Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal-halide perovskites.

The technique of alloying FA with Cs is often used to promote structural stabilization of the desirable α-FAPbI phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality and enhance the stability have remained elusive. In this study, we advance that understanding by investigating the effect of cationic alloying in CsFAPbI perovskite thin-films and solar-cell devices.

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.

Adherent and Conformal Zn(S,O,OH) Thin Films by Rapid Chemical Bath Deposition with Hexamethylenetetramine Additive.

ZnS is a wide band gap semiconductor whose many applications, such as photovoltaic buffer layers, require uniform and continuous films down to several nanometers thick. Chemical bath deposition (CBD) is a simple, low-cost, and scalable technique to deposit such inorganic films. However, previous attempts at CBD of ZnS have often resulted in nodular noncontinuous films, slow growth rates at low pH, and high ratio of oxygen impurities at high pH.