Colloidal Photonic Crystals for Anti-counterfeiting: Design Strategies and Application Prospects

Colloidal photonic crystal (PC)-based security materials, which leverage their distinctive structural colors, tunable photonic bandgaps, and user-friendly authentication mechanisms, demonstrate remarkable potential for advanced anti-counterfeiting applications. This review systematically examines recent progress in colloidal PC-enabled security technologies. Firstly, it outlines fabrication strategies for colloidal PCs tailored for security purposes, covering visually detectable features, covert systems, and emerging material platforms. Subsequently, it critically evaluates the design strategies, synthesis methods, security levels, and authentication techniques of these three categories of colloidal PC-based security materials. The paper ends with a discussion on the development prospects and key challenges in this field, providing theoretical insights and technical guidance for the construction of next-generation anti-counterfeiting material systems characterized by high security, dynamic responsiveness, and multi-modal functionalities.