Staggering benefits from nanoparticles.

• Position: Solar Energy

Scientists are describing a revolutionary new way to use sunlight to produce steam and other vapors without heating an entire container of fluid to the boiling point. The advance has potential applications--especially in the poverty-stricken areas of the developing world--that include inexpensive, compact devices for purification of drinking water, sterilization of medical instruments, and sanitizing sewage.

"This research opens up a revolutionary new application of nanoparticles in solar energy," notes Paul Weiss, editor-in-chief of ACS Nano. "The authors show that sunlight can be used to create steam with virtually no wasteful heating of the surrounding liquid. The potential societal benefits are staggering. They include more energy-efficient distillation of alcohol, a new and highly practical strategy for desalination and water purification, and compact solar-driven sources of steam for sterilization and sanitation in resource-poor locations."

Naomi Halas and Peter Nordlander, chair and professor, respectively, of the Department of Electrical and Chemical Engineering at Rice University, Houston, Texas, note in the report that metallic nanoparticles (so small that 1,000 would fit across the width of a human hair) absorb large amounts of light, resulting in a dramatic rise in their temperature. That ability to generate heat has fostered interest among scientists in using nanoparticles in a range of applications. These include photothermal treatment of certain forms of cancer, laser-induced drug release, and nanoparticle-enhanced bioimaging.

Scientists in the past also explored the use of nanoparticles in solar energy applications. However, that research focused mainly on using nanoparticles to improve the ability of fluids to conduct heat. Until now, scientists had not reported on the use of nanoparticles mixed into...