Building with artificial atoms:

The design of multifunctional nanomaterials and devices through nanocrystal self-assembly.

Christopher B. Murray^(1,2)

University of Pennsylvania, Departments of (1) Chemistry and (2) Materials Science 

Abstract:  The synthesis of monodisperse colloidal nanocrystals (NCs) with controlled composition, size and shape provides ideal building blocks for the assembly of new thin films and devices. These monodisperse colloidal NCs can be thought of as "artificial atoms" with tunable electronic, optical, magnetic properties that are allowing the development of a new periodic table for design at the Mesoscale.  In this talk I will briefly outline the current state of the art in synthesis, purification, and integration of single phase NCs and core-shell (heterostructures) NCs emphasizing the design of semiconductor building blocks with tunable shapes (spheres, roads, cubes, discs, octahedra etc...  I will then share how these tailored NCs can be directed to assemble into single-component, binary, ternary NC superlattices providing a scalable route to the production of multi-functional thin films. The modular assembly of these NCs allows the desirable features of the underlying quantum phenomena to be retained and enhanced even as the interactions between the NCs allow new delocalized properties to emerge.   Synergies in electronic, optical coupling between NCs will be emphasized as we pushing toward the realization of artificial solids with a new 3D and structure and high mobilities (>30 cm2V-1S-1) device integration. I will share specific case studies in thin film transistors, thermo-electric materials and solution-processable photovoltaic devices build with these strongly coupled nanocrystal solids highlighting the recent developments in wafer scale NC superlattice deposition and patterning may provide a path to scalable fabrication.   In a final example of hetero-integration I will present our progress in the co-assembly of plasmonic resonators together with nanoscale emitters as a route to the scalable self-assembled MetaMaterials with novel linear and non-linear optical properties.  

Bio: Dr. Christopher B. Murray holds the Richard Perry University Professorship in Chemistry and Materials Science at the University of Pennsylvania in Philadelphia, PA, where his research focuses on the preparation, characterization and integration of nanomaterials.  Prior to joining Penn, Chris was a Staff Scientist and Manager in the IBM’s Research Division from 1995 to 2006 where he lead the "Nanoscale Materials & Devices" Department at the T. J. Watson Research Center.  Chris received his BSc. degree with Honors in Chemistry from St. Mary's University in Halifax Nova Scotia Canada (1988) and spent a year as a Rotary International Fellow at the University of Auckland, New Zealand studying Chemistry and Materials Science before pursuing his PhD. in Chemistry at the Massachusetts Institute of Technology.  While at MIT Chris worke dunder the supervision of Prof. Moungi G. Bawendi focusing on the synthesis and characterization of semiconductor quantum dots and quantum dot solids, completing his PhD. in 1995. The American Chemical Society recognized the pioneering contributions in Chris’graduate thesis with the Nobel Laureate Signature Award.  Chris has continues champion the development of materials chemistry  by bringing together colloidal synthesis and nanoscale materials chemistry and with aspects of traditional top-down patterning and processing. He has expanded beyond semiconductors to explore opportunities in nanomagnetics, plasmonics and catalysis. Increasingly his research is focused on the application of nanotechnology and materials design to issues that impact information technology, energy and environmental sustainability and human health.  Chris has authored more than 200 scholarly articles, holds over 25 patents, and has presented over 250 public lectures in the field of nanocrystal synthesis and self-assembly and on the engineering of nanomaterials and nanodevices.  In 2011 he received an Honorary Doctorate from the University of Utrecht, The Netherlands recognizing contribution to the design of nanomaterials for energy sustainability, and in 2012 Chris was recognized as a Fellow of the Materials Research Society. Chris also contributes to the broader scientific community in nanoscience and engineering by serving on numerous advisory boards for national and international scientific centers, journals, conferences and professional organizations.