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Investigations on RE(TTA)3tppo (RE=Eu/Sm/Eu0.5 Sm0.5) rare earth β-diketonate complexes for OLEDs and solid state lighting
摘要： Rare earth hybrid organic β-diketonate complexes of Eu(III), TTA and tppo; Eu(TTA)3tppo, Sm(TTA)3tppo and Eu0.5Sm0.5(TTA)3tppo [Eu: europium, Sm: samarium, TTA: Thenoyl Trifluoro Acetone, tppo: Triphenylphosphine oxide] were synthesized by solution technique, maintaining pH 7. X-ray diffractogram of all the complexes revealed their crystalline nature. TGA curves infer their thermal stability to be in the range of 2300C - 2600C. The optical energy band gap of these complexes was found to be in the range of 3.08 to 3.20 eV. When RE(TTA)3tppo complexes were excited at 377 nm, 382 nm and 382 nm respectively, the emission spectra portrays red emission, peaking at 616 nm, 645 nm and 616 nm in solid state, while in solvated state, hypsochromic shift (shift toward lower wavelength) was noticed. CIE co-ordinates and color correlated temperature (CCT) of the complexes tuned according to their emission wavelength. These investigations provide a good deal of information regarding their suitability for the fabrication of red to blue tunable light emitting organic light emitting diodes (OLEDs), panel displays and solid state lighting panels on flexible substrates.
关键词： Samarium,flat panel displays,Rare earth β-diketonates,europium,OLED devices,solid state lighting
更新于2025-09-16 10:30:52
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Development of Eu3+ doped boro-tellurite oxyfluoride glass and their Judd-Ofelt analysis for red laser gain medium application
摘要： This paper investigated the physical, optical, luminescence and radiative properties of Eu3+ doped borotellurite oxyfluoride glass with composition (30-x)TeO2-30B2O3-10ZnF2-30BaO-xEu2O3 where x are 0.05, 0.10, 0.50, 1.00 and 1.50 mol%. The glass samples were fabricated by melt and quenching method. The physical and optical properties were investigated from density, molar volume and refractive index. Meanwhile absorption spectra that show several transitions in the ultraviolet to near infrared region interpret the optical properties of the glass sample. The emission spectra of glass sample were measured under excited ?ex = 394 nm. The highest peak of emission spectra occurs in 1.5 mol% of Eu2O3 due to 5D0→7F2 transition centered at 613 nm. The emission intensity was increased by the addition of Eu2O3 from 0.05 mol% to 1.5 mol%. In addition, Judd-Ofelt (JO) theory was used to define the radiative properties and lasing potential of the glass sample. The value of JO parameter ?2, ?4, ?6 was calculated and compared with literatures. Other radiative properties including experimental (fexp) and calculated (fcal) oscillator strengths, stimulated emission cross-sections (σ), radiative transition probability (AR), experimental and calculated branching ratios (?R) of glass sample were determined and discussed in term of red laser gain medium application.
关键词： Oxyfluoride glass,Europium,Gain medium
更新于2025-09-16 10:30:52
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Luminescence varied by selective excitation in Eu3+,Tb3+-doped LiSrPO4 phosphors for W-LEDs applications
摘要： Tb3+ and Eu3+-doped LiSrPO4 (LSPO) were produced via a modified sol-gel route. Structural and optical characterization was performed by X-ray diffraction (XRD) and photoluminescence spectroscopy (PL), respectively. The results reveal that the presence of dopants has an effect on the LSPO structure. PL spectra of the LSPO:Tb, Eu (LSPOTE) phosphor consisted of major emission lines associated with 5D3,4-7FJ (J = 3, 4, 5 and 6) and 5D0-7FJ (J = 0, 1, 2, 3 and 4) transitions of Tb3+ and Eu3+ ions, respectively. A change in emission spectra was observed when the excitation wavelength was changed. Under middle-ultraviolet excitation (227 nm), the Tb3+ and Eu3+-doped LiSrPO4 phosphor exhibited white emission. The results suggest that the LiSr0.97PO4:Tb0.01,Eu0.02 phosphors prepared in the present work could be used in combination with AlGaN chips to fabricate white LEDs.
关键词： Terbium,Lithium strontium orthophosphate,Europium,White LEDs
更新于2025-09-16 10:30:52
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Europium-doped boro-telluro-dolomite glasses for red laser applications: Basic insight into spectroscopic traits
摘要： Naturally abundant minerals and lanthanide-doped synthetic boro-tellurite networks have become prospective efficient laser hosts because of the synergy between them. Driven by this idea, Eu3+-doped boro-telluro-dolomite (BTD) glasses were prepared via the melt-quenching method. The spectroscopic traits of as-quenched samples were analyzed though experimental and theoretical studies. The result from the derivation of absorption spectral fitting (DASF) model demonstrated the direct allowed transition in the glasses. Moreover, the photo-luminescence spectra of the sample containing 1.0 mol% of Eu3+ (BTD1.0Eu glass) revealed a prominent red peak at 611 nm (assigned to 5D0 → 7F2 transition in Eu3+ ion) with a large stimulated emission cross section (7.15 × 10?22 cm2) and a high luminescence branching ratio (61.5%). Furthermore, the attained CIE color coordinates (0.637, 0.363), which lie near the standard red hue (0.67, 0.33), together with high quantum efficiency (92.7%) affirmed the effectiveness of BTD1.0Eu glass as a potential red laser host.
关键词： Boro-telluro-dolomite glasses,Red emission,Europium ions,Judd–ofelt analysis,Radiative parameter,Optical band-gap energy
更新于2025-09-16 10:30:52
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Luminescent europium-doped titania for efficiency and UV-stability enhancement of planar perovskite solar cells
摘要： Perovskite solar cells (PSCs) have demonstrated high power conversion efficiencies (PCEs) but poor stability against ultraviolet (UV) irradiation. Here, we report a one-pot synthesized luminescent europium-doped titania (Eu-TiO2) via chemical-bath deposition at low-temperature (70 oC) for planar PSCs, which enables simultaneous efficiency and UV-stability enhancement. We show that the Eu-TiO2 could effectively convert damaging UV photons into useful visible luminescence for additional light harvesting. A more optimal energy band alignment at the Eu-TiO2/perovskite interface leads to facilitated charge extraction and suppressed non-radiative recombination. The use of Eu-TiO2 in PSCs results in increased photocurrent and open-circuit voltage, yielding an enhanced PCE of 21.40% with relative to pristine TiO2 device (19.22%). More importantly, the Eu-TiO2 devices exhibit remarkably improved UV stability, retaining 75% of the initial PCE after exposing to UV illumination for 500 hours, while the devices with pristine TiO2 lost the majority of their original PCEs in 150 hours. As a proof-of-concept, we further demonstrate the scalability of our method by fabricating a large-area Eu-TiO2 film of 64 cm2 showing excellent uniformity.
关键词： band alignment,planar perovskite solar cells,down-shifting,europium-doped titanium dioxide,UV stability
更新于2025-09-12 10:27:22
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Excellent ambipolar gas sensing response of Eu[Pc(OC4H9)8]2/acidified multiwalled carbon nanotubes hybrid at room temperature
摘要： A new hybrid material has been developed by mixing a sandwich-type double-decker, Eu[Pc(OC4H9)8]2 = 2,3,9,10,16,17,23,24-octabutoxyphthalocyaninate] with acidified multiwalled carbon nanotubes (aMWCNTs) through non-covalent interactions. The UV-vis spectrum, X-ray diffraction and scanning electron microscope have been employed to reveal the J-aggregate mode and optimized morphology of Eu[Pc(OC4H9)8]2 molecules in the Eu[Pc(OC4H9)8]2/aMWCNTs hybrid material. The gas-sensing devices based on this hybrid material are fabricated by a simple solvent-processing quasi-Langmuir–Sh?fer (QLS) progress. The n-type and p-type response is shown by the Eu[Pc(OC4H9)8]2/aMWCNTs hybrid film at room temperature. The detection limit of the hybrid for ammonia and nitrogen dioxide gas is 0.5 ppm and 0.3 ppm, respectively.
关键词： phthalocyanine,gas sensing,multiwall carbon nanotubes,ambipolar organic semiconductor,europium complex
更新于2025-09-12 10:27:22
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Divalent europium-doped near-infrared-emitting phosphor for light-emitting diodes
摘要： Near-infrared luminescent materials exhibit unique photophysical properties that make them crucial components in photonic, optoelectronic and biological applications. As broadband near infrared phosphors activated by transition metal elements are already widely reported, there is a challenge for next-generation materials discovery by introducing rare earth activators with 4f-5d transition. Here, we report an unprecedented phosphor K3LuSi2O7:Eu2+ that gives an emission band centered at 740 nm with a full-width at half maximum of 160 nm upon 460 nm blue light excitation. Combined structural and spectral characterizations reveal a selective site occupation of divalent europium in LuO6 and K2O6 polyhedrons with small coordination numbers, leading to the unexpected near infrared emission. The fabricated phosphor-converted light-emitting diodes have great potential as a non-visible light source. Our work provides the design principle of near infrared emission in divalent europium-doped inorganic solid-state materials and could inspire future studies to further explore near-infrared light-emitting diodes.
关键词： divalent europium,Near-infrared luminescent materials,4f-5d transition,light-emitting diodes,phosphor
更新于2025-09-11 14:15:04
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Pulsed Laser Deposition of Rocksalt Magnetic Binary Oxides
摘要： Magnetic binary oxides with the rocksalt structure constitute an important class of materials for potential applications as electronic or electrochemical devices. Moreover, they often become a theoretical playground, due to the simple electronic and crystal structures, in the quest for novel phenomena. For these possibilities to be realized, a necessary prerequisite would be to grow atomically ordered and controllably-strained binary oxides on proper substrates. Here we systematically explore the use of pulsed laser deposition technique (PLD) to grow three basic oxides that have rocksalt structure but different chemical stability in the ambient atmosphere: NiO (stable), MnO (metastable) and EuO (unstable). By tuning laser fluence FL, an epitaxial single-phase NiO thin-film growth can be achieved in a wide range of growth temperatures 10 ≤ TG ≤750 °C. At the lowest TG, the out-of-plane strain raises to 1.5%, which is five times higher than in NiO film grown at 750 °C. MnO thin films that had long-range order were successfully deposited on the MgO substrates after appropriate tuning of deposition parameters. The growth of MnO phase was strongly influenced by FL and the TG. EuO films with satisfactory quality were deposited by PLD after oxygen availability had been minimized. Synthesis of EuO thin films at rather low TG = 350 °C prevented thermally-driven lattice relaxation and allowed growth of strained films. Overall, PLD was a quick and reliable method to grow binary oxides with rocksalt structure in high quality that can satisfy requirements for applications and for basic research.
关键词： Thin films,Nickel monoxide,Long-range ordered,Manganese monoxide,Europium monoxide,Strain engineering
更新于2025-09-11 14:15:04
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Fabrication of Luminescent Antireflective Coatings with CaMoO4:Eu3+/Ag Composite Structure
摘要： Highly transparent and luminescent CaMoO4:Eu3+/Ag composite films were fabricated on glass substrates as multifunctional antireflective (AR) coatings. The films were deposited through a combination of a sol–gel dip-coating technique and a hot water treatment. With the addition of an aluminum source in coating solutions, the sol–gel-derived films underwent a remarkable microstructural change during the hot water treatment due to the reaction between an amorphous alumina phase and water. This change brought both an antireflective effect (suppression of Fresnel reflection) and luminescence enhancement (suppression of total internal reflection) to the films. The introduction of Ag nanoparticles into the films further increased luminescence intensity without losing the antireflective effect.
关键词： calcium molybdate,silver nanoparticles,antireflective coatings,europium,nanocomposite,sol–gel method,photoluminescence
更新于2025-09-11 14:12:44
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3D water-stable europium metal organic frameworks as a multi-responsive luminescent sensor for high-efficiency detection of Cr <sub/>2</sub> O <sub/>7</sub><sup>2?</sup> , MnO <sub/>4</sub><sup>?</sup> , Cr <sup>3+</sup> ions and SDBS in aqueous solution
摘要： A microporous europium metal–organic framework (Eu-MOF), namely, {[Eu3(bpydb)3(HCOO)(OH)2(DMF)]·3DMF·2H2O}n (1) with asymmetric trinuclear metal clusters extended by 4,40-(4,40-bipyridine-2,6-diyl) dibenzoic acid has been synthesized via the solvothermal method. PXRD of 1 confirms that it possesses excellent water stability and pH stability. The photo-luminescence properties of 1 exhibit effective recognition of Cr2O72?, MnO4?, and Cr3+ ions and SDBS. Furthermore, a wide linear range, high quenching constant and a low detection limit reveal that 1 can potentially act as a luminescence-based sensor for quantitative and highly sensitive detection of Cr2O72?, MnO4?, and Cr3+ ions as well as SDBS in aqueous solutions. To the best of our knowledge, the detection limit of 1 is the lowest value reported for Ln-MOF-based luminescent sensors to detect Cr2O72? ions (0.5 mM) in aqueous solutions. The use of a rare earth fluorescent probe for detecting MnO4? ions is not common. It is the first time that Ln-MOF as a fluorescence probe is used for detecting SDBS. Moreover, fluorescent-based test papers of 1 have also been prepared, which can be helpful to develop visual detection for Cr2O72?, MnO4?, and Cr3+ ions as well as SDBS in daily applications.
关键词： aqueous solution,SDBS,MnO4?,luminescent sensor,Cr2O72?,europium metal–organic framework,Cr3+ ions
更新于2025-09-10 09:29:36