10.1016/j.jallcom.2015.11.182
Synthesis of lanthanide doped CeF3:Gd3+, Sm3+ nanoparticles, exhibiting altered luminescence after hydrothermal post-treatment
 The syntheses were carried out to produce 0.75 g of the product. NH4F (50% excess) was dissolved in 25 mL of water (solution A). An aqueous solution B was prepared that contained Ln(NO3)3 and CeCl3 which were mixed at the desired molar ratio (0.01 Sm(NO3)3, 0.15 Gd(NO3)3 and 0.84 CeCl3 mol%), and diluted with water to make 100 mL. In the case of the products obtained in the presence of EDTA and citric acid, 0.5 wt.% of the desired polycarboxylic acid was additionally dissolved in solutions A and B. The pH of the systems was adjusted to [?]7, by the use of an aqueous NaOH solution. Solution B was added dropwise to solution A, resulting in the precipitation of the lanthanide doped fluorides (LnF3). The reaction was performed at 343 K, with continuous stirring. Afterward the as-prepared products were divided into two parts. Half of the product was purified by centrifugation and washed several times with water. After this the product was dried overnight in the oven (at 358 K). The rest of the colloidal precipitate was transferred into a Teflon vessel and hydrothermally treated for 2 h, at 453 K/40 bar (microwave autoclave - ERTEC, Magnum II, 600 W). When the reaction was finished, the product obtained under hydrothermal conditions was purified by centrifugation and dried in the oven, as well.
product
0.75 g
g
NH4F
excess
50%
%
water
25 mL
mL
Sm(NO3)3
molar ratio
0.01 Sm(NO3)3, 0.15 Gd(NO3)3 and 0.84 CeCl3 mol%
mol%
systems
pH
7
solution B
diluted
100 mL
mL
polycarboxylic acid
dissolved
0.5 wt.%
wt.%
reaction
performed
343 K
K
product
overnight
358 K
K
rest of the colloidal precipitate
hydrothermally treated
2 h
h
rest of the colloidal precipitate
hydrothermally treated
40 bar
bar
rest of the colloidal precipitate
hydrothermally treated
453 K
K