Back-Surface Passivation of CdTe Solar Cells Using Solution-Processed Oxidized Aluminum.

Although back-surface passivation plays an important role in high-efficiency photovoltaics, it has not yet been definitively demonstrated for CdTe. Here, we present a solution-based process, which achieves passivation and improved electrical performance when very small amounts of oxidized Al species are deposited at the back surface of CdTe devices. The open circuit voltage () is increased and the fill factor (FF) and photoconversion efficiency (PCE) are optimized when the total amount added corresponds to ∼1 monolayer, suggesting that the passivation is surface specific.