A polymer solution process for synthesis of (Y,Gd) 3Al 5O 12:Ce phosphor particles

Abstract

Cerium-doped yttrium-gadolinium aluminum garnet, (Y,Gd) 3Al 5O 12:Ce, shortened here to (Y,Gd)AG:Ce, was systematically prepared by a polymer complex method, using high molecular weight polyethylene glycol (PEG). Without PEG, only large flakes several micrometers in size containing nearly pure (Y,Gd)AlO 3 were obtained. Adding PEG dramatically reduced the particle size. However, the (Y,Gd)AG phase was not obtained by merely adding PEG. Instead, mainly (Y,Gd) 2O 3 and small amount of Ce 2O 3 were obtained. Simultaneous use of PEG and a flux (simple salt) such as BF 2 resulted in the formation of small YAG particles. The presence of the (Y,Gd)AG phase results in intense yellow–green luminescence. By selecting various heating routes, the fractions of cubic and hexagonal phases were controlled. It was found that the luminescence intensity is proportional to the fraction of cubic phase, and is probably independent of the hexagonal phase.