Plasmonic Nanocavities and Chiral Plasmonic Nanoparticles

Jianfang Wang

Department of Physics, The Chinese University of Hong Kong,

I will present our recent works on plasmonic nanocavities and chiral plasmonic nanoparticles. We have synthesized circular Au nanodisks with excellent size control and fabricated plasmonic Au nanodisk-on-mirror (NDoM) cavities. NDoM cavities exhibit well-controlled anapole and magnetic plasmon modes. Two-dimensional (2D) transition metal dichalcogenide (TMDC) monolayers are successfully sandwiched within NDoM cavities. NDoM cavities have been found to be able to enhance the emissions of bright excitons, switch on dark excitons, and enhance the coherence of valley excitons. We have also developed recipes for the synthesis of chiral Au nanoparticles in the presence of small peptide enantiomers, including chiral Au nanocubes, nanotriskelions, and nanorods. The scattering dissymmetry factors of these chiral nanoparticles can reach +0.57 and −0.49 at 650 nm, respectively. Efficient circularly polarized (CP) organic light-emitting diodes (OLEDs) are further fabricated through the assembly of chiral plasmonic Au nanoparticles and supramolecular aggregates. The emissions of the OLEDs are dominated by either chiral excitons or chiral plasmons, dependning on the type of chiral plasmonic nanoparticle. The CP-OLED showing a high external quantum efficiency of 2.5% and a large dis-symmetry factor of 0.31 is achieved, as a result of multiscale chirality transfer, plasmonic enhancement, and the suppression of the overshoot effect.