One-step preparation of pyrene-doped silica particles with tunable emission and their application for ethanol detection

Abstract

In this work, pyrene-doped silica particles were prepared by a modified Stöber method with the assistance of cetyltrimethylammonium bromide (CTAB) micelles. In this one-step approach, incorporation efficiency of the dye into the silica particles could be improved to be as high as 90% in a wide range of pyrene concentration (20⿿200μM) by optimizing the volume ratio of ethanol/water in the reaction solution and thus the distribution of the dye in the solvent and CTAB micelles. Emission color of the particles was tunable readily by changing the concentration of pyrene in the reaction solution. At low pyrene concentration, emission of the silica particles was dominated by the violet emission of pyrene momomer. At high pyrene concentration, emission of the silica particles was dominated by the green color of pyrene excimer. After redispersing the silica particles with green color into the ethanol/water mixture, emission color of the particles was sensitive to the content of ethanol. Emission color of the silica particles evolved from green to blue and then violet with the increased content of ethanol attributed to the promoted release of the doped dye and thus suppressed emission of the excimer.