While crystalline silicon accounted for two thirds of the PV market in 2014, cadmium telluride (CdTe) photovoltaic (PV) modules are becoming increasingly competitive with continued improvements in efficiency and reduction in price. This project will contribute to enabling 24% efficient CdTe cells by improving surface and interface recombination in the devices. Surface and interface recombination, which is the loss of photo-generated carriers before they are collected, becomes more detrimental to CdTe device performance as carrier lifetime increases. This project will develop effective surface passivation for CdTe and carrier selective contacts for higher efficiency, improved reproducibility, and increased stability.
Researchers will study surface and interface defects and develop passivation strategies to minimize recombination. The team will then optimize carrier selective contacts at the front and back interfaces to maximize carrier collection while maintaining low optical absorption at the front and maximize good hole transport at the back without the use of copper.
CdTe has the potential to have the lowest levelized cost of energy of any photovoltaic technology. In order to achieve this, this project will solve one of the big materials science challenges that limits efficiency – interface recombination. Tackling this issue will provide the opportunity to replace cadmium sulfide, cadmium chloride, and copper to increase reproducibility and stability. This will benefit established CdTe manufacturers and new start-up companies.