Multiple quantum well top cells for multijunction concentrator solar cells

High efficiency quantum well GaAs solar cells have been successfully applied in commercial multijunction concentrator cells to increase the absorption in the infrared and provide variability of the absorption edge to optimise energy harvesting. Multiple quantum well (MQW) top cells can further improve the performance of multijunction solar cells since the absorption edge of top and middle subcells can be tuned with the MQWs to maximize the efficiency. Also, our simulations show that photon coupling resulting from the radiative dominance of the MQW top cell can make the multijunction cell less sensitive to variations in the incoming spectrum, thus further improving energy harvesting. New results on the characterisation of a novel MQW top cell will be presented along with electro- and photo-luminescence studies relevant to the photonic coupling.