Hot carrier solar cells: Achievable efficiency accounting for heat losses in the absorber and through contacts

The hot carrier solar cell enables the photovoltaic efficiency limit to be approached by tapping into what are normally heat losses. Previous models neglected thermalization in the absorber and assumed ideally energy selective contacts that allow minimum heat losses upon carrier extraction. The proposed improved model includes both realistic contacts and thermalization rates. The heat flux due to carrier extraction is computed. Results show that spectrally broad semiselective contacts are compatible with an efficiency exceeding the single junction limit, which would considerably facilitate the realization of the device.(C) 2010 American Institute of Physics. [doi:10.1063/1.3489405]