Metal-enhanced e-type fluorescence.

In this letter, we report metal-enhanced e-type fluorescence. Eosin in close proximity to silver island films (SiFs) shows enhanced e-type fluorescence with an approximately two-fold higher intensity observed from SiFs, as compared to a control sample. Our findings suggest two complementary mechanisms for the enhancement: surface plasmons can radiate e-type delayed fluorescence efficiently and enhanced absorption also facilitates enhanced emission from both S(1) and T(1) states. This observation is helpful in our understanding not only for studying the interactions between plasmons and fluorophores but also for our laboratories continued efforts to develop a unified plasmon-lumophore description.