Kinetics‐Controlled Interfacial Synthesis of Janus and Patchy Heterostructures Based on Perovskite Nanocrystals

Abstract Heterostructures integrated by diverse material featuring nanocrystals (NCs) tunable properties and functions are of great interest. However, to rationally design and precisely control the heterostructures in multiple shapes still remains a tremendous challenge. In this work, the nucleation of SiO₂ nanoparticles is manipulated via a kinetics‐controlled water–hexane interfacial reaction system to construct Cs₃Cu₂I₅/SiO₂ heterostructures, which can be well controlled in Janus and patchy morphology. In this interfacial reaction, the evolution of Cs₃Cu₂I₅ NCs and the intrinsic formation mechanism of the heterostructures are investigated. It is observed that the Cs₃Cu₂I₅ NCs on the interface undergo a morphology transformation driven by ligand loss and exposed facets evolution. Increased wettability between Cs₃Cu₂I₅ and SiO₂ favors the formation of Cs₃Cu₂I₅/SiO₂ heterostructures. The key to this strategy is to break the rule of thermodynamic domination in reaction by kinetics manipulation when constructing the patchy heterostructure. To be noted, an increased stability is conferred on the resultant heterostructure product compared to naked perovskite NCs. This work enables to better control the complicated heterostructure configurations and understand their formation mechanism.