Plasmon - Exciton Interaction in Gold - CdTe Nanostructures

Abstract

In this work, conjugation of metal and semiconductor nanoparticles was chemically done and the properties of Au-CdTe hybrid nanostructures were studied using various characterization methods. Intriguing properties were observed due to coupling of excitons in semiconductor nanoparticles and plasmons in metal nanoparticles. When combined into heterostructures, the nanometer-scale vicinity of the two systems leads to interaction between quantum-confined electronic states in semiconductor nanostructures and dielectric-confined electronic states in the metal counterparts. The interaction between individual nanoparticles has been revealed as an enhancement or suppression of emission in case of conjugated gold nanorods and CdTe quantum rods as well as suppression of emission in gold nanostars and CdTe quantum rods heterostructures where enhancement of excitonic absorption was also observed. Enhanced emission comes from electric field amplified by the plasmon resonance, whereas emission suppression is a result of energy transfer from semiconductor to metal nanoparticles. Such exciton-plasmon interactions allow designing of absorption and emission properties, control of nanoscale energy-transfer processes which can have potential applications in the fields of optical sensing, fluorescence based sensors, photovoltaic systems and various other fields.