The growth of methylammonium lead iodide perovskites by close space vapor transport.

Vapor deposition processes have shown promise for high-quality perovskite solar cells with potential pathways for scale-up to large area manufacturing. Here, we present a sequential close space vapor transport process to deposit CHNHPbI (MAPI) perovskite thin films by depositing a layer of PbI then reacting it with CHNHI (MAI) vapor. We find that, at = 100 °C and pressure = 9 torr, a ∼225 nm-thick PbI film requires ≥125 minutes in MAI vapor to form a fully-reacted MAPI film.

Nano-folded Gold Catalysts for Electroreduction of Carbon Dioxide.

The local structure and geometry of catalytic interfaces can influence the selectivity of chemical reactions. Selectivity is often critical for the practical realization of reactions such as the electroreduction of carbon dioxide (CO). Previously developed strategies to manipulate the structure and geometry of catalysts for electroreduction of CO involve complex processes or fail to efficiently alter the selectivity.

Overcoming Carrier Concentration Limits in Polycrystalline CdTe Thin Films with In Situ Doping.

Thin film materials for photovoltaics such as cadmium telluride (CdTe), copper-indium diselenide-based chalcopyrites (CIGS), and lead iodide-based perovskites offer the potential of lower solar module capital costs and improved performance to microcrystalline silicon. However, for decades understanding and controlling hole and electron concentration in these polycrystalline films has been extremely challenging and limiting. Ionic bonding between constituent atoms often leads to tenacious intrinsic compensating defect chemistries that are difficult to control.

A new photoelectrochemical test cell and its use for a combined two-electrode and three-electrode approach to cell testing.

This paper describes the design, assembly, and operation of a photoelectrochemical (PEC) test cell that is relatively easy to construct and well suited for testing photoelectrode/counterelectrode combinations in a reproducible manner. The design of the cell permits measurements to be made in both two-electrode and three-electrode arrangements. The benefits of conducting both two-electrode and three-electrode measurements are illustrated using data obtained from the new test cell for a PEC system based on a polysulfide electrolyte, CdSe(0.