Interface Engineering for 25% CdTe Solar Cells

Buffer layers, such as CdS and MgxZn1–xO (MZO), are critical for CdTe and other thin film polycrystalline solar cells. A ternary compound, such as MZO, allows for interface engineering by adjusting composition, bandgap, and doping to manipulate barriers and recombination to enhance thin film efficiencies toward 25%. Here, theoretical studies demonstrate the enormous impact of front interface offset and emitter doping have on device performance. The results reveal it is possible to achieve 25% device efficiency with open-circuit voltage >1 V, even for 105 cm/s recombination velocity, provided the interface offsets and doping are properly engineered.