Researchers at the University of California, Los Angeles have created thermoelectric coolers that are only 100 nanometers thick. These coolers are made by sandwiching two different semiconductors between metalized plates. When heat is applied, one side becomes hot and the other remains cool; that temperature difference can be used to generate electricity. But that process can also be run in reverse: When an electrical current is applied to the device, one side becomes hot and the other cold, enabling it to serve as a cooler or refrigerator.
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