The 2011 Von Hippel Award, the Material Research Society’s highest honor, will be presented to A. Paul Alivisatos, director of the Lawrence Berkeley National Laboratory and Larry and Diane Bock Professor of Nanotechnology, University of California–Berkeley. Alivisatos is being recognized for “the development of the fundamental scientific basis for growing and utilizing defect-free colloidal semiconductor nanoparticles, providing the basis for biological imaging, solid-state lighting, and the capture and conversion of solar energy to electricity.” Alivisatos will accept the honor during the awards ceremony at the 2011 MRS Fall Meeting in Boston.
One of the most important building blocks of nanoscience is the colloidal nanocrystal. High-quality, defect-free colloidal inorganic nanoparticles of controlled size and shape are now made routinely by thousands of research groups around the world, and their size-dependent properties are widely studied. A few key foundational studies by Alivisatos and co-workers provided an understanding of the underlying principles and scaling laws needed for this class of material to be developed.
Alivisatos has mapped out the size-dependent melting of quantum dot semiconductor materials, showing how it is possible to anneal out defects, and to eject impurities from a growing colloidal nanoparticle formed at just a few hundred degrees C, well below the temperatures needed to form high-quality epitaxial two-dimensional films. Alivisatos also showed that size control depends upon careful separation of nucleation and growth, as well as the time scales involved, and upon the concept of “size distribution focusing,” in which the distribution of nanoparticle sizes is narrowed when small particles grow faster than large ones. Proof of the high quality of nanocrystals is gleaned from studies of optical properties, as well as from studies of the structural transformations of nanoparticles under high pressure, demonstrating the absence of defects. The synthesis of high-quality colloidal nanocrystals rests upon key work by Alivisatos, and is an essential component of the development of colloidal quantum dots and other nanocrystals.
Colloidal quantum dots are the size of a protein molecule, and when appropriately functionalized, can be introduced inside cells and tissues as biological labels. They are used currently in fluorescent imaging in biology because they do not bleach and they yield a family of solid-state materials with a wide range of emission colors and superior luminescence characteristics, yet they can be processed in solution to make them biocompatible. Alivisatos founded Quantum Dot Corporation, which makes colloidal quantum dots commercially available to researchers.
In 1994, Alivisatos and co-workers demonstrated the first light-emitting diodes made with colloidal quantum dots, the basis of some early quantum dot solid-state lighting products with low manufacturing cost, high color purity, and low energy consumption. Similarly, colloidal quantum dots are under investigation in a range of solar cell designs developed by Alivisatos and co-workers— the low cost and high volume processing of these quantum dots may enable new types of solar photovoltaic and solar fuel generators.
In the last decade, Alivisatos has demonstrated the emergence of “artificial molecules,” where small numbers of colloidal nanoparticles are joined together into specific “molecular” arrangements with controlled symmetry and connectivity. These new “molecular” systems have opened a new area of materials for discovery and innovation. An important breakthrough by Alivisatos in this area has been the demonstration of the “plasmon ruler,” which, for example, can measure the distance between two Au nanocrystals joined by DNA or peptides to measure dynamical distance changes in biological systems.
Another important area Alivisatos has pioneered is the study of chemical transformations of colloidal nanocrystals. He has also demonstrated methods for making branched nanocrystals, discovered the nanoscale Kirkendall effect, a general approach for making hollow nanoparticles, and has developed concepts of ion exchange in nanocrystals as a means of separately controlling the composition, size, and shape of a colloidal nanocrystal system.
Alivisatos received a Bachelor’s degree from the University of Chicago in 1981, and a PhD degree in physical chemistry from the University of California–Berkeley in 1986. He was a postdoctoral fellow at AT&T Bell Labs (1986–1988). He joined the University of California–Berkeley as a faculty member in 1988. He became director of the Lawrence Berkeley National Laboratory in 2009.
Alivisatos has over 220 publications and over 15 patents. He is the scientific founder of Quantum Dot Corp.; Nanosys, Inc.; and Solexant, Inc. and founding editor of Nano Letters.
His honors include the Alfred P. Sloan Foundation Fellowship; the ACS Exxon Solid State Chemistry Fellowship; the Coblentz Award; the Wilson Prize at Harvard; the Materials Research Society Outstanding Young Investigator Award; the ACS Award in Colloid and Surface Chemistry; the Rank Prize; the Eni Italgas Prize for Energy and Environment; the Ernest Orlando Lawrence Award; and the Kavli Distinguished Lectureship in Nanoscience, MRS. He is a fellow of both the American Physical Society and the American Association for the Advancement of Science. In 2004, he was elected into the National Academy of Sciences and the American Academy of Arts and Sciences.
The MRS Von Hippel Award includes a $10,000 cash prize, honorary membership in MRS, and a unique trophy—a mounted ruby laser crystal, symbolizing the many faceted nature of materials research. The award recognizes those qualities most prized by materials scientists and engineers—brilliance and originality of intellect, combined with vision that transcends the boundaries of conventional disciplines, as exemplified by the life of Arthur von Hippel (http://vonhippel.mrs.org).
