K2Y(WO4)(PO4): Tm3+, Dy3+: a potential tunable single-phased white-emitting phosphor under UV light excitation

A white-emitting K2Y(WO4)(PO4): Tm3+, Dy3+ phosphor has been successfully prepared by conventional high-temperature solid-state reaction. X-ray diffraction and photoluminescence spectra were used to characterize the as-synthesized phosphors. The results show that all samples crystallize in an orthorhombic crystal system with a space group of Ibca (73). Under the excitation at 292 nm, the un-doped sample presents a self-illumination feature, which should result from the crystal host excitation or molecular transitions within the WO42− group. Upon 360 or 350 nm excitation, the Tm3+or Dy3+ single-doped K2Y(WO4)(PO4) samples can emit an intense blue and white light with the optimal concentration 1% and 5%, respectively. In order to inquiry the interactions of Tm3+ and Dy3+, a series of co-doping samples were prepared and by the analyses of excitation and emission spectra and decay times, we carefully investigated whether or not the energy transfer occurs between Tm3+ and Dy3+ in the host K2Y(WO4)(PO4). In addition, the color coordinate of as-obtained samples pumped by ultraviolet light are also clearly displayed in this work. Furthermore, with the increase in temperature, KYWP: 0.05Dy3+ presents satisfactory thermal stability. All the results indicate that the single-composition phosphor could have a promising application in the area of white light emitting diodes.