Colloidal nanocrystals have been watershed materials in nanoscience and nanotechnology research, demonstrating in the early 1980s that small is indeed different. Nanocrystals continue to be very important as model systems for testing fundamental ideas in condensed matter physics and as unique building blocks for designing new nanocomposite materials.

Colloidal nanocrystals are fascinating materials because of their extraordinary flexibility and their remarkable diversity of properties. They are unique hybrid materials consisting of a solid core protected by a soft outer shell of organic molecules. Traditionally, our building blocks have been limited to the known elements, with each element's properties determined by the number of electrons. In contrast, we can adjust the properties of nanocrystals by changing almost trivial properties such as core size or type of capping molecules. In this way, the colloids act like artificial atoms and transcend the periodic table. Such flexibility promises highly-optimized designer materials for applications as diverse as catalysts, sensors, magnetic storage media, solar cells, lasers, medical probes and therapeutics.

My research is aimed at learning three things: (i) new ways of assembling colloidal nanoparticles into complex structures; (ii) how particle interactions affect the structure and physical properties in these unique materials; (iii) if it is possible to synthesize structurally perfect nanocrystals. To answer these questions, I work with nanometer-sized inorganic particles, including gold as a model system. These nanocrystals are protected by a monolayer of organic molecules, such as dodecanethiol for gold, which keeps them from sintering. This research spans many diverse fields, including physical, inorganic, and organic chemistry, hard and soft condensed matter physics, and materials, chemical and mechanical engineering.