A Bendable, Stretchable Transistor with Aligned Carbon Nanotube Films

Controlling the packing density and degree of alignment of carbon nanotubes is essential for obtaining optimal charge transport properties in carbon nanotube transistors. Here, a method is introduced for evaporative self-assembly at the air-water interface to deposit continuous films of well-aligned, uniform semiconducting bundle nanotubes for stretchable and bendable transistor applications. Polymer-wrapped nanotubes in organic ink are dropped on the water surface and diffused at the air-water interface to deposit aligned semiconducting single-walled carbon nanotubes on a partially submersed substrate. The speed dependency of the substrate is also elucidated. The optimized conditions enable alignment within +/- 5 degrees at a packing density of approximate to 12.5 nanotubes mu m(-1) with continuously well-ordered layers. The semiconducting single-walled carbon nanotube films enabled a high degree of stretchability, with the flexible nature of the ion gel maintaining the charge properties of the device. The resulting ion-gel-based field effect transistor devices have a high mobility of 5.11 cm(2) V-1 s(-1) and an on/off ratio >10(4) under both bending and elongation and demonstrate a continuous performance over 1000 stretching cycles.