Nano@Tech Fall 2023 Series | Narrow Bandgap Conjugated Polymers with Strong Correlations and Open-Shell Electronic Structures: Towards New Phenomena and Emergent Technologies

Featuring Jason Azoulay, associate professor and Vasser-Woolley GRA Distinguished Investigator in Sensors and Instrumentation in the School of Chemistry and Biochemistry at Georgia Tech.

Abstract: For over forty years, conjugated polymers (CPs) have been a source of enormous fundamental breakthroughs, enabling foundational insight into the nature of π-bonding and electron pairing, the creation of novel optoelectronic functionalities, and the development of commercially relevant technologies. Despite the achievement of significant technological milestones, the complex structural and energetic heterogeneities that define these materials preclude bandgap control at low energies, tailored interactions with infrared (IR) light, the study of fundamental physical phenomena, and the design and realization of new device functionalities. To address these modern challenges, we have developed precision synthetic methods that provide control of the frontier orbital energetics, coplanarity of the conjugated backbone, intermolecular interactions, and many chemical, electronic, and structural features that affect electronic coherence within these π-conjugated macromolecules, enabling unprecedented levels of bandgap control. The utility of these materials for understanding emergent light-matter interactions that enable the transduction of IR photons and the extension of CPs into high-performance IR optoelectronics will be discussed. We subsequently discovered that narrow bandgaps afforded through extended π-conjugation are intimately related to the coexistence of nearly degenerate electronic states. Through articulating novel mechanisms of spin alignment, topology control, and exchange, we have enabled the synthesis of neutral CPs with ground states that span the entire range from “conventional” closed-shell structures to biradicaloids with varying degrees of open-shell character, to diradicals in both singlet (S = 0) and triplet (S = 1) spin-states. These materials exhibit weaker intramolecular electron-electron pairing and stronger electronic correlations than their closed-shell counterparts, which imparts novel optical, transient, transport, thermal, spin, magnetic, quantum, and coherent phenomena not previously measured in soft-matter (polymer) systems. These novel attributes have enabled new optoelectronic and device functionalities that cannot be realized with current semiconductor technologies and provide a remarkable platform to study new phenomena at the interface of various fields such as chemistry, condensed matter physics, and quantum matter.

Bio: Jason Azoulay is an associate professor in the Schools of Chemistry and Biochemistry and Materials Science and Engineering at the Georgia Institute of Technology. He is the Georgia Research Alliance Vasser-Woolley Distinguished Investigator in Optoelectronics and co-director of the Center for Organic Photonics and Electronics. Prior to joining Georgia Tech, he was an associate professor of polymer science and engineering at The University of Southern Mississippi. He received his Ph.D. in chemistry from the University of California Santa Barbara and performed post-doctoral studies at Sandia National Laboratories. Azoulay’s research group unites strong synthetic foundations with physics, materials science, and engineering to synthesize and apply next-generation functional materials. Research efforts within the group encompass homogeneous catalysis applied to polymer synthesis; electronic, photonic, magnetic, and quantum materials; device fabrication and engineering; chemical sensing in complex aqueous environments for environmental monitoring; and the synthesis, application, and engineering of high-performance polymers across multiple technology platforms. Azoulay has directed large interdisciplinary and center-level efforts in conjugated polymers, optoelectronics, and chemical sensing. He has also received numerous awards and honors, including the 2017 Nokia-Bell Labs Prize and Department of Energy Early Career Research Program Award.

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A boxed lunch will be served on a first come, first served basis.