Epitaxial Growth of Core/Shell Metal Halide Perovskite Nanocrystals for Optoelectronic Applications

ABSTRACT Metal halide perovskite nanocrystals (PNCs) have demonstrated broad application prospects in optoelectronic devices, owing to their remarkable advantages, including excellent photoluminescence quantum yields (PLQY) and tunable emission wavelengths. However, their limited stability under external environmental factors has severely restricted their practical applications and commercialization. Epitaxial growth of core–shell structures, through precise control of the ordered deposition of the shell layer on the surface of the core crystals, forms a unique lattice‐coherent heterojunction interface. This approach can not only effectively passivate surface defects and suppress non‐radiative recombination but also regulate carrier behavior through band‐structure engineering, significantly enhancing the optoelectronic properties and environmental stability of the materials. In this review, we systematically describe the recent developments on the epitaxial growth of perovskite core–shell nanocrystals. It focuses on introducing the mainstream synthesis methods for the epitaxial growth of shell structures. It delves deeply into the roles of epitaxial growth in multi‐level stabilization mechanisms such as surface defect repair, band‐structure regulation, and bond‐energy shielding. Additionally, we summarize the applications of epitaxial core–shell structures across various devices. It provides an outlook on future challenges and development directions, offering important guidance for the development of high‐performance, high‐stability perovskite optoelectronic devices.