A full transparent high-performance flexible phototransistor with an ultra-short channel length

Abstract

Ultraviolet (UV) photodetectors (PDs), which can convert ultraviolet light into electrical signals for dynamic monitoring, have attracted tremendous attention to protect humans from diseases induced by harmful light radiations. However, there are numerous challenges, such as unsatisfied transparency, poor mechanical flexibility and low photoelectric efficiency, in the development of superior PDs, which has hindered the further development of PDs. In this study, a full transparent vertical phototransistor by sandwiching indium tin oxide (ITO) between a single-walled carbon nanotube (SWCNT) source and drain electrode is invented for high-performance transparent UV photodetectors. Moreover, benefited from the nano-scale transmission channels in the vertical direction and rational selection of materials, the photodetector exhibits superior photoelectric performance, particularly in extremely high photoresponsivity of up to 1.02 × 10⁴ A W⁻¹ and photosensitivity above 4.2 × 10⁵%. Our transparent photodetector is competitive and superior to other reported planar TFTs or two-terminals devices. Moreover, the photodetectors maintain transparency of over 85% and high detectivity of up to 1.73 × 10¹⁶ Jones under a 15 mm bending, which ensures outstanding mechanical robustness against mechanical bending. This study establishes a new approach for high-performance transparent flexible UV photodetectors and shows great potential for next-generation “see-through” electronic devices.