Jianying Ouyang

Title : Enrichment of sc SWCNTs for thin film transistor and gas sensing applications

Abstract:

In this oral presentation, purification and enrichment of semiconducting single-walled carbon nanotubes (sc-SWCNTs) will be reported and discussed. Conjugated polymer extraction (CPE) process was developed and it was found that a trace amount of polar solvents was able to boost the enrichment yield drastically. We provide insights on CPE by demonstrating that a conjugated polymer having a hydrophobic backbone and hydrophilic side chains provides near full recovery (95%) of sc-SWCNTs using a multi-extraction protocol. This polymer, poly(9,9-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene-alt-pyridine-2,5) [P(FEt₃M-Py-2,5)] was designed and synthesized in our laboratories. The resulting hydrophilic SWCNT dispersions demonstrate long-term colloidal stability, making them suitable for ink formulation and high-performance thin-film transistors (TFT) fabrication. As a result, the enriched sc-SWCNTs demonstrated application in high-performance fully ink-jet printed TFT [ACS Nano 2018, 12, 2, 1910–1919]. We also developed a novel indigo-fluorene-based copolymer (PFIDBoc) that has been designed to selectively enrich sc-SWCNTs with excellent purity (>99.9%) yet contain a latent function in the form of a tert-butoxy (t-BOC)-protected amine that can be later revealed and exploited for carbon dioxide gas sensing. The enriched sc-SWCNTs demonstrated TFT-based CO₂ gas sensing application with up to ∼5.4% sensitivity between 400 and 2000 ppm in air with a relative humidity of ∼ 40% [ACS Sensors 2020, 5, 2136-2145].

Biography:

Dr. Jianying Ouyang graduated from National University of Singapore in 2003 with a PhD degree in Polymer Chemistry. She continued her research in City University of New York from 2003-2004. In 2005, she joined National Research Council Canada in Ottawa as a visiting fellow, dedicating to synthesis and characterization of semiconducting nanocrystals (quantum dots). In 2008, she was hired as a research officer and continued her research in quantum dots aiming for photovoltaics, bio-imaging, and photodetectors. In recent years, she also dedicated to purification and enrichment of single walled carbon nanotubes used for thin film transistors and gas sensors. She has published ca. 50 research articles in SCI journals.