Quasi 2D Colloidal CdSe Platelets with Thicknesses Controlled at the Atomic Level

Well documented procedures to grow zero-dimensional systems, dots, and one-dimensional systems, wires and tubes, as colloidal particles in solution have been reported. In contrast, there are no methods of preparation that yield optically active two-dimensional soluble particles. Yet, ultrathin films (quantum wells) of II−VI and III−V semiconductors epitaxially grown on substrates by molecular beam epitaxy for example have proven extremely useful for both fundamental studies and a wealth of applications in optoelectronics. We show that II−VI cadmium selenide platelets, with thicknesses tuned at the atomic level, can be synthesized in solution. We describe the method for the preparation of these new colloidal…