Solution‐Grown Organic Single‐Crystal Field‐Effect Transistors with Ultrahigh Response to Visible‐Blind and Deep UV Signals

Abstract

Visible‐light transparent 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT) single crystal ribbons prepared by low‐cost solution process are applied as the channel layer of the UV active field‐effect transistor. The device exhibits ultrahigh response to visible‐blind and deep UV signals because of the good charge transport ability of the C8‐BTBT single‐crystals. In the case of very weak 365 nm UV lamination (0.2 mW cm−2), the photo to dark current ratio (P) and photoresponsivity (R) reach to 3.0 × 104 and 1200 A W−1 at Vg = −23 V, Vds = −30 V. When 1 mW cm−2 280 nm deep UV light is applied, the P and R value is 8300 and 44 A W−1, respectively. The result is the highest record in the organic UV photodetectors ever reported. This work offers the possibility of fabricating a high‐performance, low‐energy exhaust UV sensor free of visible‐light interference or UV controlled memory device, and opens a practical avenue for the realization of sensitive detection of deep UV signals.