High-performance flexible UV detector based on Bi-ZnO nanoflowers/PEDOT-CH2OH via synergistic Co(IO3)2 interface polarization and oxygen vacancy enrichment

Advancements in wearable electronics have driven demand for flexible, self-powered UV photodetectors, yet the efficient separation and transport of carriers remain critical challenges to realizing their full potential. This study constructs a high-performance flexible self-powered UV detector based on an electrochemically doped Bi-ZnO nanoflowers/PEDOT-CH 2 OH p-n heterojunction, further modified with a Co(IO 3 ) 2 layer. Bi 3+ doping introduces oxygen vacancies to enhance carrier separation, synergizing with the built-in electric field within the heterojunction. The spontaneous polarization of Co(IO 3 ) 2 enhances this electric field, optimizing band alignment and suppressing recombination, while hydroxyl groups in PEDOT-CH 2 OH stabilize the oxygen vacancies. The piezoelectric response of ZnO is not prominent in this device, as its modulating effect is overshadowed by the dominant charge separation mechanism based on doping and interfacial polarization. Through synergistic bandgap engineering, defect control, and interface modification, the optimized device achieves a responsivity of 2.05 mA/W, a specific detection rate of 3.25 × 10 10 Jones, and an ultrafast response time of 54 ms under 365 nm UV illumination. The detector exhibits exceptional flexibility, stability, and selectivity, maintaining high performance through 2500 bending cycles, indicating significant potential for application in flexible, wearable UV sensing.