320-fold luminescence enhancement of [Ru(dpp)3]Cl2 dispersed on PMMA opal photonic crystals and highly improved oxygen sensing performance

Abstract

Ru complexes ([Ru(dpp)3]Cl2) were spin coated on poly(methyl methacrylate) (PMMA) opal photonic crystals (PhCs), and a ,320-fold luminescence enhancement was observed compared to that on glass, which is the largest luminescence enhancement of dye molecules by the modulation of three-dimensional (3D) PhCs reported until now. The enhancement mechanism was carefully examined and it was shown that the luminescence of [Ru(dpp)3]Cl2 depended on the molecule concentration and temperature. It can be concluded that the suppressed non-radiative relaxation among the molecules and the field enhancement both contribute significantly to the luminescence enhancement. The PMMA PhC/Ru complex composites were then tested for their intracellular oxygen sensing and cell imaging properties; these composites effectively improved the limit of detection (LOD) and the brightness of the cell images.