Synthesis, structural and luminescence studies of Bi~(3+) co-doped MgTiO_3:Eu~(3+) nanophosphor

摘要

MgTiO_3:Eu~(3+) (1-11 mol %) and Bi~(3+) co-doped nanophosphors (NPs) were synthesized by a facile low temperature self processing combustion technique. Powder x-ray diffraction (PXRD) studies confirm pure single rhombohedral phase (space group R-3) with average crystallite size in the range 20-40 nm and the same was checked by transmission electron microscopy (TEM). Photoluminescence (PL) of MgTiO_3 doped with Eu~(3+) (1-11 mol %) cations exhibit intense red emission upon 395 nm NUV excitation and all the emission peaks may be attributed to the 4f-4f intra shell transitions (~5D_0→~7F_(j=0,1,2,3)) of Eu~(3+) cations due to energy transfer from the host to the Eu~(3+) ions, the cause which is responsible for this are the degree of intrinsic defects (O_2-vacancies). PL studies revealed that a small quantity of Bi~(3+) (1 mol %) ions was effective for charge compensation as well as creation of lattice defects to enhance the luminescence emission. The CIE chromaticity co-ordinate values (x, y) were very close to red color. The results support that, the phosphor is a candidate for display and wLEDs.