Deep-red emission of Mn4+ and Cr3+ in (Li1−xAx)2MgTiO4 (A=Na and K) phosphor: Potential application as W-LED and compact spectrometer. Issue 9 (15th June 2017) - Chen, Tiejin
Abstract: Mn 4+ doped and Mn 4+ /Cr 3+ co-doped alkali metal titanate phosphors have been prepared by solid state reaction method. A part of Li + ions in the Li2 MgTiO4 : Mn 4+ are substituted with Na + and K + ions and consequently the intensity of Mn 4+ emission at 678 nm is enhanced by 1.7 and 2.5 times, respectively. In the Mn 4+ /Cr 3+ co-doped (Li0.95 K0.05 )2 MgTi0.999 O4, both emission of Cr 3+ at 726 nm and emission of Mn 4+ at 678 nm of Mn 4+ are observed. It is interesting to find that the intensity ratio of 726–678 nm emissions in the Mn 4+ /Cr 3+ phosphor continually increases with excitation wavelength increasing from 290 nm to 455 nm, which means that the intensity ratio in turn can be used to identify the excitation light wavelength. This refers a possible approach to design novel compact light-wavelength detector or spectrometer based on the phosphor. The mechanism of Na + or K + substitution induced luminescence enhancement in the Mn 4+ phosphor and the competition between the Cr 3+ and Mn 4+ emissions in the Mn 4+ /Cr 3+ co-doped has been discussed.