  A thermophotovoltaic (TPV) energy converter harnesses thermal photons emitted
by a hot body and converts them to electricity. When the radiative heat
exchange between the emitter and PV cell is spectrally monochromatic, the TPV
system can approach the Carnot thermodynamic efficiency limit. Nonetheless,
this occurs at the expense of vanishing extracted electrical power density.
Conversely, a spectrally broadband radiative heat exchange between the emitter
and the cell yields maximal TPV power density at the expense of low efficiency.
By leveraging hot-carriers as a means to mitigate thermalization losses within
the cell, we demonstrate that one can alleviate this trade-off between power
density and efficiency. Via detailed balance analysis, we show analytically
that one can reach near-Carnot conversion efficiencies close to the maximum
power point, which is unattainable with conventional TPV systems. We derive
analytical relations between intrinsic device parameters and performance
metrics, which serve as design rules for hot-carrier-based TPV systems.
