- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Novel highly luminescent double-perovskite Ca2GdSbO6:Eu3+ red phosphors with high color purity for white LEDs: Synthesis, crystal structure, and photoluminescence properties
摘要： High-efficiency red-emitting phosphors are required to fabricate high-performance white light-emitting diodes (LEDs). Herein, the novel highly efficient Eu3+-activated Ca2GdSbO6 double-perovskite red phosphors with good thermal stability toward warm-white LEDs were reported. A series of Ca2Gd(1-x)EuxSbO6 red phosphors with different Eu3+ doping concentrations (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) were synthesized by using high-temperature solid-state reaction method. Under the excitation of 396 nm near-ultraviolet light, these Ca2Gd(1-x)EuxSbO6 phosphors showed intense red emissions peaking at 612 nm due to the 5D0→7F2 transition of Eu3+ ions. The strongest luminescence intensity reached when Eu3+ doping concentration was x = 0.5, and the critical distance between Eu3+ activators was calculated to be 7.97 ?. The concentration quenching mechanism was due to the dipole-dipole interaction of Eu3+ ions. The CIE color coordinates of the optimal Ca2Gd0.5Eu0.5SbO6 phosphors were determined to be (0.6629, 0.3367), and the corresponding color purity reached about 94.9%. Importantly, the Ca2Gd0.5Eu0.5SbO6 phosphors revealed outstanding internal quantum efficiency of 73% and good thermal stability. The emission intensity of Ca2Gd0.5Eu0.5SbO6 phosphors at 423 K still remained about 73% of its initial value at 303 K. Finally, a prototype white LED device was fabricated by coating the phosphor blend of commercial blue-emitting BaMgAl10O17:Eu2+ and our as-prepared red-emitting Ca2Gd0.5Eu0.5SbO6 on a 395 nm LED chip. Under 20 mA driven current, the device showed bright warm-white light with CIE color coordinates of (0.3888, 0.3943), correlated color temperature of 3911 K, and color rendering index of 88.4. The results demonstrated that the developed novel red-emitting Ca2Gd0.5Eu0.5SbO6 phosphors could be used as potential color converters in white LEDs.
关键词： White LEDs,Photoluminescence,Ca2GdSbO6,Double-perovskite,Eu3+ ions,Red-emitting phosphors
更新于2025-09-23 15:19:57
-
Luminescence properties of novel red-emitting phosphors Ba3B6Si2O16: Eu3+ for near-UV excited LED
摘要： A novel Eu3+ doped Ba3B6Si2O16 red-emitting phosphor was synthesized by a high temperature solid state reaction and its luminescence properties were investigated. All the phosphors are pure phase of triclinic Ba3B6Si2O16 in structure. Under 393 nm excitation, Ba3B6Si2O16: Eu3+ phosphor exhibits intense red emissions due to the characteristic f–f transitions of Eu3+ with the strongest emission peaks at 613 nm. The optimum doping concentration of Eu3+ is 0.09 and the corresponding critical distance is estimated to be 23.9 ?. The emission intensity decreases with increase of Eu3+ ion concentration(x>0.09) due to dipole-dipole interactions among Eu3+. Ba3B6Si2O16: Eu3+ phosphor exhibits high color purity (92%), good thermal stability (the activation energy of 0.2121 eV) and high quantum efficiency (36.5 %) with CIE chromaticity coordinates of (0.6460, 0.3534). These results indicate that Ba3B6Si2O16: Eu3+ phosphor can be anticipated as a red emitting phosphor for near-UV pumped white LEDs.
关键词： luminescence property,Eu3+ ions,phosphors
更新于2025-09-23 15:19:57
-
Synthesis and photoluminescence properties of a new blue-light-excitable red phosphor Ca2LaTaO6:Eu3+ for white LEDs
摘要： In this paper, a series of Eu3+-activated double-perovskite Ca2LaTaO6 (abbreviated as CLT:xEu3+; x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8) red-emitting phosphors have been successfully synthesized via the conventional high-temperature solid-state reaction method. These samples were characterized by X-ray diffraction, Rietveld refinement, field-emission scanning electron microscope, elemental mapping, energy-dispersive spectrum, room-temperature photoluminescence, decay lifetimes, quantum efficiency, CIE color coordinates, and temperature-dependent emission spectra. Interestingly, under blue excitation into the 7F0→5D2 transition of Eu3+ at 466 nm, the CLT:xEu3+ phosphors could emit bright red light corresponding to the 5D0→7FJ (J = 1, 2, 3, 4) transitions. Their luminescence properties have been investigated as a function of the Eu3+ ions concentration. It was found that the CLT:0.4Eu3+ sample exhibited the strongest emission intensity, and the concentration quenching effect was caused by the dipole-dipole interaction among Eu3+ activators. Impressively, the emission intensity of the as-prepared CLT:0.4Eu3+ phosphors was about 4.3 times higher than the commercial Y2O3:Eu3+ red phosphors. Moreover, the CLT:0.4Eu3+ sample had excellent CIE color coordinates of (0.665, 0.334) and supereminent color purity of 95.3%. Notably, the study on temperature-dependent emission spectra of the CLT:0.4Eu3+ sample revealed its good thermal stability and color stability at high temperatures. These excellent photoluminescence properties of CLT:0.4Eu3+ phosphors indicated their promising application potential in white light-emitting diodes as blue-light-excitable red phosphors.
关键词： Ca2LaTaO6,White LEDs,Red-emitting phosphors,Eu3+ ions,Double-perovskite,Photoluminescence
更新于2025-09-23 15:19:57
-
Pulsed laser deposition of a ZnO:Eu3+ thin film: study of the luminescence and surface state under electron beam irradiation
摘要： A highly c-axis orientated Eu3+ doped ZnO (ZnO:Eu3+) thin film was successfully deposited by pulsed laser deposition in an oxygen working atmosphere. The structure, morphology, chemical analysis and luminescence properties of the sample were investigated. The effect of electron beam irradiation on the surface state, chemical and luminescence properties of the sample were studied. Successful incorporation of Eu3+ ions in the ZnO matrix was confirmed by X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) analysis. XPS measurements revealed traces of the divalent (Eu2+) on the film surface while the trivalent (Eu3+) oxidation state in the bulk of the film. XPS depth profile confirmed that the film contained excess oxygen throughout the film. The film exhibited exciton and defect emission of ZnO as well as 4f – 4f characteristic emission of Eu3+ ions superimposed on the defect emission when excited at 325 nm using a He-Cd laser. Whereas only 4f – 4f characteristic emission of Eu3+ ions was recorded when the film was excited at 464 nm and also when excited with the electron beam. XPS high resolution spectra of the O 1s peak confirmed the creation of new defects during electron beam irradiation. In general, ZnO:Eu3+ films show potential for applications as a source of red light in optoelectronic devices.
关键词： Degradation,PLD,ZnO thin film,Eu3+ ions,Cathodoluminescence,Red emission,Electron beam irradiation
更新于2025-09-19 17:13:59
-
Enhanced emission from thermally stable Eu3+ doped CaB2Si2O8 red phosphors via alkali metal modification for W-LEDs application
摘要： M+/Eu3+ (M = Li, Na, K) co-doped CaB2Si2O8 phosphors have been synthesized by a solid-state reaction approach. XRD measurements confirm that the phase purity of the CaB2Si2O8 host is maintained after the introduction of alkali metal ions and Eu3+ ions. The emission intensity of Eu3+ ions is enhanced by a factor of 1.75 and 1.55 with the incorporation of Li+ and Na+ ions, respectively, originating from the charge compensation and improved asymmetry in the crystal field, while the addition of K+ ions to the composition results in a decreased luminescence intensity due to the structural-defect-related quenching. Temperature dependent measurement reveals that the prepared phosphor exhibits excellent thermal stability with 81% at 423 K of the integrated emission intensity at 298 K. A white light-emitting diode (W-LED) device is fabricated based on the synthesized Eu3+ doped CaB2Si2O8 red phosphor modified by Li ions. All these results indicate that the synthesized phosphor is a promising red-emitting material for W-LEDs application.
关键词： Red phosphor,Eu3+ ions,W-LEDs,Alkali metal ions
更新于2025-09-16 10:30:52
-
Crystal structure and luminescence properties of the barium europium tetragermanate Ba2Eu2Ge4O13
摘要： The tetragermanate Ba2Eu2Ge4O13 was synthesized for the first time, and its structural and luminescent properties were examined. It crystallizes in a monoclinic system (space group C2/c, Z = 4) and its crystal structure incorporates a unique linear [Ge4O13]10– anion. The photoluminescence spectrum of the sample ( llllex = 280 nm) contains several intense peaks in the orange-red spectral range corresponding to the 4f–4f transitions in Eu3+ ions.
关键词： crystal structure,Ba2Eu2Ge4O13,luminescence,Eu3+ ions,tetragermanate
更新于2025-09-04 15:30:14