Flat-band quantum materials empowering self-adapted ultrabroadband detectors

Blackbody-sensitive room-temperature photodetectors with ultrabroadband response from the short to very long-wave infrared (VLWIR) range are highly desirable for optical communication, industrial gas leakage detection, night vision, and atmosphere surveillance. Although two-dimensional (2D) semiconductors with narrow bandgaps have shown promise in uncooled short and mid-wave infrared (SWIR and MWIR) detection, achieving blackbody responses extending to long-wave infrared (LWIR) or even the VLWIR region at room temperature remains a challenge. Here, we report a bioinspired room-temperature blackbody-sensitive self-adapted ultrabroadband detector utilizing the 2D flat-band quantum material Nb₃I₈, engineered through an electronic and phononic band strategy. Our study reveals that Nb₃I₈ exhibits enhanced SWIR absorption due to electron flat-bands induced high density of states (DOS) and dipole transition probability. Owing to its strong anharmonicity with phonon flat-band characteristics, the phonon propagation is prohibited, which contributes to low thermal conductivity and enhances the heat localization, resulting in a sensitive bolometric response to blackbody radiation from λ = 2.5 μm to 20 μm. Our work not only represents a breakthrough for 2D materials with room-temperature LWIR-VLWIR blackbody detection ability, but also paves the way for implementing blackbody-sensitive ultrabroadband photodetectors by exploiting flat-band quantum materials.