A new phosphate phosphor K_5Y_(1-x)Sm_x(P_2O_7)_2 with bright orange-red emission and good thermal stability

摘要

These days, there is a great demand for the development of orange-red phosphors for temporary applications in the sides of lighting and display. In this work, we synthesized a fresh type of orange-red phosphor with K_5Y(P_2O_7)_2-doped Sm~(3+) by high-temperature solid-state method, and used powder X-ray diffraction (XRD) method to study the crystal structure of prepared samples. Due to the 4f→ 4f transition of Sm~(3+), when excited by near-UV light at 402 nm, K_5Y(P_2O_7)_2:Sm~(3+) phosphor emits orange-red light. The optimized Sm~(3+) concentration was found at 12%. Because of the concentration quenching, further increasing the Sm~(3+) concentration will reduce the intencity. The concentration quenching is originated from dipole-dipole interaction between Sm~(3+) ions. At 200 °C, the relative luminescence intensity is still about 70.3% of the intensity at 25 °C, meaning that K_5Y_(0.88)Sm_(0.2)(P_2O_7)_2 has good thermal stability. The chromaticity coordinates CIE were calculated to be (0.5813, 0.416), corresponding to orange-red color. All these results suggest that K_5Y_(0.88)Sm_(0.12)(P_2O_7)_2 is a promising orange-red phosphor.