Solution-Processed Wide-Bandgap Organic Semiconductor Nanostructures Arrays for Nonvolatile Organic Field-Effect Transistor Memory

In this paper, the development of organic field-effect transistor (OFET) memory device based on isolated and ordered nanostructures (NSs) arrays of wide-bandgap (WBG) small-molecule organic semiconductor material [2-(9-(4-(octyloxy)phenyl)-9H-fluoren-2-yl)thiophene]3 (WG(3)) is reported. The WG(3) NSs are prepared from phase separation by spin-coating blend solutions of WG(3)/trimethylolpropane (TMP), and then introduced as charge storage elements for nonvolatile OFET memory devices. Compared to the OFET memory device with smooth WG(3) film, the device based on WG(3) NSs arrays exhibits significant improvements in memory performance including larger memory window (approximate to 45 V), faster switching speed (approximate to 1 s), stable retention capability (>10(4) s), and reliable switching properties. A quantitative study of the WG(3) NSs morphology reveals that enhanced memory performance is attributed to the improved charge trapping/charge-exciton annihilation efficiency induced by increased contact area between the WG(3) NSs and pentacene layer. This versatile solution-processing approach to preparing WG(3) NSs arrays as charge trapping sites allows for fabrication of high-performance nonvolatile OFET memory devices, which could be applicable to a wide range of WBG organic semiconductor materials.