Photoluminescence Investigation of the InP/ZnS Quantum Dots and Their Coupling with the Au Nanorods

The photoluminescence spectra of the InP/ZnS quantum dots (QDs) and the composite structure of the InP/ZnS QDs coupled with Au nanorods are investigated in this paper. In the luminescence spectra of the two samples, the recombination of the bright-dark doublet exciton states and an upper bright exciton state are observed at the temperature 11-130K. The temperature dependence of the main emission peaks of the InP/ZnS QDs and the composite structure can be expressed by the Varshni expression in the temperature range of 11-300K. The coupling between the QDs and the surface plasmon resonance (SPR) states has a great effect on the exciton recombination and the defect recombination. Because of the coupling, the variation range of the main emission peak of the composite structure is about 28meV more than the pure QDs with the temperature from 11K to 300K. The red shift of the defect emission with increasing temperature is coincident with the red shift of the SPR energy with increasing temperature. The experimental results confirm that the energy transfer from the SPR states is the main source of the defect emission.