A series of high-efficient red-emitting phosphors K2Y(WO4)(PO4):Eu3+ have been successfully synthesized by conventional solid-state reaction, and its photoluminescence (PL) properties have been investigated. The phosphors can be excited efficiently by NUV light, then exhibit strong red emission with quantum efficiency of 70.5%. The concentration quenching takes place at relatively high concentration of Eu3+ (x = 0.70), which is further confirmed by the variation of decay curves of the entitled phosphors. Judd-Ofelt analysis ascertains the presence of Eu3+ in a highly asymmetric environment. The phosphor exhibits good thermal stability (92.5% at 100 degrees C and 84.1% at 180 degrees C). The red LED prototype fabricated by opyimized-composition K2Y(WO4)(PO4):0.70Eu(3+) phosphor and 395 nm-emitting InGaN chips exhibit bright red emission. The results indicate that the K2Y(WO4)(PO4):Eu3+ phosphors are promising red phosphors for NUV LED. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.