Crystal structure and luminescence property of a novel blue-emitting Cs_(2x)Ca_(2x)Gd_(2(1?x))(PO_4)_2:Eu~(2+) (x = 0.36) phosphor

摘要

A novel blue-emitting double-phosphate phosphor Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2:Eu~(2+) was synthesized by the sol–gel method, and the structure and luminescence properties were investigated in detail. The crystal structure and chemical composition of Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2 matrix was analyzed and determined based on Rietveld refinements and phase and chemical composition analysis. The composition-optimized Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2:Eu~(2+) exhibited strong blue light, peaking at 462 nm upon excitation at 365 nm with the CIE coordinates of (0.139, 0.091). The quenching concentration of Eu~(2+) in the Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2 phase was about 0.01 and attributed to the dipole–quadrupole interaction. The thermally stable luminescence properties, fluorescence decay curves and diffuse reflectance spectra of Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2:Eu~(2+) phosphors are also discussed, all of which indicate that the Cs_(0.72)Ca_(0.72)Gd_(1.28)(PO_4)_2:Eu~(2+) phosphor is a promising phosphor for application in white-light UV LEDs.