Hot carrier solar cell as thermoelectric device

Improvement of solar cell efficiency beyond the Shockley–Queisser limit requires introduction of new physical concepts. One such concept is hot carrier solar cell, proposed more than three decades ago and still not impressively demonstrated in experiment. Here we show that hot carrier solar cell may be considered as thermoelectric device based on Seebeck effect. This enables one to describe the operation of hot carrier solar cell in a simple way. We fabricated a prototype of the hot carrier solar cell showing open circuit voltage at room temperature larger than the band gap in the absorber material. Extrapolation of open circuit voltage to absolute zero temperature results in barrier height depending on light intensity, interpreted by splitting of quasi-Fermi levels between the regions of different carrier temperature. Properties of the prototype solar cell may be described by kinetic transport theory as well as from the point of view of the thermoelectric theory.