“…The La 2 Hf 2 O 7 :xmol%Pr 3+ NPs (x = 0.0, 0.1, 0.2, 0.3, 0.5, and 1.0) were prepared using a two-step molten salt process, which generates nanoparticles at a relatively low temperature as reported by our group and some other groups, for example in the synthesis of YAG:Ce and LuAG:Ce. 19,21,[29][30][31] First, a single-source precursor was prepared by measuring (5 À x) mmol of La(NO 3 ) 3 Á6H 2 O and 5 mmol of HfOCl 2 Á8H 2 O and x mmol of Pr(NO 3 ) 3 Á6H 2 O, where x is equal to the mol% with respect to the La 3+ sites. The materials were dissolved in 200 mL of 18.2 mO Millipore water while simultaneously stirred with a magnetic stirring rod.…”