Giant photoluminescence enhancement in SiC nanocrystals by resonant semiconductor exciton-metal surface plasmon coupling.

We report giant fluorescence enhancement in SiC nanocrystals (NCs) embedded in a sodium dodecyl sulfonate dielectric medium by proximately contacted Ag nanoparticles. The enhancement in integrated fluorescence intensity reaches an astonishing 176-fold under 360 nm excitation (53.3-fold enhancement in emission maximum intensity). Finite-element simulation indicates that the strong resonant coupling between the excited SiC NCs and localized surface plasmons of the Ag nanoparticles plays a dominant role in determining fluorescence enhancement. In contrast, the absorption enhancement caused by light concentration around the Ag nanoparticles makes only a slight contribution to the overall enhancement. Our result opens the possibility of applications of these highly enhanced fluorescent SiC NCs in diverse areas such as sensing, optoelectronics and life sciences.