Ultra‐Black Materials: Fundamentals, Design, and Applications

ABSTRACT Ultra‐black materials, characterized by ultrahigh light‐absorption efficiency and black surfaces, have demonstrated tremendous strategic value and application potential in military stealth, aerospace engineering, precision optical instrumentation, and energy conversion. However, their development is currently restricted by an insufficient understanding of the light absorption mechanisms and the lack of systematic design approaches. To address these challenges, this study proposes a comprehensive material‐scene‐characterization ternary research framework and a paradigm evolution model for ultra‐black materials. The fundamental mechanisms underlying ultralow reflectivity, including surface plasmon resonance, light trapping structure, and semiconductor bandgap engineering, were systematically analyzed. Considering the evolution of the research paradigm, a comprehensive overview of representative material systems is provided, covering conventional chemically etched nickel‐phosphorus alloys, carbon nanotubes, emerging top‐down engineered wood structures, and solid‐smoke nanocomposites. This review emphasizes the transformation of characterization techniques from simple reflectivity quantification to multidimensional metrology. Key applications of ultra‐black materials in stray‐light suppression, energy conversion, IR spectral engineering, and auxiliary photocatalysis are discussed. Finally, current challenges and development trends of next‐generation ultra‐black materials are discussed, focusing on artificial intelligence‐assisted inverse design and adaptability to extreme environments. This review aims to provide systematic guidance for the development of next‐generation ultra‐black materials with near‐perfect broadband absorption and outstanding stability.