Fast Energy Transfer in CdSe Quantum Dot Layered Structures: Controlling Coupling with Covalent-Bond Organic Linkers

Quantum dot (QD) solids and arrays hold a great potential for novel applications which are aimed at exploiting quantum properties in room-temperature devices. Careful tailoring of the QD energy levels and coupling between dots could lead to efficient energy-harvesting devices. Here, we used a self-assembly method to create a disordered layered structure of QDs, coupled by covalently bonded organic molecules. Energy transfer rates from small (donor) to large (acceptor) QDs are measured. Best tailoring of the QDs energy levels and the length of the linking molecules results in an energy transfer rate as high as 30 ps^-1. Such rates approach energy transfer rates of the highly efficient photosynthesis complexes and are compatible with a coherent mechanism of energy transfer. These results may pave way for new controllable building blocks for future technologies.