Highly Stable CsPbX₃/PbSO₄ Core/Shell Nanocrystals Synthesized by a Simple Post‐Treatment Strategy

Abstract

All‐inorganic lead halide perovskite (CsPbX3, X = Cl, Br, I, or their mixture) nanocrystals (NCs) have recently emerged as a promising photoelectric material; however, developing highly stable CsPbX3 NCs still remains a challenge due to their intrinsic ionic nature. This work presents a simple and facile post‐treatment strategy to encapsulate CsPbX3 NC with PbSO4 nanoshell at single‐particle level. Compared to pristine CsPbX3 NCs, the as‐prepared CsPbX3/PbSO4 NCs exhibit significant enhancement in the optical properties. Benefiting from the efficient protection of inert PbSO4 nanoshell, the obtained CsPbX3/PbSO4 core/shell NCs demonstrate great stability against polar solvents, including ethanol and acetone, and light irradiation. Furthermore, anion‐exchange reaction is strongly restricted upon the encapsulation of PbSO4 shell. This work provides an alternative approach for the synthesis of highly stable CsPbX3 NCs, and paves a new way for the preparation of core/shell heterostructures based on lead halide perovskite NCs.

Perovskite Quantum Dots with Ultrahigh Solid-State Photoluminescence Quantum Efficiency, Superior Stability, and Uncompromised Electrical Conductivity

“…The results described here are apparently similar to those obtained by the post-treatment of Octam-SO 4 , except that our treatment time is much longer. In fact, by choosing a different source of SO 4 2– , and on purposely lowering the dosage, we managed to slow down the reaction rate, which brings at least two benefits.…”

“…Cao et al reported a quick post-treatment using octylammonium sulfate (Octam-SO 4 ) which helps to enhance the PLQE and the stability of CsPbX 3 (X = Cl, Br) QDs. 31 Later, we proposed a surface sacrificial reaction using octylammonium phosphate, which delivered CsPbBr 90% and superior overall stability. 32 We found that, on one hand, the bonding between oxysalt ions and the lowcoordinated Pb not only passivates surface defects but also provides a protecting shell on the surfaces.…”

“…Very recently, strategies of surface lead oxysalts emerged. Cao et al reported a quick post-treatment using octylammonium sulfate (Octam-SO 4 ) which helps to enhance the PLQE and the stability of CsPbX 3 (X = Cl, Br) QDs . Later, we proposed a surface sacrificial reaction using octylammonium phosphate, which delivered CsPbBr 3 QDs with a PLQE over 90% and superior overall stability .…”

Switchable Anion Exchange in Polymer-Encapsulated APbX3 Nanocrystals Delivers Stable All-Perovskite White Emitters

“…Strategies have been designed to prevent anion exchange and/or to stabilize MHP NCs against polar solvents, including encapsulation of NCs in matrixes made of metal oxides (e.g., PbSO 4 , SiO 2 , TiO 2 , Al 2 O 3 ), inorganic salts (SrBr 2 ), a mixture of metal oxides and inorganic salts, metal organic hybrids (e.g., metal organic frameworks), and polymers. ,,− Polymers are appealing as they can switch their chains from an extended coil state to a collapsed globule state when the characteristics of the solvent change. In its globule state, a polymer can act as a protecting layer that shields the NCs from their surroundings, making them unreactive.…”

Microemulsion‐Induced Stable CsPbBr3/PbWO4 Nanocrystals for Light‐Emitting Diodes

“…For example, Zhang and coworkers reported a simple post-treatment strategy to encapsulate CsPbX 3 NCs with PbSO 4 nanoshell through mixing octylammonium sulfate (OctAm-SO 4 ) with CsPbX 3 NCs, demonstrating great stability against polar solvents and irradiation. [16] However, there was a lack of LED devices in this report, which may be ascribed to the poor dispersion of the as-treated CsPbX 3 NCs that cannot be applied in the emissive layers of LEDs.…”