Colloidal Photonic Crystals: Advanced Assembly Strategies and Frontier Optical Applications

ABSTRACT Colloidal photonic crystals, characterized by their periodic nanostructures and unique photonic bandgap properties, have attracted considerable interest due to their potential in rapid sensing, ultrasensitive detection, and next‐generation optical devices. The self‐assembly of colloidal latex particles provides an effective approach for constructing functional colloidal photonic crystals. In this review, recent advances in the self‐assembly of colloidal photonic crystals are comprehensively analyzed, with particular attention given to the correlation between assembly mechanisms and functional device integration. A diverse range of assembly strategies of spray coating, inkjet printing, 3D printing, microfluidic, electrospinning, capillary‐assisted assembly, and wettability‐assisted assembly are systematically categorized and evaluated in terms of their assembly precision, scalability, and structural versatility. Frontier optical applications, including structural coloration, display technology, bioinspired actuator, sensing and detection platform, thermal management system, and optical waveguide device, are discussed to illustrate the practical relevance and multifunctionality of colloidal photonic crystals. By linking novel assembly strategies with device‐level functionalities, new insights are provided to guide future research toward scalable fabrication and real‐world application of colloidal photonic crystal systems.