Chemistry Seminar: "Twisted Organic Semiconductor Crystals"

Please join the chemistry department for a seminar from Stephanie Lee, Associate Professor of Chemistry at New York University (NYU). Refreshments will be provided.

Seminar Title: "Twisted Organic Semiconductor Crystals"

Research Abstract: Molecular crystals that twist as they grow introduce completely unexplored features to materials design. Here, we present growth-induced twists to molecular semiconductor crystals with the expectation that continually precessing crystallographic orientations can modulate interactions with photons and electrons. We have found that a variety of organic semiconductors and charge transfer complexes can be readily induced to grow from the melt as spherulites of tightly packed helicoidal fibrils. Because twisting exposes different crystallographic faces at the film/air interface, all crystal orientation-dependent properties, including absorptivity, emissivity, conductivity, solubility and reactivity, are patterned in the films. Twisting also imparts chirality to crystals, opening the possibility of repurposing centrosymmetric molecules for chiroptoelectronics.

Speaker Biography: Stephanie Lee joined the Department of Chemistry at New York University as an associate professor in January 2021. She received a BS in chemical engineering from MIT in 2007 and a PhD in chemical engineering and materials science from Princeton University in 2012. She was a Provost’s Postdoctoral Fellow in the Molecular Design Institute at NYU from 2012-2014 before joining Stevens Institute of Technology as an assistant professor. Her research group studies the crystal engineering of solution-processable semiconductors for emerging optoelectronic applications, including flexible displays and photovoltaics. Their strategies involve the use of solution rheology to monitor and control semiconducting polymer network formation, scaffold-directed crystallization of small molecules into vertical crystal arrays and nanoconfined crystallization to shift the thermodynamics and stability of metal-halide perovskites for high performance solar cells. Lee is a recipient of the Stevens Early Career Award for Research Excellence and a 2019 NSF CAREER awardee.

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