Surface-treatment of Alkaline Earth Sulfides Based Phosphor

A series of alkaline earth sulfides based phosphors Ca0.8Sr0.2S∶Eu2 , Tm3 were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH4HF2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.