Efficient Nanosecond Photoluminescence from Infrared PbS Quantum Dots Coupled to Plasmonic Nanoantennas

Abstract

Infrared (IR) light sources with high modulation rates are critical components for on-chip optical communications. Lead-based colloidal quantum dots are promising nonepitaxial materials for use in IR light-emitting diodes, but their slow photoluminescence lifetime is a serious limitation. Here we demonstrate coupling of PbS quantum dots to colloidal plasmonic nanoantennas based on film-coupled metal nanocubes, resulting in a dramatic 1300-fold reduction in the emission lifetime from the microsecond to the nanosecond regime. This lifetime reduction is primarily due to a 1100-fold increase in the radiative decay rate owing to the high quantum yield (65%) of the antenna. The short emission lifetime is accompanied by high antenna quantum efficiency and directionality. This nonepitaxial platform points toward GHz frequency, electrically modulated, telecommunication wavelength light-emitting diodes and single-photon sources.