There is an increasing interest in harvesting photoejected electrons for highly sensitive photodetectors, by interfacial engineering rather than the classic semiconductors. However, the widely employed device structures involving a p - n junction that causes photogenerated electron-hole separation to enhance the response are usually complex with a high fabrication challenge. Here, we present TiO 2 -based highly efficient ultraviolet (UV) photodetection by achieving its nanocrystal assembled film having high surface defects. The sol-gel derived TiO 2 films have been subjected to a post-growth annealing at 500 °C in air (SA) and vacuum (SB) and one subjected to UV treatment (SC) to tune the surface defects. The UV photoresponse results show that the nanocrystal assembled UV cured TiO 2 film shows as high as 1.7 × 10 3 UV-to-visible rejection ratio and photo-to-dark current ratio of 1.2 × 10 4 under 10 V bias and 10 μW incident light power. Most interestingly, unprecedently high photo-to-dark current ratio of the order of ∼10 4 at as low as 1 V bias condition and only 10 μW incident light without device fabrication has been observed. Moreover, the films show stable response cyclibility under UV radiation. Therefore, simple UV curing improves UV photoresponse properties of TiO 2 film enormously without the need to form conventional devices and opens the pathway for high-performance, low-cost, low-power consumption UV photodetector.
