Photovoltaic devices based on perovskites hold the potential of thin, light structures and very high efficiencies. However, the instability of perovskites in air leads to very short device lifetimes (on the order of hours), and thus silicone-based solar cells continue to dominate the market. Strategies to encapsulate perovskite cells to protect against air exposure have been successful in extending their lifetimes, and a number of companies are developing commercial products, but challenges remain.

Researchers from Roy Gordon’s lab have developed a chemical vapor deposition (CVD) method to create smooth, uniform, cuprous halide hole-transport layers (HTLs) for thin film photovoltaic devices. The semiconductors CuX (X = Cl, Br, or I) are high-mobility p-type transparent conductors. However, commercial device-quality CuX films cannot easily be deposited via existing methods. CVD is an established and scalable process that provides excellent uniformity over large areas and allows the films to be deposited directly onto the perovskite layer. The researchers have shown that this method produces conductive, pinhole free, uniform, and optically transparent films. This scalable method for producing high quality HTLs is a key step in realizing the commercial potential of perovskite solar cells.

This work was published in ACS Chemistry of Materials.