α-(Y,Gd)FS:Ce3+: a novel red-emitting fluorosulfide phosphor for solid-state lighting

Recent progress in luminescence tuning of Ce3+and Eu2+-activated phosphors for pc-WLEDs

“…Eu 2+ -Mn 2+ activated phosphors), red-green-blue phosphors, energy transfer, and mechanisms involved; and (d) new clues for designing novel high-performance phosphors for pc-WLEDs based on the available LED chips. 39,[41][42][43][44][45][46][47] The emphasis was also be placed on the relationships among crystal structures, luminescence properties, and device performances. He et al summarized the dependence of spectroscopic properties on composition for Eu 2+ , Ce 3+ or Yb 2+ -activated nitride and oxynitride phosphors based on a-SiAlON, b-SiAlON, oxonitridosilicates, nitridoalumosilicates and nitridosilicates.…”

“…In such cases, the Ce 3+ ion experiences a weaker crystal field splitting due to the expansion of YF 4 S 5 polyhedra in the Y 1.98 Ce 0.02 SrF 4 S 2 system; therefore, it is reasonable to observe the blue-shifted excitation and emission spectra. More evidence can be found about spectral tuning and the improvement of thermal stability based on the average lattice variation of the crystal structure in (Sr 2Àx Ba x )Ga 2 SiO 7 :Eu 2+ , 88 (Sr 1Àx Ca x )Si 2 O 2 N 2 :Eu 2+ , 89 Sr 4Àx Mg x Si 3 -O 8 Cl 4 :Eu 2+ , 90 (Ba 1Àx Sr x ) 9 Sc 2 Si 6 O 24 :Ce 3+ ,Li + , 91 A 3À2x RECe x Na x (BO 3 ) 3 (A = Sr, Ca; RE = Y, La), 92 a-(Y,Gd)FS:Ce 3+ , 42 and (Sr 1ÀxÀy Ca x -Ba y ) 2 Si 5 N 8 :Eu 2+ . [93][94][95] A schematic explanation is shown in Fig.…”

“…Typically, Ce 3+ or Eu 2+ doped sulfide and nitride phosphors have a longer emission wavelength than oxide phosphors and commonly give yellow-to-red emission. [41][42][43][44][45][46][47]93,95 If the activator ions were surrounded by anion groups, the higher charge density on the anion groups would exert the stronger nephelauxetic effect on activator ions. The charge density of some common anion groups is oxides 4 aluminates 4 silicates 4 borates 4 phosphates.…”

Enhanced Crystallinity and Luminescence Characteristics of Hexagonal Boron Nitride Doped with Cerium Ions According to Tempering Temperatures

“…This has been reported for organic dyes in the emission spectra [ 23 ]. Mirror symmetry is usually found for defect centers with weak Jahn-Teller interactions [ 24 ], which can be attributed to the substitution of Ce 3+ ions for B atoms in the hexagonal boron nitride framework, as shown in Raman spectroscopy. The broad PL spectrum of cerium-doped nitride materials is usually attributed to the 4f-5d excitation of Ce 3+ ions [ 25 ].…”

Facile combustion synthesis and photoluminescence properties of Ce3+ doped Sr2La8(SiO4)6O2 phosphors

“…It is wellknown that the 4f ground state of Ce 3+ shows a spin orbit splitting into two levels ( 2 F 5/2 and 2 F 7/2 ) and the theoretical energy difference of this splitting between 2 F 5/2 and 2 F 7/2 level is about 2000 cm À1 [4]. As the 4f-5d transitions are parity allowed, the 4f-5d transition of Ce 3+ ions can usually show superior absorption in the spectral region of 200-450 nm, therefore, many Ce 3+ ion doped phosphors for w-LEDs application have been developed [5][6][7][8][9].…”