Abstract: Engineering band structure and heterointerfaces has been and continues to be critical for advances in electronics, optoelectronics, photovoltaics, and displays among many high-tech applications. Achieving atomic precision through widely accessible and cost-effective means would allow rapid advances in these critical areas. The evolution of colloidal semiconductor nanocrystals from single-composition, “spherical” particles to complex heterostructures of diverse shapes provides many opportunities for precision band structure engineering through scalable solution synthesis. With anisotropic shapes that can be exploited for assembly, charge carrier manipulation and optical anisotropy, etc., incorporating heterojunctions and other functional interfaces into colloidal nanorod heterostructures represents an especially promising direction.
In this talk, general challenges to the synthesis of complex-yet well-defined colloidal nanorod heterostructures will first be discussed. Approaches such as spatially selective solution epitaxy, catalytic growth, cation exchange and combinations thereof can be exploited to achieve unique heterostructures with useful properties. Examples of colloidal nanorod heterostructures of II-VI as well as I-III-VI semiconductors will be discussed. In addition, light-emitting diodes (LEDs) incorporating these materials are shown to not only radically improve existing function but also impart new capabilities without adding complexity in manufacturing.
Bio: Moonsub Shim is a professor in the Materials Science and Engineering department at University of Illinois, Urbana-Champaign. He received his B.S. degree in chemistry from the University of California at Berkeley and his M.S. and Ph.D. degrees in chemistry from the University of Chicago.