Through a process known as thermionic conversion, heat energy — such as light from the sun or heat from burned fossil fuels — can be converted into electricity with very high efficiency.
Because of its promise, researchers have been trying for more than half a century to develop a practical thermionic generator, with little luck. That luck may soon change, thanks to a new design — dubbed a thermoelectronic generator — described in AIP Publishing’s Journal of Renewable and Sustainable Energy (JRSE).
See: http://dx.doi.org/10.1063/1.4817730.
Source http://www.aip.org/
full article:
http://www.activistpost.com/2013/12/new-generator-converts-heat-and-solar.html