Dual‐Bidirectional Optoelectronic Bi ₂ O ₂ Se Single Crystal Enabled by Site‐Selective O‐Se Substitution for Self‐Contained Scene Perception‐Recogni

ABSTRACT

Simultaneous integration of electrical bipolarity and bidirectional photoresponse enables enhanced dynamic scene perception, recognition, and interaction within a single device, represents a formidable yet actively pursued challenge, motivated by applications in intelligent autonomous driving, augmented reality, and related advanced technologies. Here, we report a site‐selective O‐Se substitution strategy, yielding, for the first time, enables electrically and optically bipolar charge transport in a single‐crystalline Bi ₂ O ₂ Se 2D semiconductor. Their‐based filed‐effect transistors (FETs) show balanced ambipolar (P/N‐type) carrier transport with a record‐level of I _ON / I _OFF ratio over 6000, and broadband positive and negative photoconductivity (PPC/NPC) from 300 to 1400 nm selectively activated under opposite polarity bias conditions. This dual‐bidirectional optoelectronic performance is attributable to a wavelength‐dependent oxygen adsorption–desorption process that dynamically modulates the electronic band structure and charge transport characteristics. Moreover, we successfully demonstrate its integrated applications in high‐dimensional secure optical communication, round‐the‐clock motion detection and recognition (MDR), and context‐aware interaction to dynamic events. The result demonstrates seamless integration of multi‐wavelength spectral sensing, in‐sensor computing, and hardware‐rooted secure communication within such Bi ₂ O ₂ Se devices, establishing a foundation for next‐generation optoelectronic technologies.