Fully Printed and Encapsulated SWCNT-Based Thin Film Transistors via a Combination of R2R Gravure and Inkjet Printing.
Fully printed thin film transistors (TFT) based on poly(9,9-di-n-dodecylfluorene) (PFDD) wrapped semiconducting single walled carbon nanotube (SWCNT) channels are fabricated by a practical route that combines roll-to-roll (R2R) gravure and ink jet printing. SWCNT network density is easily controlled via ink formulation (concentration and polymer:CNT ratio) and jetting conditions (droplet size, drop spacing, and number of printed layers). Optimum inkjet printing conditions are established on Si/SiO2in which an ink consisting of 6:1 PFDD:SWCNT ratio with 50 mg L-1SWCNT concentration printed at a drop spacing of 20 μm results in TFTs with mobilities of ∼25 cm2V-1s-1and on-/off-current ratios > 105. These conditions yield excellent network uniformity and are used in a fully additive process to fabricate fully printed TFTs on PET substrates with mobility values > 5 cm2V-1s-1(R2R printed gate electrode and dielectric; inkjet printed channel and source/drain electrodes). An inkjet printed encapsulation layer completes the TFT process (fabricated in bottom gate, top contact TFT configuration) and provides mobilities > 1 cm2V-1s-1with good operational stability, based on the performance of an inverter circuit. An array of 20 TFTs shows that most have less than 10% variability in terms of threshold voltage, transconductance, on-current, and subthreshold swing.
National Research Council Canada , 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada.
Christa M
CM
Homenick
RF Technologies Ottawa, Communications Research Centre Canada , Nepean, Ontario K2H 8S2, Canada.
Robert
R
James
National Research Council Canada , 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada.
Gregory P
GP
Lopinski
National Research Council Canada M-50 , 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
Jeffrey
J
Dunford
Department of Printed Electronics Engineering, Sunchon National University Suncheon , Jeonnam 540-742, Republic of Korea.
Junfeng
J
Sun
Department of Printed Electronics Engineering, Sunchon National University Suncheon , Jeonnam 540-742, Republic of Korea.
Hyejin
H
Park
Department of Printed Electronics Engineering, Sunchon National University Suncheon , Jeonnam 540-742, Republic of Korea.
Younsu
Y
Jung
Department of Printed Electronics Engineering, Sunchon National University Suncheon , Jeonnam 540-742, Republic of Korea.
Gyoujin
G
Cho
National Research Council Canada M-50 , 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
Patrick R L
PRL
Malenfant
SWCNT ink formulation; enriched semiconducting carbon nanotube ink; fully printed; roll-to-roll; thin film transistor