A self-powered high performance UV-Vis-NIR broadband photodetector based on β-Bi₂O₃ nanoparticles through defect engineering

Broadband photodetectors are essential for military and civilian applications. Metal oxides have been widely investigated as photodetectors due to their facile synthesis, low cost and good stability. However, the inherent wide-bandgap allows them to mainly absorb light in the ultraviolet (UV) region, limiting their application in broadband photodetectors. Herein, a self-powered ultraviolet-visible-near infrared (UV-Vis-NIR) photodetector based on β-Bi₂O₃ nanoparticles is reported, owing to the intrinsic defects introduced through low-temperature thermal oxidation of bismuth (Bi), which induces light absorption in the UV-Vis-NIR region. Moreover, the device exhibits high-efficiency detection performance in the UV (365 nm) to NIR (850 nm) region, especially with a high responsivity of 29.92 mA W⁻¹, a high specific detectivity of 7.46 × 10¹⁰ Jones and a fast response time of 20/70 ms under light illumination with a wavelength of 365 nm. These results demonstrate that β-Bi₂O₃ nanoparticles are promising for high-efficiency broadband photodetector applications. This work also opens up a new strategy for constructing broadband photodetectors based on metal oxides.