Tunable luminescence of (Sr <sub/>1?x</sub> Ca <sub/>x</sub> ) <sub/>1.97</sub> MgSi <sub/>2</sub> O <sub/>7</sub> :0.03Eu ²⁺ solid solution phosphors for cirtopic LEDs

摘要： In order to realize the 490 nm single-peak emission for cirtopic light-emitting diodes (LEDs), a series of iso-structural (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ (x = 0, 0.2, 0.3, 0.4, 0.8, 1) phosphors with melilite structure have been prepared by traditional solid-state reaction. The x-ray Diffraction (XRD) patterns and regular lattice parameters confirm the formation of (Sr1?xCax)2MgSi2O7 solid solution. Broad band excitation spectra were observed in the ultraviolet region of these phosphors. The photoluminescence spectra of (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ solid solution phosphors give continuously tunable emission from 466 [Sr2MgSi2O7:Eu2+, (x = 0)] to 527 nm [Ca2MgSi2O7:Eu2+, (x = 1)]. Phosphors with an illuminating centre at 486 and 490 nm were obtained when adjusting the x value to 0.3 and 0.4 respectively. By measuring the quantum efficiency (QE) and contrasting with the spectral sensitivity function of cirtopic, (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ (x = 0.3, 0.4) phosphors have potential value in cirtopic vision.