Enhancement of fluorescence from single molecules of perylene diimide (PDI) on tantalum pentoxide (Ta2O5) two-dimensional photonic crystal (PC) slabs with low background emission was observed using a single-molecule fluorescence spectroscopy technique. The fluorescence intensity of the single molecules on the PC was more than 3 times higher than that of the molecules without the PC. The performance of the PC slabs with a 100 objective lens was evaluated by steady-state and time-resolved ensemble fluorescence measurements. The mechanismof the enhancement was attributed to coupling of an excitation laser and fluorescence to the PCs' modes. The present results yield new insights into a highly sensitive investigation of single molecules and regulation of fluorescence emission from them via the effect of PCs.

doi:10.1021/jz2006989