary and four ternary complexes that emitted cool white light and that were successfully synthesized using chelating tetradentate ligand and auxiliary ligands. The complexes were analyzed systematically by different techniques. Photoluminescence studies as well as colour purity and correlated colour temperature values confirmed cool white emission of the complexes in visible region. The energy transfer mechanism confirmed effective complexation of ligands with metal ions.
The ongoing ambitious progression in the illumination sector to design the iconic WLEDs has bestowed an impetus to manufacture novel and eco-friendly nanophosphors (NPs). In this pursuit, we have ...presented cool white light-emitting single-phase crystalline Dy
3+
-doped Ca
9
Y(PO
4
)
7
i.e., CYP:Dy
3+
nanophosphors synthesized via a facile, economical, and non-toxic solution combustion (SC) technique. The crystal structural details regarding phase formation and crystallite size of CYP:Dy
3+
was inferred using powder x-ray diffraction (PXRD), which suggests the structures are in a rhombohedral phase with the R3c space group. The Kubelka–Munk model was used to evaluate the optical band gap of 4.18 eV, thus revealing their desired optical quality and semiconductor nature. Transmission electron microscopy (TEM) showed agglomerated particles with irregular dimensions with an average size ranging from 40 nm to 65 nm. Photoluminescence studies indicated the emission of visible photons under high energy irradiation with the bands at
4
F
9/2
→
6
H
13/2, 15/2
, due to intra-configurational transitions of Dy
3+
ions. The phosphor was located in the white region with the Commission Internationale de I'Eclairage (CIE) chroma coordinates of (0.295, 0.336). Thus, the presented work carves an avenue for the synthesis of single-phase nanophosphors with economical and environmental advantages, along with a proposal to boost the advancement in WLEDs relevant to industrial prospects, thus generating more revenue.
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