Improved stability of organic-inorganic composite emitting film with sol-gel glass encapsulated Eu-complex

A high-stability organic-inorganic composite emitting film has been realized via a sol-gel process using an optimized silane alkoxide and Eu-complex. We found that the long-term and thermal stabilities were improved by using a combined starting solution of phenyltrimethoxysilane and tetrametoxysilane as encapsulating agent. The resulting emitting film exhibited sharp red-luminescence under ultraviolet (UV) excitation and a high transparency in the visible wavelength region. In addition, no decrease in photoluminescence (PL) quantum yield was observed after thermal treatment up to 180 °C, and the reduction in PL intensity during UV irradiation was suppressed by encapsulating the Eu-complex within the sol-gel derived silica glass.