High quantum efficiency red-emitting K2Gd(PO4)(WO4): Sm3+ phosphor: preparation, characterization and photoluminescence properties

Abstract

The Sm3+-activated K2Gd(PO4)(WO4) phosphors were prepared by a high temperature solid state reaction in air atmosphere and their photoluminescence properties were investigated in detail. These phosphors manifest the intense absorption under the 404 nm and give rise to bright red luminescence at the main emission peaks of 568, 604, 649 and 708 nm, corresponding to the 4G5/2→6HJ/2 (J = 5, 7, 9, 11) transitions of Sm3+ ions, respectively. The type of energy transfer between Sm3+ ions were affirmed as among nearest-neighbor ions and the critical distance Rc of concentration quenching was calculated to be 27.23 A. Furthermore, K2Gd0.98(PO4)(WO4):0.02Sm3+ was provided with superb color coordinate (0.5806, 0.4164) also high color purity. Temperature related photoluminescence spectra and decay curves indicated that the K2Gd0.98(PO4)(WO4):0.02Sm3+ possessed good thermal stability and quantum efficiency was determined to be 91.2%. These remarkable features revealed that the K2Gd(PO4)(WO4):Sm3+ phosphors are high-performance phosphors for applications of white light-emitting diodes.