Performance Study of Flexible Solar-blind Ultraviolet Photodetector

In recent years, solar-blind ultraviolet (UV) photodetectors have attracted more and more attention due to the strong resistance to background radiation interference and high detection sensitivity. However, most photodetectors are based on rigid substrates, which cannot be bent and folded. Flexible photodetectors have the advantages of being able to fit on surfaces of different shapes, which can reduce production costs and device volume. Meanwhile, carbon dots (CDs) have drawn great attention because of its high carrier mobility and excellent optoelectronic properties. The CDs solution was prepared by electrochemical method, which was uniformly distributed, with an average diameter of 2.5 nm and strong light absorption around 230 nm. The vertical structure is more advantageous than the previous horizontal structure. Since the channel length is determined by the thickness of the absorbing layer, it can be processed to the nanometer scale by spin-coating method, which is beneficial to improve the field-effect mobility and increase the leakage current. In this paper, a vertical structured flexible solar blind UV photodetector based on CD is introduced, which can reach more than 90% of the original current in the bending strain range of 0%-0.6%.