Improved Durability of Eu Chelate Encapsulated by Silica Glass Film Prepared by Sol-Gel Method

Abstract

We demonstrated an improved durability of Eu(HFA)3(TPPO)2 [tris(hexafluoroacetylacetonato)- europium(III) 1,2-phenylenebis(diphenylphosphine oxide)] encapsulated by a sol-gel derived silica glass film. The film was constructed using phenyltrimethoxysilane and diethoxy- dimethylsilane as a starting solution. Unlike cases in which conventional tetramethoxysilane is used, no decrease in internal quantum efficiency was observed at room temperature. We further improved the thermal and long-term stability of Eu(HFA)3(TPPO)2 inside the transparent glass film at elevated annealing temperatures when compared to the Eu(HFA)3(TPPO)2 powder itself: The photoluminescence quantum efficiency of the transparent film was 60% at 160℃ and 32% at 20℃. Properly prepared glass networks protect the Eu chelate from free oxygen and water in the transparent glass film, which is promising for future practical applications.