By trapping organic molecules between a gold surface and the ultrafine gold tip of a scanning tunneling microscope, researchers have shown that the molecules could be used to generate electricity. Credit: Arun Majumdar

Materials that convert heat directly into electricity have been useful for some niche applications, like powering deep-space probes. But they've been too expensive and inefficient for their potential killer app: harvesting immense amounts of energy from the waste heat generated by power plants and cars. Now researchers at the University of California, Berkeley, have shown that a cheap organic material can make electricity from heat, potentially opening the way to affordable "thermo­electrics."

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