Nano-gap TPV generation of electricity through evanescent wave in near-field above emitter surface

摘要

Nano-gap thermophotovoltaic (Nano-Gap TPV) generation of electricity through evanescent wave existing only in. a near-field above an emitter surface has been investigated experimentally using a GaSb cell. Through the cell, radiation with wavelength less than 1.8 mu m is converted into electricity. With decreasing gap between the emitter and cell surfaces, the output power, first increases, and then is maintained at constant since the view factor for the propagating radiation becomes close to unity. On further decrease in gap from about 3 mu m, evanescent effect for long wavelength radiation becomes remarkable, resulting in enhancement only of heat transfer from the emitter to the cell. However, under the condition of the gap less than 1 mu m, the output power increases with decreasing gap; that is, the evanescent wave for wavelength less than 1.8 mu m contributes to generation of electricity.