Printable carbon nanotube-based elastic conductors for fully-printed sub-1 V stretchable electrolyte-gated transistors and inverters

Single-walled carbon nanotube (SWCNT)-based hybrid gel electrodes were fabricated for fully printed stretchable thin-film transistors and inverters operating at very small voltages (below 1 V). Printable and stretchable electrodes were fabricated by supplementing electrically conductive SWCNTs in rubbery polymer electrolytes, known as ionic gels. To fabricate stretchable electronic circuits, SWCNT-based stretchable source and drain electrodes as well as semiconductors, gate dielectrics, gate electrodes (either conducting polymer or SWCNT-based hybrid electrode) and load resistors were directly deposited by spray printing at low temperatures (<= 130 degrees C). Fully printed electrolyte-gated transistors (EGTs) based on SWCNT hybrid electrodes turned on and off at low operation voltages below 1 V and the devices showed low hysteresis with reasonably high on/off current ratios on polymer and paper substrates. In addition, stretchable side-gated coplanar transistors were successfully demonstrated on a rubber substrate, which exhibited reliable electrical characteristics even at a strain of 100%. An array of resistor-loaded stretchable inverters was also fabricated by spray-printing EGTs and CNT-based resistors. The resulting inverters exhibited appropriate voltage-inverting characteristics at different tensile strains and the shift in inversion voltage was in a very small Vin range of 0.1 V. These results demonstrate that the hybrid gel-type electrodes are promising for the fabrication of low-voltage stretchable all-printed transistors and electronic circuits.