TiO2 nanoarrays/Au nanoparticles/PProDOT-Py hybrid heterojunction UV photodetector

In this paper, a novel D-A-D type conducting polymer (PProDOT-Py) with pyridine as acceptor unit and 3,4-propanedioxythiophene as donor unit was prepared for heterojunction ultraviolet (UV) photodetector based on TiO ₂ NRs/Au NPs. The effect of PProDOT-Py on the UV photodetection properties was deeply discussed. The results showed that PProDOT-Py was unevenly dispersed on TiO ₂ NRs in the form of cross-linked network, and there were coordination bonds between TiO ₂ NRs and PProDOT-Py. The matching of the energy levels between PProDOT-Py and TiO ₂ was helpful for formation of heterojunction hybrid.The maximum rectification ratio of TiO ₂ NRs/Au NPs/PProDOT-Py was 54 under bias voltage of −2 to 2 V, implying that the p-n heterojunction in the internal structure of TiO ₂ NRs/Au NPs/PProDOT-Py. The Fermi level of TiO ₂ NRs was changed by the presence of PProDOT-Py, which generated the p-n heterojunction for producing strong inherent electric field. In addition, D* and I _photo/I _dark of UV photodetector based on TiO ₂ NRs/Au NPs/PProDOT-Py were 1.067 × 10 ¹³ Jones and 17857.14 (2 V), respectively. Under the condition of self-power supply, the device has an ultrafast response time of 0.06 s.