Localized surface plasmon resonance enhanced photoluminescence of CdSe QDs in PMMA matrix on silver colloids with different shapes

Localized surface plasmon resonance (LSPR) enhanced photoluminescences (PL) from CdSe quantum dots (QDs) on worm-like or quasi-spherical silver colloids have been investigated. The shape of silver colloid film is controlled by annealing temperature (200 °C∼350 °C). Strong PL enhancements of CdSe QDs on both as-grown and annealed silver colloid films are observed. The results show that the PL enhancement factor of CdSe QDs on worm-like silver colloid film reaches as high as 15-fold. Moreover, the enhancement factor is 5 times larger than that obtained from the quasi-spherical silver colloids. The superiority of worm-like silver nanostructure on LSPR enhanced photoluminescence is attributed to its larger size, hot spots and multiple dipole resonance modes coupling, which are induced by aggregation effect.