Thermionics, Thermoelectrics, and Nanotechnology: New Possibilities for Old Ideas

The term solar cell usually brings photovoltaics to mind. Indeed, the direct conversion of sunlight to electricity has dominated the realm of solar-energy harvesting for the past 50 years. However, researchers have now begun to re-evaluate the possibilities of thermionic and thermoelectric energy conversion because of some of their attractive features. These processes involve the conversion of heat to electricity, or light to heat to electricity, and have been investigated for over a century. Advances in nanoscale materials and fabrication techniques have now opened new doors for the application of these effects.