3D Pyramid‐Structured MXene‐Films for Sub‐THz to Mid‐IR Full‐Band Absorption

ABSTRACT High‐performance broadband absorbers are critical for radar stealth, 6G, and high‐precision detection by absorbing incident waves, suppressing scattering, and enhancing signal purity. However, existing approaches struggle to achieve sub‐THz to mid‐IR full‐band absorption, hampered by ultra‐broadband impedance matching challenges and intrinsic material absorption limits. Here, we design a novel 3D pyramid‐structured MXene‐films absorber, which constructs planar MXene‐films into a 3D pyramidal array on a 3D‐printed conformal substrate with Ag‐film reflective coating. This design extends the design degrees of freedom for 2D thin films, achieves a giant enhancement in absorption, and realizes near‐perfect absorption across the sub‐THz to mid‐IR band with excellent robustness (0–75° oblique incidence, TE/TM polarization). Experimental and simulated results demonstrate an impressive operating bandwidth from 0.1 – 20 THz, where the reflection loss (RL) remains below ‐20 dB (A > 99%). Especially, an unprecedentedly excellent average absorption intensity of −52.88 dB (A > 99.999%) is obtained in the 0.5 – 20 THz. This work offers a generalizable pathway toward exceeding conventional absorption limits and opening new opportunities in THz photonics, infrared stealth, and 6G communication technologies.