Facet‐Engineered (100)‐Oriented MoO 2 Nanoribbons for Broadband Self‐Powered Photodetection

Abstract Broadband photodetection plays a vital role in aerospace applications, biomedical imaging, and advanced communication systems. While molybdenum dioxide (MoO 2 ) exhibits exceptional electrical conductivity, carrier mobility, and environmental stability, its potential for photodetection has remained unrealized, with existing literature reporting negligible optoelectronic responses. Here, we unlock latent photoresponsivity of MoO 2 by facet engineering, demonstrating that exposing the (100) crystallographic plane activates its intrinsic photoelectric conversion. Using atmospheric‐pressure chemical vapor deposition, we successfully fabricated large‐area arrays of (100)‐oriented MoO 2 nanoribbons. The resulting flexible photodetector on polyethylene glycol terephthalate (PET) substrate exhibits unprecedented performance, achieving broadband detection from visible to long‐wave infrared (LWIR: 0.5–10.5 µm) range without external bias. The device demonstrates a fivefold enhancement in responsivity compared to rigid substrate configurations, reaching 107.31 mA W −1 at 10.5 µm wavelength with an exceptionally low noise‐equivalent power ( NEP ) of 6.64 pW Hz −0.5 , surpassing all self‐powered photodetectors reported to date. Comprehensive characterization reveals distinct photoresponse mechanisms: photothermoelectric effects dominate on silicon substrates, while photobolometric behavior prevails in flexible configurations. These findings not only resolve the previously observed photoresponse limitations in MoO 2 but also establish facet engineering as a general approach for developing high‐performance photodetectors based on metallic oxides, with significant implications for flexible optoelectronic applications.