Self-powered UV photodetector based on heterostructured TiO2 nanowire arrays and polyaniline nanoflower arrays

A novel self-powered ultraviolet (UV) photodetector with low cost and large area was successfully constructed which was composed of heterostructured arrays of TiO2 nanowires (NWs)/polyaniline nanoflowers (PANI NFs)/TiO2 NWs. The heterostructured arrays of TiO2 NWs/PANI NFs/TiO2 NWs were prepared by combining the hydrothermal and in-situ multiple wet chemical deposition methods. The control methods for the morphology and thickness of PANI on TiO2 NW array were systematically investigated, and their application in UV photodetector was discussed. The results showed that PANI NFs on TiO2 NW array could be obtained by multiple deposition method, and the thickness of PANI NF layer can be adjusted. Furthermore, compared with bare TiO2 NW array, the sensitivity and photocurrent of the UV photodetectors based on TiO2 NWs/PANI NFs/TiO2 NWs heterostructured arrays were both improved greatly at 0 V bias due to the two heterojunctions of n-type TiO2 NWs and p-type PANI NFs, and the intensity of photocurrent could be improved with the thickness of PANI layer increasing.