Metal-enhanced phosphorescence (MEP)

We report the first observation of metal-enhanced phosphorescence (MEP) at low temperature. Silver island films (SiFs) in close proximity to Rose Bengal, significantly enhance the phosphorescence emission intensity. The enhanced phosphorescence intensity is ≈5-fold brighter from SiFs as compared to a glass control sample at 77 K. In addition, enhanced fluorescence emission and spectral narrowing were observed at low temperatures. Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance both fluorescence and phosphorescence yields. This finding suggests that MEP can be used to promote triplet-based assays, such as those used in photodynamic therapy.