An attempt to enhance the afterglow luminescence of NIR light emitting long persistent phosphor Zn3Ga2Ge2O10:Cr3+ by Pr3+ co-doping.

The long persistent phosphors Zn 3 Ga (2-x-y) Cr x Pr y Ge 2 O 10 were developed by solid state reaction method. Developed phosphor shows long after glow decay and emission characteristics. NIR light emission through the phosphor after UV light irradiationis captured by night vision monocular and it shows the long after glow luminescence of more than 24 h. [Display omitted] • A series of long persistent Zn 3 Ga (2-x-y) Cr x Pr y Ge 2 O 10 phosphors were developed by solid state reaction method. • Structural, optical and photo and thermo luminescence properties are discussed in details. • A significant enhancement in afterglow luminescence has been occurred after incorporation of Pr3+ ions. In this study we have focused on the improvement of luminescence intensity and the long afterglow luminescence of Cr3+ doped Zn 3 Ga 2 Ge 2 O 10 long persistent phosphor by adding an appropriate amount of Pr3+ ions in proportion with Ga concentration. We have successfully developed a series of long persistent Zn 3 Ga (2-x-y) Cr x Pr y Ge 2 O 10 (where x = 0, 0.04 and y = 0, 0.01, 0.02, 0.03, 0.04) phosphors by high temperature solid state reaction method. The structural properties of the developed phosphors were characterized by X-ray diffraction method. The diffuse reflectance spectra were recorded at room temperature and it shows three strong absorbance bands at the wavelength of 256, 412 and 570 nm due to the transitions of 4A 2g →4T 1g (4P), 4A 2g →4T 1g (4F) and 4A 2g →4T 2g (4F) of Cr+3 ions which are also confirmed from the photoluminescence (PL) excitation spectra. PL emission analysis revealed that developed phosphors have a strong narrow luminescence around 698 nm and significantly enhanced with the Pr3+ content upto its optimum value (0.02). Afterglow NIR light emission from the developed phosphors was captured by night vision monocular and it is found that the phosphors have long persistent luminescence for more than 24 h. Thermoluminescence (TL) measurement was also carried out for better understanding the kinetic mechanism and luminescence process in these materials. This will enable to calculate the trapping parameters associated with prominent glow peaks. [ABSTRACT FROM AUTHOR]