Synthesis of ternary compound sulfide nanoparticles

Conventional phosphor materials are doped ternary or quaternary compounds; hence it would be difficult to prepare those nanoparticles by build up methods. Ba₂ZnS₃:Mn, SrGa₂S₄:Eu, and BaAl₂S₄:Eu nanoparticles were prepared by a break down method, namely ball-milling method. Transmission electron microscopy (TEM), and TEM-energy-dispersive X-ray spectroscopy (EDX) measurements showed several-nanometer-size stoichiometric and dispersed nanoparticles were achieved. The annealing was performed after the milling for those particles to cure the mechanical damages. The annealing in a vacuum at around the calcination temperature of starting materials showed the cured photoluminescence (PL). ZnO-coating was performed and the uniform coating layer of the thickness about 10nm was formed on the phosphor nanoparticles. The ZnO-coated nanoparticles exhibited an improved stability in PL.