Engineering Crystalline Domain Boundaries in Organic Semiconductor Thin Films for Transistor Applications

Friday, January 24, 2014 ( 11:00 am to 12:00 pm )

Location: McLean 218A, Stevens Institute of Technology

Nancy Webb,

Dr. Stephanie Lee

New York University



EIectronics incorporating carbon-based molecules and polymers as the active material have enormous potential for emerging technologies, including disposable sensors for chemical and biological sensing, flexible displays, and light-weight solar cells for clean energy applications. Particularly promising candidates are solution-processable organic semiconductors, which can be deposited over large areas via solvent-based methods, such as inkjet printing or spin coating. While great strides have been made towards realizing high-performance solution-processed organic electronics, a major challenge still facing the organic electronics community is developing a fundamental understanding of how the morphology of these organic semiconductor thin films impacts overall device performance. My talk will focus on elucidating the relationship between the structure of spherulites and charge transport through the active layer of organic thin-film transistors (OTFTs) comprising these crystalline superstructures. Specifically, I will highlight my research on controlling the nucleation density and crystallization direction of spherulites in triethylsilylethynyl anthradithiophene (TES ADT) thin films in order to engineer the density and type of crystalline boundaries. Using a combination of conductive atomic force microscopy, transistor testing and four-probe measurements to study charge transport, I will quantify how these boundaries affect charge transport in these films. 




Stephanie Lee is currently a postdoctoral fellow through the Postdoctoral and Transition Program for Academic Diversity in the Department of Chemistry at New York University. Her current research, under the advisement of Professor Michael D. Ward in the Molecular Design Institute, involves using colloidal particles as molecular mimics to explore fundamental nucleation and crystallization processes in organic crystals, as well as directing molecular assembly in organic films via hydrogen-bonded frameworks. As a postdoctoral fellow, Stephanie has also had the opportunity to teach Thermodynamics and Kinetics for chemistry majors and Energy and the Environment for non-science majors through the chemistry department at NYU.  Prior to her postdoctoral appointment, Stephanie earned her B.S. in Chemical Engineering from MIT in 2007 and Ph.D. in Chemical Engineering and Materials Science in 2012 from Princeton University. Under the advisement of Professor Lynn Loo, her graduate work focused on developing processing methods to engineer the structure of solution-processed organic semiconductor thin films in order to examine how morphology influences device performance in organic thin-film transistors. She also collaborated on several projects exploring the morphology of two-component organic semiconductor systems for photovoltaic applications.