Performance of State-of-the-Art CdTe-Based Solar Cells: What Has Changed?

The open-circuit voltage (
V
_OC
) of polycrystalline state-of-the-art, arsenic-doped CdSeTe/CdTe solar cells has reached 917 mV, and the record cell efficiency has been gradually increasing. However, there is a significant difference in performance between the current CdTe-based solar cells and single-crystal GaAs cells that have a comparable band gap. The largest contribution to this difference in performance is the voltage. Between 1993 and 2023,
V
_OC
of CdTe-based solar cells improved by ∼143 mV when an appropriate adjustment was made for the band gap. This value is still about ∼180 mV below the best GaAs cells. The potential for even higher CdTe efficiencies will likely require a combination of incorporation of front-contact improvements, optimization of thickness, selenium profile, doping, and grain-boundary passivation of the absorber, better passivation of the rear interface, and assurance of back-contact conductivity and band alignment.