Sol-gel auto-combustion synthesis and luminescence properties of GdCaAl3O7: RE3+ (RE=Eu, Tb, Eu@Tb) phosphors for near-ultraviolet light-triggered indoor illumination

Abstract

The color-tunable GdCaAl3O7: RE 3+ (RE=Eu, Tb, Eu@Tb) phosphors were synthesized via an ultrafast sol-gel auto-combustion synthesis method. The XRD (X-ray diffraction) patterns confirmed the forming of GdCaAl3O7 tetragonal phase, and the SEM (Scanning electron microscopy) images indicated that the obtained products presented honeycomb-like structure due to the gas releasing during the auto-combustion process. The EDS (Energy dispersion spectra) results suggest that Eu 3+ and Tb 3+ were well incorporated into the host matrices of GdCaAl3O7. The luminescent properties, concentration quenching mechanism, energy transfer mechanism, luminescent dynamics, thermal stability and product practicability of GdCaAl3O7: R 3+ (RE=Eu, Tb, Eu@Tb) phosphors were investigated systematically. All the GdCaAl3O7: RE 3+ (RE=Eu, Tb, Eu@Tb) products presented the characteristic emission of doped RE 3+ . Using GdCaAl3O7: 50% Tb 3+ @3.0% Eu 3+ as yellow-emitting phosphors in combination with commercial BAM: Eu 2+ blue-emitting phosphors and a NUV chip can successfully package a warm white LED device with high color rendering index (CRI, 86.3) and low correlated color temperature (CCT, 3348 K) that was very suitable for near-ultraviolet light-triggered indoor illumination.

Eu3+-Activated Alkali Rare-Earth Double-Tungstate Nanoparticles for Near-Ultraviolet-Light-Triggered Indoor Illumination

“…For example, the NaGdF 4 :Eu 3+ phosphor exhibited visible red light with admirable color purity; 8 good thermal stability and good resistance to saturation and degradation were observed in the CsBaB 3 O 6 :Eu 3+ phosphor; 9 and the red-emitting GdCaAl 3 O 7 :Eu 3+ phosphor has good color rendering capacity, showing potential in warm white LED applications. 10 However, Eu 3+ -doped phosphors inevitably suffer from low color purity, poor thermal stability, and low quantum yield, restricting their general development. Therefore, it is of vital significance to explore novel red-emitting phosphors with excellent thermal stability, low cost, and high quantum yield.…”

Nanotechnologies in ceramic electrochemical cells

“…The sol–gel self-combustion method is an effective and economical synthesis technique for the preparation of aimed products and has been frequently used for the syntheses of a series of electrolyte and electrode materials for CECs, 128,129 photocatalysts, 130 phosphors, 131 for electrical or magnetic engineering applications. 132 It is used for the synthesis of nano-sized and homogeneously distributed materials by mixing diverse elements at the atomic level.…”

Structural and photoluminescent features of Eu3+ activated single‐phase niobate phosphor for lighting applications

“…However, such WLEDs have high correlated color temperature and low color rendering index (CCT and CRI) as a result of the congenital absence of red light 2,3 . To obtain efficient WLEDs with proper CCT and CRI, research work has been recently focused on the method employing n‐UV/UV emitting LED source coated with multiple (red, green, and blue) color emitting single‐phase phosphors 4,6 . Existing red‐emitting phosphors were still limited to Eu 3+ induced sulfide‐based host like (Ca, Sr) S: Eu 2+ and Y 2 O 2 S: Eu 3+ , which are unstable and decompose at high temperatures 3,4 .…”

“…2,3 To obtain efficient WLEDs with proper CCT and CRI, research work has been recently focused on the method employing n-UV/UV emitting LED source coated with multiple (red, green, and blue) color emitting single-phase phosphors. 4,6 Existing red-emitting phosphors were still limited to Eu 3+ induced sulfide-based host like (Ca, Sr) S: Eu 2+ and Y 2 O 2 S: Eu 3+ , which are unstable and decompose at high temperatures. 3,4 As a result, novel and stable red phosphors with high efficiency were instantly required.…”