Optical determination of thermoelectric transport coefficients in a hot-carrier absorber

Hot-carrier solar cells offer potential for enhancing the energy-conversion efficiency of photovoltaic devices. Transport properties of such systems remain largely unexplored but could hinder their efficiency. In this work, we develop a suitable framework for describing the thermoelectric ambipolar transport of photogenerated hot carriers and derive analytical expressions for the ambipolar transport coefficients that are valid even in the degenerate case. We demonstrate that these transport coefficients can be measured from hyperspectral photoluminescence imaging. We validate this experimental determination by showing its consistency with the Boltzmann transport equation in the relaxation-time approximation.