This Small Business Innovation Research (SBIR) Phase I project aims to develop a diameter refined semiconducting single walled carbon nanotubes (SWCNTs) to address the challenge of bandgap heterogeneity in semiconducting SWNTs. The plan is to utilize the latest advances in SWNT separation including Density Gradient Ultracentrifugation (DGU), preferential chemistry, and chromatographic techniques to reach the desired outcome of uniform bandgap, semiconducting SWNTs. The high degree of uniformity of this refined material will provide superior device performance (threshold voltage uniformity, sub-threshold swing, on/off ratio) in Thin Film Transistors (TFTs) for the next generation of displays based on Organic Light-Emitting Diodes (OLEDs). The broader/commercial impact of this project will be the potential to provide high mobility, solution processable semiconductors to enable low-cost, large-scale OLED production. Currently, the display industry is attempting to develop economical, large-area displays based on OLED devices. Unlike current liquid crystal displays (LCDs), OLEDs are current-driven devices and require semiconductor mobilities that are well above the performance threshold of the amorphous silicon TFTs currently used in LCDs. In addition, the display industry is planning to shift from expensive vacuum processes (sputtering, chemical vapor deposition) toward solution processes (spin-coating, printing) which also have the potential for continuous, high-volume manufacturing. Diameter refined semiconducting carbon nanotubes are not only solution processable, but also have the potential to overcome mobility limitations that other material classes such as organic semiconductors and amorphous oxides have.
