Tunable coupling between exciton and surface plasmon in liquid crystal devices consisting of Au nanoparticles and CdSe quantum dots

We report controllable coupling between exciton and localized surface plasmon in a liquid crystal device consisting of gold nanoparticles and CdSe quantum dots. Through an external electric voltage, the emission wavelength of quantum dots can be manipulated. The underlying mechanism is based on the fact that by changing the dielectric index of liquid crystal with an external bias, the surface plasmon frequency of metal nanoparticles can be adjusted. It is therefore possible to control the energy difference between exciton and surface plasmon resonance, and hence to change their coupling strength. Our strategy may open up a possible route for the development of smart optoelectronic devices with tunable emission color. (C) 2011 American Institute of Physics. [doi:10.1063/1.3606539]