Surface and Interface Engineering for Highly Stable CsPbBr₃/ZnS Core/Shell Nanocrystals

Abstract

Shelling with chalcogenides on the surface of lead halide perovskite (LHP) nanocrystals (NCs) is believed to be an effective approach to increase their stability under high-moisture/aqueous conditions, which is important for LHP NC-based optoelectronic devices. However, it is still a challenge to prepare highquality LHP/chalcogenide core/shell NCs with moisture/aqueous stability. In this work, a surface-defect-induced strategy is carried out to facilitate the adsorption of Br − ions and subsequently Zn 2+ ions to preform a bipolar surface, which reduces the energy barrier at the CsPbBr 3 /ZnS interface and promotes the epitaxial growth of the ZnS shell layer. The aqueous stability of the as-received NCs shows an increase of over 12 times compared to that of the original one. Likewise, Mn 2+ ions are introduced to further reduce the geometric symmetry mismatch and defect density at the CsPbBr 3 /ZnS interface. Interestingly, aqueous stability characterizations illustrate negligible degradation even after 230 min of ultrasonication, suggesting their outstanding stability. This work proposes an effective approach to prepare high-quality LHP/chalcogenide core/shell NCs, which possess great potential in the fabrication of stable optoelectronic devices.

Enhancement of Photoluminescence in CsPbBr3 Nanocrystals with 1-Octanethiol by Light Illumination for Potential Emitting Applications

“…Lead halide-based perovskite nanocrystals (NCs) are promising candidates for optoelectronic and photonic applications due to their unique structures and properties. − Strong photoluminescence (PL) in perovskite NCs makes them particularly emerging for light-emitting applications. , PL performance is strongly dependent on the NC surface or surroundings , due to the fact that unsaturated surface bonds provide nonradiative recombination channels for photogenerated holes and electrons. Many efforts have been devoted to passivating the unsaturated bonds, e.g., by capping appropriate organic ligands − or adding inorganic ZnS shells , as an effective way to improve the PL performance of CsPbX 3 NCs. On the other hand, the addition of some organic molecules, such as electron or hole acceptors, into CsPbX 3 NCs will weaken their PL intensities and lead to a charge separation state, − which is crucial for photocatalytic and photovoltaic applications.…”