Traditional optoelectronic detection systems suffer from the functional separation of sensing and computing, low data transmission efficiency, and insufficient real-time performance for dynamic scene detection. To address these limitations, BiOI/TiO₂ heterojunction film was synthesized via a two-step hydrothermal route, and Pt/BiOI/TiO₂/FTO self-powered photodetector (PD) was accordingly fabricated in this work. The morphological features, crystal structure, band structure, and optoelectronic response characteristics were characterized. The results show that the PD exhibits excellent photoresponse characteristics to ultraviolet (UV)-blue light in the 300-475 nm wavelength range under zero bias. Under 385 nm illumination, the PD achieves a responsivity (R) of 0.68 A/W, a detectivity (D*) of 7.0 × 10¹¹ Jones, an external quantum efficiency (EQE) of 225%, and a linear dynamic range (LDR) of 99 dB. Owing to the synergistic effects of the Z-scheme band configuration, built-in electric field, and the interface potential well, the device exhibits a distinctive nonlinear time-domain photocurrent response under UV light illumination, consisting of an instantaneous sharp peak, exponential decay, and slow steady-state saturation. Leveraging this unique photoelectric characteristic, software simulations were performed to validate the practical applications of PD arrays in moving target trajectory recognition and dynamic ultraviolet image encryption. Real-time tracking of directional motion trajectories was realized, and gradual concealment of encrypted text “TJUT” within 5.5 s was achieved through dynamic imaging. This study demonstrates that the fabricated BiOI/TiO₂ self-powered PD integrates in-situ sensing and computing capabilities, rendering it promising for advanced applications including intelligent perception, secure communication, and dynamic image.

Optoelectronic logic gate devices (OELGD) utilizing photons as input signals hold great potential for high-speed, high-capacity data transmission and processing, offering a promising solution to the “electronic bottleneck” problem. Wavelength-controlled bipolar photoresponse photodetectors (PDs) are critical for advancing such as OELGDs. In this study, BiOI/TiO₂ heterojunctions were constructed by depositing two-dimensional layered BiOI nanoflakes onto TiO₂ thin film via a solvothermal method. Leveraging the large conduction-band and valence-band offsets of the heterojunction, wavelength-tunable dual-polarity photocurrent was achieved by modulating barrier tunneling and recombination processes of photo-generated carriers at the interface under ultraviolet (UV) and visible light illumination. The stoichiometric ratio of BiOI was adjusted by introducing glycerol during synthesis, which regulated the BiOI conduction-band position and consequently modulating the conduction-band offset of BiOI/TiO₂ heterojunction. The optimized heterojunction with 1 mL glycerol addition exhibited wavelength-controlled bipolar photoresponse across the UV–visible dual bands over a broad voltage range (‒0.5 to +0.5 V). Using UV and visible light as input signals, five basic logic gates (“AND”, “OR”, “NAND”, “NOR”, and “NOT”) were implemented in a single BiOI/TiO₂ heterojunction PDs. Furthermore, by harnessing this UV–visible logic functionality, in-sensor processing of Chrysanthemum carinatum images was realized, simulating the biological phenomenon where bees perceive UV nectar guides on flower petals that are invisible to humans. These results demonstrate the potential of BiOI/TiO₂ devices as innovative components for reconfigurable OELGDs.