New Strategy and Excellent Fluorescence Property of Unique Core–Shell Structure Based on Liquid Metals/Metal Halides

Abstract The further applications of liquid metals (LMs) are limited by their common shortcoming of silver‐white physical appearance, which deviates from the impose stringent requirements for color and aesthetics. Herein, a concept is proposed for constructing fluorescent core–shell structures based on the components and properties of LMs, and metal halides. The metal halides endow LMs with polychromatic and stable fluorescence characteristics. As a proof‐of‐concept, LMs‐Al obtained by mixing of LMs with aluminum (Al) is reported. The surface of LMs‐Al is transformed directly from Al to a multi‐phase metal halide of K₃AlCl₆ with double perovskites structure, via redox reactions with KCl + HCl solution in a natural environment. The formation of core–shell structure from the K₃AlCl₆ and LMs is achieved, and the shell with different phases can emit a cyan light by the superimposition of the polychromatic spectrum. Furthermore, the LMs can be directly converted into a fluorescent shell without affecting their original features. In particular, the luminescence properties of shells can be regulated by the components in LMs. This study provides a new direction for research in spontaneous interfacial modification and fluorescent functionalization of LMs and promises potential applications, such as lighting and displays, anti‐counterfeiting measures, sensing, and chameleon robots.