Enhanced luminescence and thermal stability of (Sr,Ca)AlSiN3:Eu2+ via superficial organic carbon modification

The Eu2+-activated nitride phosphors have been widely used in solid-state lighting, but the applications in high-power white-light-emitting diodes (wLEDs) field require higher thermal stability of luminescent materials. The oxidation of Eu2+ and the damage of nitride host in the Eu2+-activated nitride phosphors are the two crucial reasons for the luminescence loss while operating. A superficial organic carbon modification is performed on the red-emitting (Sr,Ca)AlSiN3:Eu2+ phosphor via the incorporation of organic carbon by solution mixing and thermal post-treatment under the N-2-H-2 atmosphere. After the superficial organic carbon modification, the oxidation of Eu2+ and the formation of impurity phases on the phosphor surface are effectively reduced. When the superficial organic carbon modified sample was treated in the 2 wt.% sucrose solutions, the relative brightness is strengthened by 2.15%, the thermal quenching characteristic is improved by 8.9% at 300celcius, and the aging test results show an excellent thermal stability. All above indicate that the superficial organic carbon modification is a promising technique to enhance the thermal stability of analogous Eu2+-activated nirtide phosphors.