Narrow-band red phosphors of high colour purity based on Eu³⁺-activated apatite-type Gd_9.33(SiO₄)₆O₂

Abstract

A series of new red phosphors based on apatite-type gadolinium silicate host, Gd9.33-xEux(SiO4)6O2 (0.03 < x < 1.87), has been synthesised and analysed. The phosphors show excellent chemical and thermal...

Deep‐Red Ca3Al2Ge3O12:Eu3+ Garnet Phosphor with Near‐Unity Internal Quantum Efficiency and High Thermal Stability for Plant Growth Application

“…The comparison of the luminescence thermal stability at 150 °C and the IQE of the representative Eu 3+ doped phosphors with Ca 3 Al 2 Ge 3 O 12 :Eu 3+ are given in Figure 3c and Table S3 (Supporting Information). [ 18,30,40,42,65–71 ] Among them, Ca 3 Al 2 Ge 3 O 12 :40%Eu 3+ exhibits a high IQE of up to 98.4% and an excellent thermal stability (78.8%@150 °C). These remarkable photoluminescence properties enable the Ca 3 Al 2 Ge 3 O 12 :Eu 3+ phosphor to show promising application in phosphor‐convert LEDs.…”

“…The IQE value of the Ca 3c and Table S3 (Supporting Information). [18,30,40,42,[65][66][67][68][69][70][71] 3 and the chromaticity coordinate of (0.3147, 0.3189). The luminescence spectra and the corresponding chromaticity parameters of the fabricated white LED under different currents are given in Figure S6 and Table S4 (Supporting Information).…”

“…Furthermore, the intensive 5 D 0 → 7 F 4 transition can be assigned to the coordination polyhedron of EuOx distorted from a cubic geometry to the square antiprism, where the 5 D 0 → 7 F 2 transition is forbidden due to the point group selection rule, while the 5 D 0 → 7 F 4 transition is allowed. [18,[41][42][43] Generally, most of the reported Eu 3+ -doped phosphors emit red light with the 5 D 0 → 7 F 2 transition as the dominant one. To date, only a handful of Eu 3+ -doped phosphors can emit intense deep-red luminescence at around 707 nm ascribed to an intense 5 D 0 → 7 F 4 transition, represented by LaPO 4 :Eu 3+ , [44] Na 3 YSi 3 O 9 :Eu 3+ , [45] Ca 2 Ga 2 SiO 7 :Eu 3+ , [46] Bi 2 SiO 5 :Eu 3+ , [47] and Ca 2 Ga 2 GeO 7 :Eu 3+ .…”

A novel red-emitting phosphor with an unusual concentration quenching effect for near-UV-based WLEDs

“…As is well known, excellent red-emitting phosphors are needed for preparing WLEDs with a high CRI and low CCT. [46][47][48] A higher red-to-orange ratio (the ratio of the intensities of the 5 D 0 -7 F 2 and 5 D 0 -7 F 1 transitions) suggests a better red emission, therefore, the improvement of the red-to-orange ratio is an efficient way to obtain a superior red emission. In GGTO: xEu 3+ , it is easy to find that the proportion of red emission (ascribing to 5 D 0 -7 F 2 transition) increases continuously with the increase of Eu 3+ concentration, while the orange emission (ascribed to 5 D 0 -7 F 1 transition) presents an opposite trend in Fig.…”

Structural and Luminescence Behavior of Nanocrystalline Orthophosphate KMeY(PO4)2: Eu3+ (Me = Ca, Sr) Synthesized by Hydrothermal Method

“…The second method is to mix the blue, green, and red emissions generated from three or two blended powders. Rare-earth-doped (RE) phosphates are a good candidate for the formation of white LEDs due to their good physical and chemical stability, low cost of substrates, and reduced preparation temperatures compared to silicates, aluminosilicates, or nitrates [8][9][10][11][12][13].…”