Divalent europium-doped nitride phosphors, Ca 1-x Eu x AlSiN 3 (x ) 0-0.2), were successfully prepared by the self-propagating high-temperature synthesis (SHS) by using Ca 1-x Eu x AlSi alloy powder as a precursor. The Rietveld refinement analysis was carried out on the CaAlSiN 3 host lattice to elucidate the luminescence properties of dopant Eu 2+ on the tetrahedrally coordinated site. For the Eu 2+ doped samples, strong absorption peaking at about 460 nm was observed on the excitation spectra, which matched perfectly with the current blue light of InGaN/GaN light-emitting diodes (LEDs). The optimized sample, Ca 0.98 -Eu 0.02 AlSiN 3 , gave the red emission peaking at 649 nm of which the intensity was competitive with the sample prepared from the metal nitride raw materials (Ca 3 N 2 , AlN, Si 3 N 4 , and EuN). The CIE chromaticity index (0.647, 0.347) with high color saturation indicated that it was a promising candidate as a redemitting phosphor for the InGaN/GaN-based down-conversion white LEDs for general illumination or displays.

Eu 2 + -doped ternary nitride phosphor, Sr2Si5N8:Eu2+, was prepared by the carbothermal reduction and nitridation method. The Rietveld refinement analysis showed that the single phase products were obtained. Two main absorption bands were observed on the diffuse reflection spectra peaking at about 330 and 420nm, so that the resultant phosphor can be effectively excited by InGaN light-emitting diodes. The emission peak position of (Sr1−xEux)2Si5N8:Eu2+ series varied from 618to690nm with increasing Eu2+ ion concentration. The redshift behavior of the emission band was discussed on the basis of the configuration coordination model.

Eu2+ ion-doped nitride phosphor, Ca2Si5N8:Eu2+, was synthesized by the carbothermal reduction and nitridation (CRN) method and the photoluminescence properties were characterized. It showed a broad absorption band between 250 and 550 nm which was efficiently excited by blue LEDs (400–470 nm) and a strong emission band peaking at 600 nm with a FWHM of 80 nm. The obtained phosphor provided saturated color chromaticity (0.589, 0.407) to generate warm-white light in phosphor-converted white LEDs.

A series of ternary nitride solid solutions with a general formula of ͑Sr 1−x Ca x ͒ 2 Si 5 N 8 /Eu 2+ ͑2 atom %͒ were synthesized by the carbothermal reduction and nitridation ͑CRN͒ method. The structure and luminescence properties were characterized for practical applications as a potential red phosphor for the phosphor-converted white light-emitting diodes ͑LEDs͒. The solid solutions were formed as the uniformly single phases with orthorhombic ͑ Pmn2 1 ͒ and monoclinic ͑Cc͒ symmetry at each end of ͑Sr 1−x Ca x ͒ 2 Si 5 N 8 , while in the range of 0.5 Ͻ x Ͻ 0.75, such solid solution phases coexisted. All of the obtained phosphors were well crystallized and the grains grew from 5 to 20 m with increasing Ca 2+ content. These phosphors showed broadened excitation spectra originated from the 4f 7 → 4f 6 5d transition of Eu 2+ ions, so that the intense orange-red emission bands were observed under the excitation of 380-470 nm corresponding to the output lights of near-UV or blue LEDs.