High efficiency luminescent polystrene beads with a novel europium phenanthrene diketonate

Abstract

Fluorescent or luminescent polymer particles (beads) have become an important tool in bioanalytical and other applications, the size regime of interest ranging from some ten to a few hundred nanometers. Bead-imbedded rare earth complexes are of particular interest, which is owed to their narrow line emissions, large separation between excitation and emissions (apparent Stokes shifts) and extrordinarily longs decay times of the emission. The latter is advantageous for the discrimination against undesired background (e.g. autofluorescence) via time gated analysis; high quantum yields and high absorptions of the incident radiation at the same time are dominant optical criteria. We here describe and characterize a new Eu3+ diketonate comprising tris(3-phenanthryl-3,3,3-trifluoroacetone)Eu(III)-di(tri-n-octyl phosphine oxide), Eu(pta)3(TOPO)2, in polystyrene with high quantum efficiencies (up to 90%) and long decay times (up to 680 μs).