Page 57 - PR 2014 2016 10 Materials and Nanotechnology

Materials and Nanotechnology | Progress Report 333

UNDER SUN LIGHT UNDER EXCITATION AT 366 NM

Figure 67. PMMA Films doped with Eu(tta)3 (2-picNO)2 (upper) and Emission spectra of the complex under various excitation (down-left) and
CIE diagram of the 3 differing methyl group in the ligand.

Persistent luminescence materials: the literature, the BaAl O (:Eu ,TR ) materials
2+
3+
2
4
Thermoluminescence and synchrotron are prepared via a solid state route, usually
radiation studies on the persistent by heating BaCO with Al O (or their precur-
3
3
2
luminescent materials sors) at elevated temperatures. However, low
temperature routes as combustion and sol-gel
Since 1995, the research on persistent lumi- syntheses are not uncommon. In the actual
nescence materials has increased substantially research BaAl O materials were prepared: Eu ,
2+
2 4
.This is due to the progress in the properties of TR through the ceramic methods and combus-
3+
these materials: they can emit nowadays in vis- tion, and CdSiO : TR (TR : Y, La, Ce, Pr, Nd, Sm,
3+
3
ible for many, up to 24+ hours, after ceasing the Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) , by ceramic
irradiation. Because of the long emitting time, method, showing persistent luminescence
these phosphors can be exploited commer- property. As usual, the combustion synthesis
cially in emergency signs, road signalization, produces crystals with smaller size, evidently
wall painting, watches, micro defect sensing, due to higher local temperature during the
optoelectronics for image storage and detec- spontaneous explosion. Since the thermolu-
tors of high energy radiation. According to minescence analyses suggested the presence