Plasmonic Effects on Photobrightening in Cadmium-Selenide Quantum Dots

When quantum dots are exposed to certain wavelengths of light, they photoluminesce. The intensity of this photoluminescence can increase over time, a phenomenon known as photobrightening. The maximum value of the photoluminescence, as well as the rate of photobrightening, are related to the intensity of the excitation light. Metallic nanostructures can enhance this photoluminescence via plasmonic effects. Here, cadmium-selenide quantum dots have been combined with various gold nanostructures, including nanospheres, nanorods, and other structures, to study the enhancement of the rate of photobrightening. Dark-field spectroscopy has been used to determine the wavelengths with which the nanostructures will most readily interact, and photoluminescence has been utilized to find the actual rate of photobrightening. This research shows the relationship between structure and photobrightening rate for various structure shapes, sizes, and concentrations of quantum dots.