Highly Stretchable Carbon Nanotube Transistors with Ion Gel Gate Dielectrics

Abstract

Field-effect transistors (FETs) that are stretchable up to 50% without appreciable degradation in performance are demonstrated. The FETs are based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes (CNTs) as the channel, a flexible ion gel as the dielectric, and buckled metal films as electrodes. The buckling of the CNT film enables the high degree of stretchability while the flexible nature of the ion gel allows it to maintain a high quality interface with the CNTs during stretching. An excellent on/off ratio of >10(4), a field-effect mobility of 10 cm(2) · V(-1) · s(-1), and a low operating voltage of <2 V are achieved over repeated mechanical cycling, with further strain accommodation possible. Deformable FETs are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins.

Highly stretchable carbon nanotube transistors enabled by buckled ion gel gate dielectrics

“…[17][18][19][20] The high double layer capacitance of ion gels also allows FETs to operate at low gate biases of less than 2 V. Our previous nanotube FETs incorporating unbuckled ion gel dielectrics were stretchable up to 50% without appreciable degradation in performance before fracture of the ion gel film. 16 Here, we show that by buckling the ion gel, the integrity and performance of the FETs are extended to nearly 90% elongation, limited only by the degree of pre-strain that can be accommodated by the elastomeric substrate during fabrication. The FETs maintain an on/off ratio of >10 4 and a field-effect mobility of 5 cm 2 V À1 s À1 under elongation and demonstrate invariant performance over 1000 stretching cycles.…”

“…15 We previously demonstrated stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric. 16 Ion gels are attractive for stretchable FETs because of their excellent ionic conductivity, high specific capacitance, printability, and flexibility. [17][18][19][20] The high double layer capacitance of ion gels also allows FETs to operate at low gate biases of less than 2 V. Our previous nanotube FETs incorporating unbuckled ion gel dielectrics were stretchable up to 50% without appreciable degradation in performance before fracture of the ion gel film.…”

“…The procedures used to prepare the polymer wrapped carbon nanotubes and ion gels and to electrically characterize the FETs are similar to those used in our previous report 16 and are described in detail in the supplementary material. 21 Figure 1(a) depicts the new FET fabrication approach.…”

Ultrastretchable Fiber Sensor with High Sensitivity in Whole Workable Range for Wearable Electronics and Implantable Medicine

“…Buckled structures are usually used to fabricate stretchable conductors with stable conductance during deformation, in which conducting thin layers are deposited on the surface of a prestretched substrate followed by stretch‐release 18, 19, 20. Here, we report a novel buckled sheath–core fiber‐based ultrastretchable strain sensor and demonstrate its outstanding sensing performance in whole workable range.…”

Biomimicking Topographic Elastomeric Petals (E‐Petals) for Omnidirectional Stretchable and Printable Electronics

“…The booming of research in ultraflexible, stretchable, and wearable electronics in the past decade has witnessed the remarkable development of advanced materials,1, 2, 3 structures,4, 5, 6, 7, 8, 9 and devices10, 11, 12, 13, 14, 15, 16, 17, 18, 19 that can function under large tensile strains (1%). In particular, the realization of highly conductive and stretchable metal interconnects, contacts, and electrodes are recognized as one critical milestone for these thin film devices 2, 13, 20, 21, 22, 23, 24.…”