Photoelectrochemical ultraviolet photodetector by anodic titanium dioxide nanotube layers

A prototype ultraviolet (UV) photodetector based on photoelectrochemical (PEC) cell from material synthesis up to assembly was demonstrated in this work. Self-organized titanium dioxide (TiO2) nanotube layers (1 and 5 μm thicknesses) prepared by electrochemical anodization were applied as the sensing layer in the photodetector. A printed circuit board (PCB) platform with physical size of 2 cm × 2 cm was designed to mount the sensing layer. The photodetector system comprised of a sandwich structure can be described as glass/ITO/electrolyte/TiO2 nanotube layer/Ti/PCB platform. For this system, a low applied voltage of 0.5-1 V was required to drive the photodetector. TiO2 nanotube layers have shown positive photoresponse in the entire UV spectral region (λ = 250-400 nm, classified as UV-A, B and C). In particular, the highest response with >850 sensitivity, and responsivity of ≈740 mA/W had been achieved by the 5 μm TiO2 nanotube layer for detection in the UV-A region, and the respective rise and decay time were 0.88 and 1.28 s. This work shows that the sandwich structure PEC cell UV photodetector with TiO2 nanotube layer as sensing layer is stable, highly sensitive and provides rapid response. Such platform can be potentially applied for other sensing materials as an efficient photodetector.