Narrow-band tuneable emission of CdSe/ZnS quantum dots by exploiting high-order resonant cavity modes of plasmonic nanorod arrays

Abstract Colloidal semiconductor quantum dots (QDs) enable tuneable emission via the quantum size effect, yet their emission is limited by non-radiative Auger recombination. Although metal nanostructures supporting surface plasmons provide a pathway for emission enhancement, the resulting QD emission typically remains broad. Here, we demonstrate narrow-band tuneable emission of CdSe/ZnS QDs by exploiting high-order resonant cavity modes of plasmonic nanorod arrays. An optimized PMMA spacer between the QDs and the plasmonic nanorod arrays maximizes the emission enhancement. By varying the resonant cavity modes of the plasmonic nanorod arrays, discrete narrow-band emission peaks are obtained at 646, 652, 657, 662, and 670 nm, with linewidths narrowed to 5-6 nm. This approach offers a promising route for high-performance, tuneable light-emitting devices.