A Novel Warm White Light Phosphor Ca2Al2SiO7:Dy3+ for White Light-Emitting Diodes

The white light emitting phosphor Ca2Al2SiO7:Dy3+ was synthesized by a conventional high-temperature solid-state method. X-ray diffraction and photoluminescence spectra were used to characterize the as-synthesized phosphor. Strong excitation peaks of Ca2Al2SiO7: Dy3+ were found around 350-370 nm, which matched well with the UV LED chip. Under 350 nm excitation, Ca2Al2SiO7: Dy3+ phosphor can exhibit an intense warm white emission by combining the two emission peaks locating at blue region (485 nm) and yellow region (575 nm), attributed to the characteristic F-4(9/2)-H-6(15/2) and F-4(9/2)-H-6(13/2) transition of Dy3+. The critical doping content of Dy3+ is 7%, and the intensity of the emission increased proportionally as the Dy3+ concentration increased until it was reached at 7%. When the doping concentration occurred from 7% to 9%, the luminescence intensity gradually reduced. Moreover, The CIE coordinates and the correlated color temperature (CCT) are also investigated in this work. The result shows that the optimum phosphor Ca1.93Al2SiO7:0.07Dy(3+) exhibits excellent color purity with chromaticity coordinates of (0.375, 0.391) and the CCT of 4231 K and could be considered as potential research value on white-LEDs.