Photoluminescence properties of a novel orange-red emitting Ba2CaZn2Si6O17:Sm3+ phosphor

Abstract

Novel orange-red emitting Ba2Ca1–xZn2Si6O17:xSm3+ (0.02≤x≤0.08) phosphors were synthesized using conventional solid-state reaction method under air atmosphere. The phase formation of the samples was characterized by powder X-ray diffraction patterns. Scanning electron microscopy (SEM) and photoluminescence properties were also investigated. The narrow excitation and emission spectra indicated the typical 4f-4f transitions of Sm3+. The dominant excitation line was around 405 nm attributed to 6H5/2→ 4F7/2 and the emission spectrum consisted of four emission peaks at 562, 600, 647, and 708 nm corresponding to the various transitions 4G5/2 to 6HJ (J=5/2, 7/2, 9/2 and 11/2) of the Sm3+ ions in the same order. The strongest emission band located at 600 nm was attributed to 4G5/2→6H7/2 transition of Sm3+, producing bright orange-red color emission. The optimal dopant concentration of Sm3+ ion in Ba2CaZn2Si6O17:xSm3+ phosphor was around 4 mol.% and the critical transfer distance (Rc) of Sm3+ was calculated to be 2.65 nm. Decay time varied with the Sm3+ concentrations in Ba2CaZn2Si6O17 phosphors. In addition, the Commission International del'Eclairagethe (CIE) chromaticity coordinates of Ba2Ca0.96Zn2Si6O17:0.04Sm3+ phosphor was located in the orange-red region (0.547, 0.450) and the correlated color temperature (CCT) was 2543 K. The present results indicated that Sm3+ activated Ba2CaZn2Si6O17 phosphors may be used as an orange-red emitting phosphor for near-ultraviolet (n-UV) based white light emitting diodes (WLEDs) applications.