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

G.Annadurai¹，S.Masilla Moses Kennedy¹，V.Sivakumar²

1. Department of Physics, S.S.N. College of Engineering, Rajiv Gandhi Salai2. Saveetha Engineering College

摘 要：Novel orange-red emitting Ba₂Ca_1–xZn₂Si₆O₁₇:x Sm³⁺（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 ⁶H_5/2→ ⁴F_7/2 and the emission spectrum consisted of four emission peaks at 562, 600, 647, and 708 nm corresponding to the various transitions ⁴G_5/2 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 ⁴G_5/2→⁶H_7/2 transition of Sm³⁺, producing bright orange-red color emission. The optimal dopant concentration of Sm3+ ion in Ba₂CaZn₂Si₆O₁₇:x Sm³⁺ 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 Ba₂ CaZn₂Si₆O₁₇ phosphors. In addition, the Commission International del’Eclairagethe（CIE） chromaticity coordinates of Ba₂Ca_0.96Zn₂Si₆O₁₇:0.04Sm³⁺ 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.

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