Spectral sensitivity of hot carrier solar cells

•Hot carrier and multijunction solar cells are compared with a detailed balance model.•Hot carrier solar cells are less spectrally sensitive than multijuction devices.•Hot carrier solar cells produce morning and evening power closer to the daily peak.•Under 2000× hot carrier devices must target thermalization coefficient <0.1WK−1cm−2.•Spectral insensitivity provides motivation for hot carrier materials development.

In this paper we present detailed balance simulations which determine the material parameters required to produce hot carrier solar cell (HCSC) annual energy yields comparable with that of multi-junction (MJ) systems. We demonstrate that HCSCs are less spectrally sensitive than equivalent MJ devices providing significant motivation for pursuing their development. Spectral variation in a given location over the course of the day and throughout the year means that the HCSC provides more consistent power production. The HCSC can also be developed for a standard reference spectrum and still perform optimally in a variety of locations with different atmospheric conditions, unlike the location sensitive performance of MJ devices. We show that an ideal hot carrier solar cell with bandgap 0.69 eV under 2000× concentration would require a thermalization coefficient <0.1WK−1cm−2 to produce more power over the course of the year than an InGaP/GaAs/Ge triple junction device located at Solar Village in Saudi Arabia. The lowest experimentally demonstrated thermalization coefficient is 9.5WK−1cm−2 indicating that further materials development is required to achieve this target.