Warm white light generation from single phase Sr3Y(PO4)3:Dy3+, Eu3+ phosphors with near ultraviolet excitation

Novel Sr3Y(PO4)3:Dy3+, Eu3+ (SYP:Dy3+, Eu3+) phosphors were synthesized by a standard solid-state reaction under an ambient air atmosphere and their structural and optical properties were investigated. XRD and diffuse reflectance spectra (DRS) were used to explore structural properties. The former showed that single phase phosphors were obtained and that the rare earth ions entered into the cubic host by substituting the smaller Y3+ ions and thereby enlarging the unit cell. The DRS indicated that the host has a direct bandgap of 4.5 eV. Under 393 nm excitation, a strong and stable warm white light emission with high color purity was achieved in SY0.92P:0.06Dy3+, 0.04Eu3+. The energy transfer from Dy3+ to Eu3+ ions was investigated and the related mechanism was discussed based on the optical spectra and emission decay curves. The thermal quenching of emission is similar to that of YAG:0.06Ce3+. The results show the single phase phosphor is potential in warm white LED.