Efficient Red Emission from Europium Chelate-Silicone Host-Guest Hybrids

Abstract

Due to their ease of fabrication, chemical stability and optical transparency polydimethylsiloxanederived silicones ([O-Si(CH3)2]∞) are excellent matrices to enable optical functions. We here report on the luminescence of silicone hybrids with red-emitting europium diketonate complexes, which have not been described previously in this matrix. The problem of too low solubility of the pure complexes has been resolved by co-coordination with trioctylphosphine oxide (TOPO), which permits complex concentrations of up to 5×10−3 mol L−1, at the same time maintaining complete transparency. Quantum efficiencies in excess of 60% could thus be obtained for benzoyltrifluoroacetonates, and near 50% for thenoyltrifluoroacetonates. These high efficiencies have been confirmed by room-temperature life time measurements, which displayed straight single-exponential decay behavior for both complexes independent of their concentration in the silicone.