Near UV-pumped yellow-emitting Eu~(2+)-doped Na3K(Si_(1-x)Al_x)8O_(16±δ) phosphor for white-emitting LEDs

摘要

A novel yellow-emitting phosphor, Na3K(Si_(1-x)Al_x)8O_(16±δ):Eu~(2+), peaking at 555 nm was synthesized and evaluated as a candidate for white-emitting LEDs. The structure refinement, luminescence properties of Na3K(Si_(1-x)Al_x)8O_(16±δ):Eu~(2+) phosphors as well as their thermal quenching and the fabrication of white-emitting LEDs were for the first time investigated. By partially substituting Si"* with Al~(3+), the emission peak was shifted from 553 nm to 573 nm, giving a greenish yellow-yellow color, due to the splitting of the 5d energy level of Eu~(2+). By using a near-UV LED (395 nm) and a mixture of yellow-emitting Na3K(Si_(1-x)Al_x)8O_(16±δ):Eu~(2+) phosphor and blue-emitting BaMgAl_(10)O_(17):Eu~(2+) phosphor as light converters, we constructed an intense white-light-emitting LED. The white-light-emitting LED exhibited an excellent color-rendering index R_a of 90 at a correlated color temperature of 5952 K with ClE coordinates of (0.33, 0.29). The results of the white-emitting LED package combining 395 nm near UV chip with Y/B phosphors demonstrated the potential of the yellow-emitting Na3K(Si_(1-x)Al_x)8O_(16±δ):Eu~(2+) phosphor for UV LED apphcation.