A new phosphate phosphor K5Y1−xSmx(P2O7)2 with bright orange-red emission and good thermal stability

Abstract

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 K5Y(P2O7)2-doped Sm3+ 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 Sm3+, when excited by near-UV light at 402 nm, K5Y(P2O7)2:Sm3+ phosphor emits orange-red light. The optimized Sm3+ concentration was found at 12%. Because of the concentration quenching, further increasing the Sm3+ concentration will reduce the intencity. The concentration quenching is originated from dipole–dipole interaction between Sm3+ ions. At 200 °C, the relative luminescence intensity is still about 70.3% of the intensity at 25 °C, meaning that K5Y0.88Sm0.12(P2O7)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 K5Y0.88Sm0.12(P2O7)2 is a promising orange-red phosphor.