Dazzling Red-Emitting Europium(III) Ion-Doped Ca₂LaHf₂Al₃O₁₂ Garnet-Type Phosphor Materials with Potential Application in Solid-State White Lighting

Abstract

Bright red-emitting phosphors with high color purity and high photoluminescence quantum yield (PLQY) are highly demanded for the fabrication of high-performance warmwhite light-emitting diodes (LEDs). Herein, we demonstrated a novel efficient Eu 3+ -activated Ca 2 LaHf 2 Al 3 O 12 garnet phosphor with excellent luminescence properties for near-ultraviolet (near-UV) excited warm-white LEDs. The Ca 2 LaHf 2 Al 3 O 12 :Eu 3+ phosphors exhibited an intense excitation spectrum in the near-UV region with a maximum around 394 nm, and they produced dazzling red luminescence peaking at 592, 614, 659, and 711 nm due to the 5 D 0 → 7 F J (J = 1−4) transitions of Eu 3+ ions when the excitation wavelength was set at 394 nm. Luminescent properties have been studied as a function of Eu 3+ doping concentration, and the highest emission intensity was achieved at 50 mol % Eu 3+ , while the dipole−dipole interaction brought the concentration quenching effect. The Ca 2 LaHf 2 Al 3 O 12 :50%Eu 3+ sample exhibited CIE chromaticity coordinates of (0.6419, 0.3575) with a color purity of 92.7%, and its PLQY was measured to be 64%. The thermal stability and activation energy of Ca 2 LaHf 2 Al 3 O 12 :50%Eu 3+ phosphors were also discussed and analyzed. Finally, we made a near-UV chip-based white LED device in which the Ca 2 LaHf 2 Al 3 O 12 :50%Eu 3+ phosphor was utilized as a red ingredient. A bright warm-white light emission was realized from this LED device under 80 mA driving current, accompanied by a high color rendering index (CRI) of 88.3, a low correlation color temperature of 3853 K, and good CIE chromaticity coordinates of (0.3909, 0.3934). These results revealed that these red-emitting Ca 2 LaHf 2 Al 3 O 12 :Eu 3+ phosphors have promising application prospect in near-UV-excited warm-white LEDs with high a CRI.

Thermal-stability synergy improvement of Sm3+ and Eu3+ in Ca3.6In3.6(PO4)6: the effect of local symmetry

“…The sharp peaks at 317 nm, 317 nm, 360 nm, 379 nm, 392 nm, 413 nm, and 463 nm belong to the electron transitions of the Eu 3+ ions 7 F 0 → 5 H 6 , 7 F 0 → 5 D 4 , 7 F 0 → 5 L 7 , 7 F 0 → 5 L 6 , 7 F 0 → 5 D 3 , and 7 F 0 → 5 D 2 , respectively. 23 Under 392 nm UV irradiation, emission peaks appear at 591 nm, 612 nm, 653 nm, and 702 nm, corresponding to the 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 , and 5 D 0 → 7 F 4 energy level transitions. 8 From Fig.…”

A Red‐Emitting La4Ti9O24:Eu3+ Phosphor Excited by Multi‐Wavelength for Healthy Lighting

“…The three main characteristic peaks of Eu 3+ ions, which are corresponding to 5 D 0 → 7 F J ( J = 1, 2, 4) transitions, are located at 592, 616, and 709 nm. [ 23,24 ] It is discovered that the line profile remains unchanged even though the various excitation wavelengths result in various emission intensities. The emission intensities are almost unchanged as the excitation wavelengths of 393 and 464 nm.…”

Thermal Quenching Mechanism of Metal–Metal Charge Transfer State Transition Luminescence Based on Double-Band-Gap Modulation

“…Compared with traditional luminescent materials, new fluorescent materials based on rare-earth luminescent materials are widely used in daily lighting, electronic display, solid-state lasers, and fluorescent thermometry sensors on account of the energy conservation, greenness, and high efficiency. − However, the sustainable supply and high cost of rare-earth elements limit their development. , Therefore, some transition-metal elements and main group metal elements have received great attention as substitutes for rare-earth elements. Among the numerous main group metal elements, Bi 3+ impresses owing to its rich emission colors in flexible crystal structures containing the entire visible-light region by ultraviolet (UV) and near-ultraviolet (n-UV) excitation .…”