Synthesis of Ca_(2-x)Al_2SiO_7∶ Dy_x~(3+) White-Emitting Phosphor by Gel-Combustion-Molten Salt Method

The Ca2-xAl2SiO7∶ Dy3 +x( x =0.01,0.02,0.03,0.04,0.05) light emitting phosphor was synthesized by gel-combustion-molten salt method,and the effect of Dy3 +concentration on the emission spectrum intensity of Ca2-xAl2SiO7∶ Dy3 +xwas discussed. The synthesized sample were characterized by Xray diffraction( XRD),field emission scanning electronic microscopy( FE-SEM) and spectrophotofluorometer. The results show that the Ca1. 97Al2SiO7∶ Dy3 +0. 03 sample have a tetragonal cacoclasite structure and average size is about 0. 9-1 μm,and the excitation spectra consist of some narrow peaks which are assigned to the electronic transitions(6H15 /2→6P3 /2) at 321 nm,(6H15 /2→6P7 /2) at 345 nm,(6H15 /2→6P5 /2) at 363 nm,(6H15 /2→4F7 /2) at 384 nm,(6H15 /2→4G11 /2) at 425 nm,(6H15 /2→4I15 /2) at 452 nm and(6H15 /2→4F9 /2) at 470 nm,and the sample excitation consist of the blue light emission at 477nm(4F9 /2→6H15 /2) and yellow light emission at 580 nm(4F9 /2→6H13 /2),CIE1931 chromaticity coordinates are( x = 0. 3017,y = 0. 3011) and it is very near to ideal white in chromaticity diagram( x =0.333,y =0.333),and the concentration quenching is appearing when Dy3 +doping concentration is greater than 0. 03 and it is caused by the electric d-d interaction mainly.