Synthesis of phosphor photonic crystal by self-assembly of spherical phosphor and control of its photoluminescence properties

Abstract

With continuous growth of display industry, researchers have made great efforts to improve the efficiency of display devices. Because the improved efficiency of display devices results in reduction of energy consumption, it is very important and means a lot. The efficiency of display devices is strongly depended on the properties of luminescence materials used, because luminescence materials play an important role of emitting visible lights in each device. As luminescence materials with the higher luminescence efficiency were used, the more efficient display devices can be expected. Therefore, many researchers have studied to improve the efficiency of luminescence materials and to search for new luminescence materials with high efficiency. In this study, 3 dimensional (3D) colloidal photonic crystals (PCs) were used and studied to improve the efficiency. At first, the effects of the 3D colloidal PCs and their stopbands on the light extraction efficiency of luminescent films were investigated. In addition, the phosphor PCs were fabricated by self-assembly of the monodisperse phosphor spheres, and their advantages and utilization ways were investigated. Finally, the effects of the crystallite/particle sizes on the luminescence properties of inorganic phosphors were investigated by using the monodisperse phosphor spheres. In chapter 3, in order to verify the distinct advantages of the colloidal 3D PCs on the extraction efficiency, an organic-inorganic hybrid transparent luminescence material, the $Ormosil:Eu(dbm)_{3}phen phosphor$, was experimented. The luminescence properties of the plane film prepared by spin-coating of the phosphor on a slide glass were compared with those of the infiltrated film prepared by infiltration of the phosphor into the 3D colloidal PC. The photoluminescence (PL) intensity of the infiltrated film was about 13 times higher than that of the plane film. Three major terms, which are the mass term, the scattering term, and the crystallini...