Synthesis and photoluminescent properties of orange-emitting Sm3+- activated KPb4 (PO4)3 phosphor for LEDs

A series of Sm3+-doped KPb4(PO4)(3) phosphors have been successfully synthesized by high-temperature solidstate reaction method, and the structure, morphology and luminescent properties were investigated. The SEM images suggest that the prepared phosphor has an irregular morphology with a diameter of about 10 similar to 20 mu m. Under near-ultraviolet (NUV) light (404 nm) excitation, all prepared phosphors ICPb4-xSmxP3O12 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.15, 0.2, 0.3, 0.4 and 0.5) show the characteristic f -> f emission bands of the Sm3+ activator. And the emission intensities have an upward trend with increasing the Sm3+ concentration when x is lower than 0.1. By monitoring 598 nm emission, the excitation spectrum of KPb3.9Sm0.1(PO4)(3) contains a series of sharp bands in the range of 250 similar to 500 nm, which matches well with the NUV LED chip. The CIE coordinates of KPb3.9Sm0.1(PO4)(3) phosphor was evaluated to be (0.5714, 0.4253), corresponding to orange color with a high color purity of about 90%.