Fully Printed and Encapsulated SWCNT-Based Thin Film Transistors via a Combination of R2R Gravure and Inkjet Printing

  • Christa M. Homenick
  • , Robert James
  • , Gregory P. Lopinski
  • , Jeffrey Dunford
  • , Junfeng Sun
  • , Hyejin Park
  • , Younsu Jung
  • , Gyoujin Cho
  • , Patrick R.L. Malenfant

Research output: Contribution to journalArticlepeer-review

136 Scopus citations

Abstract

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/SiO2 in which an ink consisting of 6:1 PFDD:SWCNT ratio with 50 mg L-1 SWCNT concentration printed at a drop spacing of 20 μm results in TFTs with mobilities of ∼25 cm2 V-1 s-1 and 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 cm2 V-1 s-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 cm2 V-1 s-1 with 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.

Original languageEnglish
Pages (from-to)27900-27910
Number of pages11
JournalACS Applied Materials and Interfaces
Volume8
Issue number41
DOIs
StatePublished - 19 Oct 2016
Externally publishedYes

Keywords

  • enriched semiconducting carbon nanotube ink
  • fully printed
  • roll-to-roll
  • SWCNT ink formulation
  • thin film transistor

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