White light emission in host-sensitized Dy3+-single-doped NaIn(WO4)2 phosphors

A novel white NaIn1−x(WO4)2: xDy3+ (x=0, 0.02, 0.04, 0.06 and 0.08) phosphors in pure phase were prepared via high temperature solid-state reaction, and luminescent properties of the phosphors were investigated. The crystal structure of the phosphor was characterized by powder X-ray diffraction, and the spectroscopic properties of Dy3+-doped NaIn(WO4)2 were investigated by diffuse reflectance spectra, photoluminescence emission and photoluminescence excitation spectroscopy. Those spectra illustrated that the Dy3+-doped NaIn(WO4)2 phosphors could be efficiently excited by the host-sensitized excitation in the spectral range of 280–350 nm, and the host-sensitized excitation is more efficient than the Dy3+ excitation. The 6 mol% Dy3+ doping concentration in NaIn(WO4)2 is optimum, and the luminescence concentration quenching occurs beyond the 6 mol% concentration. The concentration quenching mechanism could be attributed to the dipole–dipole interaction between the Dy3+ ions. The CIE color coordinate of the 6 mol% Dy3+-doped NaIn(WO4)2 is (0.319, 0.325). The present work suggests that Dy3+-doped NaIn(WO4)2 could be a promising host-sensitized phosphor applied in white LEDs, and white emission can be obtained by combining the blue host emission with the yellow Dy3+ emission.