Structure and luminescence properties of green-emitting NaBaScSi₂O₇:Eu²⁺phosphors for near-UV-pumped light emitting diodes

Abstract

Green-emitting phosphor Eu 2+ doped NaBaScSi 2 O 7 was synthesized by a solid-state reaction, and the photoluminescence properties were investigated in conjunction with a structural analysis. The crystallographic occupancy of Eu 2+ in the Sc silicate NaBaScSi 2 O 7 matrix was studied based on the Rietveld refinements results and the crystal chemistry rules. The optimum concentration of Eu 2+ in the NaBaScSi 2 O 7 phosphor was about 10 mol%, and the concentration quenching mechanism was verified to be the dipole-dipole interaction. Upon excitation at 365 nm, the composition-optimized NaBaScSi 2 O 7 :Eu 2+ exhibited strong green light peaking at 501 nm with the CIE chromaticity (0.0706, 0.5540) and a high internal quantum efficiency of about 65%. The thermally stable luminescence properties were also studied and compared with those of the commercial green phosphors. A white light emitting diode (w-LED) lamp was finally fabricated by using the present green phosphor and the commercial blue and red phosphors, which exhibited a high color rendering index (R a ) of 86.5 at a correlated color temperature of 2528 K with CIE coordinates of x ¼ 0.353, y ¼ 0.324. These results suggest that NaBaScSi 2 O 7 :Eu 2+ is a potential green phosphor candidate for near-UV-pumped w-LEDs.

Synthesis of Sr2Si5N8:Ce3+ phosphors for white LEDs via efficient chemical vapor deposition

“…As per the estimation done in the literature, these three conditions were calculated based on Eq. (1), respectively35. Compared with the calculated values obtained from Si 4+ sites (1200–1250 nm), it can be concluded that the Sr 2+ sites can act as the favorable cation sites for Ce 3+ ion.…”

Novel cyan‐emitting KBaScSi2O7:Eu2+ phosphors with ultrahigh quantum efficiency and excellent thermal stability for WLEDs

“…The phase composition and crystal structures of the prepared KBSS:0.002Eu 2+ sample is verified by XRD and analyzed by the Rietveld refinement as presented in Figure A. Since the KBSS is a new host, the related structural information is deficient, thus, we used the reported crystallographic data of KSrScSi 2 O 7 as the initial structure model . The compound KBSS belong to the family of KMRESi 2 O 7 (M = Ba 2+ , Sr 2+ and RE = Y 3+ , Sc 3+ ), which has a monoclinic structure with the space group of P 2 1 / n .…”

“…Thus, they are very suitable for the basic research and investigate their potential application . Chen et al reported a novel blue‐emitting KSrScSi 2 O 7 :Eu 2+ phosphor with high efficiency and excellent thermal stability, which mainly ascribed to the rigid network with the enriched environments of Sc and weak electron–phonon coupling strength . This result further confirms that Sc silicate would be a suitable phosphor matrix for WLEDs.…”

Eu2+‐Doped Yellow‐Emitting CsBaB3O6 Glass‐Ceramic Prepared by Melt Quenching and Re‐Crystallization Method

“…36 As shown in Fig. 37 Another Eu 3+ center appeared in heavily Eu-doped CsBaB 3 O 6 should be induced by the possible defects with the increase of Eu 2+ doping in the lattices. In heavily Eu-doped CsBaB 3 O 6,, three Eu 2+ together with one Eu 3+ center can be identified in the lattices.…”