CsZnPbBr3/ZnS core/shell perovskite nanocrystals for stable and efficient white light-emitting diodes

The widespread applicability of perovskite nanocrystals (PeNCs) is impeded by their intrinsic instability. A promising solution is utilizing robust chalcogenides as a protective shell to shield the sensitive luminescent cores from the external environment. However, the inferior structural stability and surface lability of PeNCs usually lead to perovskite phase transition during shell growth. Herein, we introduced smaller Zn ions to partially replace Pb ions in perovskites, which reduces the Pb-X bond length and enhances the Pb-X bond energy for inner lattice stabilization. Simultaneously, extra oleylammonium bromide (OAmBr) was added to protect the labile surface of PeNCs by compensating for the detachment of ligands and the loss of surface Br ions. As a result, the dual strategies enable the epitaxial growth of a ZnS shell and significantly enhance the chemical stability of CsZnPbBr