KES5-1643
Manipulating Polarons in Organic Semiconductors: From Molecular Structure to Device Function
When and Where
Sep 30, 2026
11:10 - 11:35
Presenter(s)
Ji Seon KIM (Oxford University)
Co-Author(s)
Abstract
Polarons, formed through strong electron-phonon coupling between charge carriers and molecular vibrations, play a central role in determining the performance of organic semiconductors. They govern charge generation, transport, recombination, and ion-electron interactions, yet the molecular mechanisms controlling their formation, transport, and dynamics remain poorly understood. In this talk, I will present our recent studies demonstrating how molecular structure can be used to manipulate polaron formation, transport, and dynamics across a broad range of organic electronic devices. First, I will show how molecular structure including molecular electrostatic interactions controls charge generation, structure relaxation, and photostability in organic photovoltaics and photodetectors [1-4]. I will then demonstrate how subtle variations in side-chain nature and side-chain density regulate polaron formation and transport through electron-phonon coupling during electrochemical doping [5]. Finally, I will present in situ spectroscopic studies of organic electrochemical and synaptic transistors, revealing how molecular structure governs ion-induced polaron formation, transport, and ion retention during device operation [6]. These findings establish molecular design principles for manipulating polarons to control device function, providing new strategies for the development of high-performance organic electronic devices.
[1] Fu et al., “Molecular orientation-dependent energetic shifts in solution processed non-fullerene acceptors and their impact on organic solar cell performance”, NATURE COMMUNICATIONS, (2023) 14, 1870, doi:10.1038/s41467-023-37234-0
[2] Rana et al, “Octupole Moment Driven Free Charge Generation in Partially Chlorinated Subphthalocyanine for Planar Heterojunction Organic Photodetectors”, NATURE COMMUNICATIONS, (2024) 15(1), 5058. doi:10.1038/s41467-024-49169-1
[3] Luke et al., “Key molecular perspectives for high stability in organic photovoltaics”, NATURE REVIEWS MATERIALS (2003), doi:10.1038/s41578-023-00606-5
[4] Pagano et al., “Slow vibrational relaxation drives ultrafast formation of photoexcited polaron pair states in glycolated conjugated polymers”. NATURE COMMUNICATIONS, (2024), 15(1), 6153. doi:10.1038/s41467-024-50530-7
[5] Stewart, K. et al., “Understanding Effects of Alkyl Side Chain Density on Polaron Formation via Electrochemical Doping in Thiophene Polymers”, Advanced Materials (2024) 36(20). doi:10.1002/adma.202211184
[6] Stewart, K., et al., “Polarons in DPP Polymers - How Glycol Side Chains and Elongated Conjugated Backbone Influence the Formation and Transport.” Advanced Electronic Materials (2026) 12(7). doi:10.1002/aelm.202500731
[1] Fu et al., “Molecular orientation-dependent energetic shifts in solution processed non-fullerene acceptors and their impact on organic solar cell performance”, NATURE COMMUNICATIONS, (2023) 14, 1870, doi:10.1038/s41467-023-37234-0
[2] Rana et al, “Octupole Moment Driven Free Charge Generation in Partially Chlorinated Subphthalocyanine for Planar Heterojunction Organic Photodetectors”, NATURE COMMUNICATIONS, (2024) 15(1), 5058. doi:10.1038/s41467-024-49169-1
[3] Luke et al., “Key molecular perspectives for high stability in organic photovoltaics”, NATURE REVIEWS MATERIALS (2003), doi:10.1038/s41578-023-00606-5
[4] Pagano et al., “Slow vibrational relaxation drives ultrafast formation of photoexcited polaron pair states in glycolated conjugated polymers”. NATURE COMMUNICATIONS, (2024), 15(1), 6153. doi:10.1038/s41467-024-50530-7
[5] Stewart, K. et al., “Understanding Effects of Alkyl Side Chain Density on Polaron Formation via Electrochemical Doping in Thiophene Polymers”, Advanced Materials (2024) 36(20). doi:10.1002/adma.202211184
[6] Stewart, K., et al., “Polarons in DPP Polymers - How Glycol Side Chains and Elongated Conjugated Backbone Influence the Formation and Transport.” Advanced Electronic Materials (2026) 12(7). doi:10.1002/aelm.202500731
