Printed thin-film transistors with functionalized single-walled carbon nanotube inks

A simple and scalable method to print high performance thin-film transistors (TFTs) with high yield by an aerosol jet printer has been developed, using water-based and chemically functionalized single-walled carbon nanotube (SCNT) inks as the semiconducting layer. The absorption spectra, Raman spectra and photoluminescence excitation (PLE) spectra of the SCNT ink indicated that metallic species and small diameter semiconducting species in CoMoCat 76 were effectively eliminated after reaction with 2,2-azobisisobutyronitrile (AIBN) in dimethyformamide (DMF). The functionalized SCNTs were dispersed in 1% SDS aqueous solution, and the as-prepared SCNTs inks were directly used to print TFTs using an aerosol jet printing system without any additional purification. Printed TFTs with high yield were obtained by tuning the concentrations of SCNTs and surfactants in the inks. The printed side-gate and bottom-gate TFTs exhibited the effective mobility of similar to 1 cm(2) V-1 s(-1) and an on/off ratio over 10(3). In addition, these printed TFTs were hysteresis-free and able to operate at low-voltage when using printable high-capacitance ion gel as the dielectric layer. The new method has opened the route to fabricate all-printed SCNT TFTs on flexible substrate with high performance.