POS5-0827
Systematic Development of Open-Shell Quinoid-Proquinoid Copolymers by Balancing Crystallinity and Spin Properties for Efficient Spin Transport
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Younghyo Kim (Advanced Photonics Research Institute (APRI), Gwangju Institute of Science and Technology (GIST))
Co-Author(s)
Abstract
Beyond conventional charge transport, organic conjugated polymers have recently expanded their scope to spin transport for advanced information technologies. In particular, open-shell quinoidal polymers are highly promising due to their intrinsic spins and extended conjugation; however, most studies remain limited to the simple reporting of new materials, leaving structure-spin transport relationships poorly understood. To explore this relationship, it is essential to precisely control their chemical structures and integrate them into practical spintronic devices.
Here, we report a series of copolymers, Q-PQ-0, Q-PQ-0.2, and Q-PQ-0.5, synthesized by precisely controlling the ratio of quinoid (Q) and pro-quinoid (PQ) open-shell moieties. Electron paramagnetic resonance (EPR) analysis reveals the most prominent spin properties in Q-PQ-0.5 among the series, which is attributed to the enhanced spin-orbit coupling and stabilized triplet state induced by the heteroatom-rich, conjugation-extended PQ unit. However, the macroscopic magnetic and transport properties were predominantly governed by structural ordering rather than spin density alone. With an optimal structural balance, Q-PQ-0.2 achieved the highest crystallinity, thereby demonstrating a superior electron mobility (4.60×10-2 cm2 V-1 s-1) and robust long-range spin alignment with a remanent magnetization (Mr) of 0.22 memu g-1 and a coercivity (Hc) of 89.29 Oe. In contrast, the disordered morphology of Q-PQ-0.5 hindered both charge transport and spin alignment. Consequently, these distinct polymeric characteristics are expected to yield significant differences in magnetoresistance (MR) responses within spintronic devices. This study demonstrates that synergistic control over crystallinity and spin properties serves as a key to achieving high-performance organic spintronics.
Here, we report a series of copolymers, Q-PQ-0, Q-PQ-0.2, and Q-PQ-0.5, synthesized by precisely controlling the ratio of quinoid (Q) and pro-quinoid (PQ) open-shell moieties. Electron paramagnetic resonance (EPR) analysis reveals the most prominent spin properties in Q-PQ-0.5 among the series, which is attributed to the enhanced spin-orbit coupling and stabilized triplet state induced by the heteroatom-rich, conjugation-extended PQ unit. However, the macroscopic magnetic and transport properties were predominantly governed by structural ordering rather than spin density alone. With an optimal structural balance, Q-PQ-0.2 achieved the highest crystallinity, thereby demonstrating a superior electron mobility (4.60×10-2 cm2 V-1 s-1) and robust long-range spin alignment with a remanent magnetization (Mr) of 0.22 memu g-1 and a coercivity (Hc) of 89.29 Oe. In contrast, the disordered morphology of Q-PQ-0.5 hindered both charge transport and spin alignment. Consequently, these distinct polymeric characteristics are expected to yield significant differences in magnetoresistance (MR) responses within spintronic devices. This study demonstrates that synergistic control over crystallinity and spin properties serves as a key to achieving high-performance organic spintronics.
