A novel efficient red-emitting K7SrY2B15O30: Eu3+ phosphor with non-concentration quenching and robust thermal stability for white LEDs

Abstract

Inhibiting energy migration between Eu3+ ions in a fixed host to get higher doping concentration is a permanent topic. Herein, a novel non-concentration quenching red-emitting K7SrY2-2xB15O30: xEu3+ (0.1 ≤ x ≤ 1.0) phosphor was synthesized via high-temperature sintering method. XRD measurement, Rietveld refinement results, and radius percentage deviation calculation demonstrated the phase purity and the occupation preference of Eu3+ ions. With continuously increasing doping Eu3+ ions, the absence of concentration quenching could be explained by long distance between two Eu3+ (7.012 Å) and the K7SrEu2B15O30 could exhibit striking photoluminescence performance with the highest emission wavelength centered at 617 nm. Meanwhile, under the radiation of 393 nm, the high internal quantum efficiency ( ∼ 78.71 %), excellent color purity ( ∼ 88.32 %) and robust thermal stability whose emission intensity at 140 °C could still reach ∼ 97.31 % could guarantee its potential application. When coating BaMgAl10O17: Eu2+, (Ba, Sr)2SiO4: Eu2+, and K7SrEu2B15O30 on a near-ultraviolet chip, the bright white light with a low correlated color temperature of 4211 K and CIE color coordinates of (0.3675, 0.3556) could be obtained. Taking the analytic results above, the non-concentration quenching K7SrY2B15O30: Eu3+ compound has great potential to act as a candidate for red-emitting phosphors in solid-state lighting field.