Towards single broadband white emission in Rb0.5K1.5CaPO4(F, Cl): Eu2+ via selective site occupancy engineering for solid-state lighting applications

Abstract

• A single white emission phosphor is obtained by site-selective occupancy engineering. • The substitution of F by Cl effectively controlled the selective occupation of Eu 2+ . • The R 0.5 K 1.5 CPOF 0.8 Cl 0.2 : 0.5%Eu 2+ has a broad FWHM and excellent thermal stability. • The wLED fabricated with 365 nm chip and the phosphor has high CRI and suitable CCT. Phosphors with single broadband white emission are ideal for solid-state lighting applications. However, achieving single broadband white emission in a single activator doped single component phosphor is very challenging. Herein, by introducing a small amount of Cl - ions into the Rb 0.5 K 1.5 Ca 0.995 PO 4 F: 0.5%Eu 2+ phosphor, we effectively controlled the selective occupation of Eu 2+ ions at Ca sites or K/Rb sites and obtained a single broadband white emission phosphor Rb 0.5 K 1.5 Ca 0.995 PO 4 F 0.8 Cl 0.2 : 0.5%Eu 2+ . The luminescence of this phosphor presents a desirable full width at half maximum (274 nm) and excellent thermal stability (81.9%@150 °C of the integrated emission intensity at room temperature). A white light-emitting diode with high color rendering index (Ra = 93.6) and suitable correlated color temperature (4163 K) was successfully fabricated using Rb 0.5 K 1.5 Ca 0.995 PO 4 F 0.8 Cl 0.2 : 0.5%Eu 2+ phosphor and a 365 nm chip, demonstrating the significant application value of as-prepared phosphors in the field of solid-state lighting. This work provides an effective design strategy for the development of single activator doped single component white light emitting phosphors, which will facilitate the development of related phosphors in the future.