Metal-Enhanced Excimer (P-type) Fluorescence.

In this letter, we report the first observation of metal-enhanced excimer (P-type) fluorescence from pyrene. Pyrene in close proximity to silver island films (SIFs) shows enhanced pyrene excimer emission with a approximately 2.5-fold higher emission intensity observed from SIFs and 5x10(-3) M pyrene, as compared to a quartz control sample containing no silver nanoparticles. Our findings suggest two complementary methods for the enhancement: i) surface plasmons can radiate coupled monomer and excimer fluorescence efficiently, and ii) enhanced absorption (enhanced electric field) further facilitates enhanced emission. This observation is helpful in our laboratory's continued goal to develop a unified plasmon-luminophore description.