The charge states' conversion of the activator ions in CaF2:Eu nanophosphors

作者：Antonyak O T^*; Khapko Z A; Chylii M O

来源：Radiation Effects and Defects in Solids-Incorporating Plasma Science and Plasma Technology, 2017, 172(5-6): 456-468.

DOI：10.1080/10420150.2017.1336763

• Eu3+ -> Eu2+ conversion
• CaF2:Eu nanoparticles
• thermal annealing
• X-ray-excited luminescence spectra
• thermally stimulated luminescence

According to stationary X-ray-excited luminescence spectra and thermally stimulated luminescence spectra of CaF2: Eu nanophosphors, it was found that Eu3+ -> Eu2+ conversion can occur during thermal annealing of fine-grained (d = 25 nm) nanoparticles in the 200-800 degrees C range, which is accompanied by an increase in their size within 40-189 nm. An important role of the exciton mechanism of Eu2+ luminescence excitation was revealed according to the temperature dependence of X-ray-excited luminescence spectra of CaF2: Eu nanoparticles of 114nm size. The maximum of the X-rayexcited luminescence light output of CaF2: Eu nanophosphors in the Eu2+ ions' emission band was traced out at 400-500 degrees C annealing temperature and at the size of nanoparticles of 114-180 nm. The subsequent growth of the annealing temperatures, particularly in the 800-1000 degrees C range, causes the reduction of X-ray-excited luminescence light output because of the increment of lattice defects' concentration due to a sharp increase in the size of nanoparticles and their agglomeration.

• 出版日期2017