Review of Infrared Nanoantennas for Energy Harvesting

The Sun is the greatest source of energy providing a continuous stream of power; its exploitation has stimulated several approaches and technologies to directly or indirectly achieve renewable energy. New devices, which exploit the thermal radiation created by the Sun, that is transferred in the form of electromagnetic waves into free space, and finally absorbed by the surface of the Earth, are under study. The aim of this contribution is to critically compare advantages and disadvantages of new types of suitable antennas operating at nanometers wavelengths, called nanoantennas, for infrared energy harvesting, focusing on the state of the art and its perspectives.