Wavelength shifting systems based on flavonols and their metal complexes encapsulated by post-doping in porous SiO2 xerogel matrices

SiO2 xerogels with very low organic and silanol content have been doped with flavonols and flavonol–metal complexes through a post-doping encapsulation procedure.With a final aim of developing wavelength shifters, this work has shown that 3-hydroxyflavone (3HF) and Al(3HF)2+-doped xerogels have interesting luminescent properties. Moreover, spectroscopic characterization of these two doped xerogels shows that the encapsulation procedure does not significantly alter the emission properties of the dopant species. For 3HF-doped xerogels, emission studies and Raman analyses suggest that the encapsulated dye is surrounded by an apolar but inorganic nanoenvironment.This study demonstrates the possibility of obtaining organic fluorophor- and metal-complex fluorophor-doped xerogels with good optical properties fabricated by a simple soaking and drying post-doping procedure.