NanoIntegris - Model IsoSol-S100 -Polymer-Wrapped Nanotubes

Experimentally, thin film transistors have been prepared from the IsoSol-S100 material on SiO₂/Si substrates⁷, leading to average mobilities exceeding 27cm²/(Vs) and On/Off ratios of 1.8×10⁶. These properties allow the material to be well-suited for ink jet and aerosol jet printing. Haitian Chen from USC says: “Our research group has been able to obtain excellent electrical properties, more specifically mobility of 25 cm2V-1s-1 and current on/off ratio of 4 x 10^6 from thin film transistors (TFTs) based on Nanointegris 99.9% semiconducting carbon nanotube (CNT) solution (IsoSol-S100). It is an outstanding material for the development of CNT-based macroelectronics and flexible macroelectronics. ”

UV-Vis-NIR spectrophotometric assessment of purity² indicate that this material has semiconducting purities at or greater than 99.9% with the metrics of Itkis Ratio³ and Phi Values⁴exceeding 0.5 and 0.4, respectively.

The highly graphitized starting material and low sonication intensity utilized for the extraction technique minimizes damage to the nanotubes, allowing the material to exhibit high crysallinity and longer average lengths of 1-2µm, not previously seen when utilizing DGU⁵ or Chromatography-based⁶ separation methods.

Additionally, the material is processed in organic solvent with a polymer : nanotube ratio that can be adjusted to less than a factor of four (surfactant : nanotube ratio is 1×10³ in our aqueous surfactant solutions). The solutions also display stabilities of greater than six months. These properties promote great nanotube deposition and adhesion for device creation.

• _{Optical Purity : >99.9%}
• _{Itkis Ratio (?) : >0.5}
• _{Phi Value (Φ) : >0.39}
• _{Nanotube Concentration : >0.01mg/mL}
• _{Surfactant : Nanotube Concentration : <4}
• _{Standard Solvent Media : Toluene}
• _{Shelf Life : 3-6 months}

The IsoSol-S100 product has been a featured material within numerous research efforts. The primary usage for the IsoSol-S100 material is for the creation of thin film transistors. What makes this material extremely appealing is that its usage enables the creation of thin film transistors that are fully printed, high-performing, flexible, stable, scalable, and low cost, with the capacity to span large areas.

At the University of Southern California, an active-matrix electrochromic display was created utilizing NanoIntegris’ IsoSol-S100 material. [1] The SWCNT thin film transistors had channel lengths of ~105 um and channel widths of ~1000 µm. The TFT exhibited an on-state current density of 3.62 µA/mm at source drain voltage (V_DS)= -1V and gate voltage (VG) = -15V with an average on-off ratio of 10⁴. The average mobility was ~3.92 cm²/Vs. These results from the fully screen-printed TFT array were comparable wth Javey and Cho’s work on gravure printed CNT TFT’s [2] and backplanes [3,4] and showed the potential to enable new applications such as monolithically integrated active-matrix organic light-emitting diodes (AMOLED) and backplanes desirable for practical applications such as large-area active matrix-based flexible displays and sensing systems.

1. ACS Nano 2016, 10, 9816-9822.
2. Nano Lett. 2013, 13, 3864-9.
3. Adv. Mater. 2015, 27, 1561.
4. Adv. Mater. 2002, 14, 1460

NanoIntegris’ IsoSol-S100 material was ink-jet printed at 93 mg/L onto silicon test chips using <20µm drop spacing. The transistors had dense uniform network spanning the source and drain with an average hole mobilities of ~30 cm²/Vs, and on-state current densities greater than 0.75 mA/mm, with on/off ratios of 10⁶.

Transistors were generated on flexible polyethylene terephthalate (PET) substrate with silver gate electrodes and high-k BaTiO³ dilelectric layers, printed via a R2R gravure printing process. The IsoSol-S100 was inkjet printed at 50 mg/L along with silver source/ drain contacts, defining a channel of 1000 µm x 150 µm. The on/off ratios were determined to be 7×10⁴ with a subthreshold swing of 1.8V/decade, a transconductance of 0.26 µS/V, a threshold voltage of -2.5V, a calculated capacitance of 6.5 nF/cm², and a mobility of 6cm²/Vs.

[1] ACS Appl. Mater. Interfaces 2016, 8, 27900-27910.