Achieving Exciton Delocalization in Quantum Dot Aggregates Using Organic Linker Molecules

The design of new complex structures containing semiconductor quantum dots offers a means to create a variety of new meso-solids and molecules. The control of the coupling properties between the dots, accompanied by the energetic tunability of the dots themselves, paves the way toward the application and use of novel quantum properties. Here we present our approach to alteration of interdot coupling using organic linking molecules in a system of covalently bonded, aggregated quantum dots. We used ultrafast transient absorption measurements to identify marks of exciton delocalization over nearest neighbors to some extent. In linking molecules incorporating a benzene ring, the delocalized electron cloud displayed a profound influence over the interdot effects, leading the way to easy coupling control in quantum-based devices, under ambient conditions.