Choi, Kwang-Hun Im, Seongil Plant, Aaron Neri Soto, Carlos Lee, Hanna Choi, Changsoon Jang, Ho Won Cho, Jeong Ho Ju, Hyunsu Lee, Youngmin Lim, Jung Ah 2025-09-17T02:02:54Z 2025-09-17T02:02:54Z 2025-09-16 2025-11 0935-9648 https://pubs.kist.re.kr/handle/201004/153173 Growing interest in organic electrochemical synaptic transistors (OECT-STrs) based on conjugated polymer mixed ionic-electronic conductors (CP-MIECs) has intensified, leading to the need to establish clear design rules and fundamentally understand the distinct roles of crystalline and amorphous domains in the electrochemical doping behavior of CP-MIEC films. Here, OECT-STrs based on regioregular-block-regiorandom (regioblock) conjugated copolymers with precisely controlled crystallinity are demonstrated. The crystallinity of a poly(3-hexylthiophene) regioblock copolymer is systematically tuned by varying the fraction of regiorandom blocks without altering the geometry or orientation of the crystalline phase. It is shown that incorporating an amorphous phase into the active channel of OECT-STrs significantly enhances the neuromorphic learning efficiency by improving modulation uniformity. This improvement results from sequential polaron formation in the amorphous regions and bipolaron formation in the crystalline domains during potentiation. Additionally, crystalline phases provide better state retention at low potentiation states, while amorphous phases contribute to improved long-term retention at high potentiation states by enhancing charge carrier localization through stronger Coulombic interactions. Neural network simulations based on actual device conductance demonstrate that OECT-STrs with a high amorphous fraction consume only 18% of the power required by devices with a highly crystalline film, owing to the need for fewer repetitive learning cycles. English WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Role of Amorphous Phases in Mixed Conduction of Conjugated Regioblock Copolymers for Organic Electrochemical Synaptic Transistors Article 10.1002/adma.202502133 1 Advanced Materials, v.37, no.45 Advanced Materials 37 45 Y scie scopus 001560400900001 2-s2.0-105014610841 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article PERFORMANCE ELECTRONICS TRANSPORT artificial synaptic transistor crystallinity dependent redox properties neuromorphic devices organic electrochemical electronics organic mixed ionic-electronic conductors regioblock copolymer conjugated polymer