A novel blue-emitting Sr2Gd8(SiO4)6O2:Bi3+ phosphor with oxyapatite structure

Abstract

A series of Sr2Gd8(SiO4)6O2 (SGSO):xBi3+ (x = 0.005, 0.007, 0.010, 0.030 and 0.050) phosphors were successfully synthesized by a high-temperature solid-phase route. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared (FT-IR), ultraviolet–visible diffuse reflectance (UV–Vis DR), photoluminescence excitation (PLE) and emission (PL) spectra were utilized to evaluate the samples. The characterization results show that the PLE spectra monitored at 440 nm present a broad band with the maximum at 315 nm. Besides, the pure SGSO possesses the space group P63/m crystal structure, in which the low symmetry C3 or Cs sites favor the transition from 3P1 to 1S0 of Bi3+, thus produce strong blue emission. According to the calculation of concentration quenching, the critical distance of energy transfer (ET) between adjacent Bi3+ is 23.48 Å, and it is concluded that the quenching mechanism is attributed to d-d interaction. Eventually, the International Commission on Illumination (CIE) chromaticity coordinates of phosphors are located in blue region, which can be suitable for practical application in the field of the white light-emitting diode (WLED) and plasma display panels (PDPs).