Tannic Acid Modified Single-Walled Carbon Nanotube/Zinc Oxide Nanoparticle Thin Films for UV/Visible Semitransparent Photodiode-Type Photodetectors

Graphical Steps in the right direction : ZnO/CNT (carbon nanotube) heterojunctions were prepared by non-covalent modification of CNTs using a simple spraying method and subsequent annealing. This heterojunction was constructed without affecting the film sheet resistance and transmittance, and the non-covalently modified CNT showed a substantial improvement in the recession time relative to the pristine CNT and improved the device with higher photoresponsivity and detectivity at 365 nm. Flexible electronic devices have received significant attention in recent years as a result of their flexibility and portability. Carbon nanotube (CNT) films could serve as a promising material for photodetection because of their broad absorption spectral coverage. In this research, vertical ultraviolet (UV) to visible (UV/Vis) detectors based on tannic acid functionalized carbon nanotube/zinc oxide (TCNT/ZnO) heterojunctions were prepared by a simple spraying method. The TCNT electrode had excellent photoelectric properties with a sheet resistance of 40.6 Ω/sq and transmittance of 80.4 % at 550 nm, and the resulting TCNT/ZnO device could achieve photocurrent of 3.0 mA at 360 nm in the UV range, a recession time of 8.05 s, photoresponsivity of 7.12 A/W, and detectivity of 25.2×10 11 Jones. As a comparison, for the pure CNT electrode with a sheet resistance of 45.5 Ω/sq and transmittance of 79.6 % at 550 nm, the CNT/ZnO photocurrent was only 0.6 mA at 360 nm, with a recession time of 17.25 s, photoresponsivity of 1.00 A/W, and detectivity of 3.4×10 11 Jones. The prepared device was also able to operate stably after 1000 mechanical bending tests and maintained more than 95 % detectivity, providing a feasible path for the generation of carbon nanotube based photodetector devices.