Current-voltage curves and operational stability in hot-carrier solar cell

Abstract

Current-voltage (I-V) curves and operational stability of hot-carrier solar cells are studied by a non-equilibrium theory considering three characteristic timescales of the hot-carrier dynamics (timescales for the extraction, equilibration, and thermalization). We find a hysteresis behavior in the I-V curves of high-efficiency hot-carrier solar cells, which could result in an operational instability. For practical application, we point out two types of instabilities that can degrade the device efficiency: one is intrinsic in a single cell and the other arises when plural cells are series-connected. It is also found that particle-number non-conserving processes, Auger recombination and impact ionization, increase the stability, showing an advantage of using a semiconductor material with a large Auger recombination coefficient for the light absorber.