Composites of BaAl2O4:Eu2+,Dy3+/organic dye encapsulated in mesoporous silica as multicolor long persistent phosphors based on radiative energy transfer

Abstract

A multicolor BaAl₂O₄:Eu²⁺,Dy³⁺/dye encapsulated in mesoporous SiO₂ composite long persistent phosphor is developed based on a radiative energy transfer process. Multicolor long persistence luminescence is achieved through radiative energy transfer from BaAl₂O₄:Eu²⁺,Dy³⁺ to rhodamine 6G or rhodamine B dye encapsulated in mesoporous silica nanoparticles. BaAl₂O₄:Eu²⁺,Dy³⁺ (BAO) is a cyan-emitting long persistent phosphor with high brightness and a long afterglow time. For color tuning, rhodamine 6G dye encapsulated in mesoporous silica (MSNP-Rh6G) or rhodamine B dye encapsulated in mesoporous silica (MSNP-RhB) nanoparticles are mixed with BAO phosphor in different weight ratios to afford BAO/MSNP-Rh6G and BAO/MSNP-RhB composite phosphors. BAO/MSNP-Rh6G shows a long persistent emission with colors varying from cyan to yellow, with similar color tuning observed for BAO/MSNP-RhB. A possible afterglow mechanism is described. The multicolor long persistent phosphors are potentially applicable in displays, bio-imaging, and luminous paints.