Cascading plasmonic and nonradiative energy transfer interactions by plasmon-coupling only donor or only acceptor quantum dots of the energy transfer pairs

Here we present the first proposition and demonstration of cascaded plasmonic and nonradiative energy transfer interactions that are controlled by selectively plasmon-coupling either only donor nanocrystals (NCs), also known as semiconductor quantum dots, or only acceptor NCs of the energy transfer pairs. This scheme uniquely allows for the ability to spatially control plasmon-exciton interactions to take place either at the "start" site (donors) or "finish" site (acceptors) of the energy transfer. We also comparatively study and analyze consequent modifications of NC emission kinetics in response to both cases of plasmon-coupling to only the donor NCs and to only the acceptor NCs through steady-state and time-resolved photoluminescence measurements, along with their lifetime and rate calculations. Also, donor (D) and acceptor (A) NCs made of CdTe are carefully synthesized in different sizes to tune the spectral overlap between donor emission and acceptor absorption as well as to match the plasmon resonance of metal nanoparticles (MNPs).