Species-related luminescence-structure relationships in europium-exchanged mesoporous material

Europium exchanged into a mesoporous material (Zeotile-1) was extensively characterized with respect to the Si/Al ratio and surface silylation by using time-resolved emission spectroscopy. Qualitative as well as quantitative details of the europium species-related luminescence-structure relationships were obtained and discussed such as the decay associated spectra, local distortion and structure of the bonding environment, crystal-field strength, radiative relaxation rates, and the quantum efficiency. Thus, two europium species were found in the parent as well as in the silylated materials: one species located on the internal surface and the second inside the 2–2.5 nm pores. The species located on the internal surface is characterized by photoluminescence decay times of 105 μs<τ<125 μs, an asymmetry value R of 0.6