Samarium doped apatite-type orange-red emitting phosphor Ca5(PO4)2SiO4 with satisfactory thermal properties for n-UV w-LEDs

A novel single-phase Sm3+ activated Ca-5(PO4)(2)SiO4 phosphor was successfully fabricated via a conventional solid-state method, which can be efficiently excited by near ultraviolet (n-UV) light-emitting chips. The crystal structure and luminescence properties were characterized and analyzed systematically by using relevant instruments. The Ca-5(PO4)(2)SiO4:Sm3+ phosphor shows an orange-red emission peaking at 600 nm under the excitation of 403 nm and the optimal doping concentration of Sm3+ is determined to be 0.08. The critical distance of Ca-5(PO4)(2)SiO4:0.08Sm(3+) is calculated to be 1.849 nm and concentration quenching mechanism of the Sm3+ in Ca-5(PO4)(2)SiO4 host is ascribed to energy transfer between nearest-neighbor activators. The decay time of Ca-5(PO4)(2)SiO4:0.08Sm(3+) is determined to be 1.1957 ms. In addition, the effect of temperature on the emission intensity was also studied, 72.4% of the initial intensity is still preserved at 250 degrees C, better thermal stability compared to commercial phosphor YAG:Ce3+ indicates that Ca-5(PO4)(2)SiO4:0.08Sm(3+) has excellent thermal stability and active energy is deduced to be 0.130 eV. All the results demonstrate that orange-red emitting Ca-5(PO4)(2)SiO4:0.08Sm(3+) phosphor exhibits good luminescent properties. Owing to the excellent thermal quenching luminescence property, Ca-5(PO4)(2)SiO4:0.08Sm(3+) phosphor can be applied in n-UV white light emitting diodes and serve as the warm part of white light. (C) 2019 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.