Nanocrystals for Solar

In Alex Chang’s lab in the School of Chemical, Biological and Environmental Engineering, researchers arrange atoms in precise patterns to create materials with novel electrical and heat-transfer properties. Chang and his colleagues use electron microscopy to visualize and analyze structures that are often only a few atoms thick.

“The EM facility is very important for our work,” says Chang. “It allows us to look at the structures in high resolution.”

These flower-like particles are among a variety of curious shapes created by zinc-oxide nanoparticles. Others appear as needles or spheres. After mixing a solution in a continuous-flow microreactor (a device in which chemical reactions occur in tiny channels), Chang and his team deposit particles as a film on a heated surface and then slowly cool the film. They have used this relatively simple technique to make transistors as well as materials with high heat-transfer characteristics. Motor and window manufacturers are among the companies that have expressed interest in Chang’s work.