Enhanced stabilization of inorganic cesium lead triiodide (CsPbI3) perovskite quantum dots with tri-octylphosphine

In recent years, significant attention has been paid to perovskite materials. In particular, lead triiodide-based perovskites have exhibited superb optoelectronic properties. Enhancing the stability of these materials is an essential step towards large-scale applications. In this study, by simply adding trioctylphosphine (TOP) as part of the post-synthesis treatment, we significantly enhance the stability of CsPbI3 quantum dots (QDs) in the solution phase, which otherwise decay rapidly in hours. For CsPbI3 QDs treated with TOP, the absorption and photoluminescence emission properties are unchanged over the course of weeks, and the quantum yield remains almost constant at 30% even after 1 month. The morphologies of both treated and untreated QDs are initially cubic; however, the treated QDs largely maintain their initial size and shape, while the untreated ones lose size uniformity, which is a sign of degradation. Infrared spectroscopy and X-ray photoelectron spectroscopy confirm the presence of P in the TOP-treated QDs. We insights that help to resolve the intrinsic instability issue of triiodide perovskite materials and devices.