Ultrasoft and High-Adhesion Block Copolymers for Neuromorphic Computing

• Published in: ACS applied materials & interfaces Vol. 16; no. 10; pp. 12897 - 12906
• Main Authors: Li, Xiaohong, Ou, Xingcheng, Chen, Guoliang, Bi, Ran, Li, Ziqian, Xie, Zhuang, Yue, Wan, Guo, Shuang-Zhuang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 13.03.2024
• Subjects: adhesion; air; composite polymers; digital database; memory; modulus of elasticity; Organic Electronic Devices; plasticity; synapse; transistors; block copolymer; artificial synapse; organic conjugated polymers; poly(dimethylsiloxane); organic synaptic transistor; polyisoindigo-bithiophene
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.3c19350

The “von Neumann bottleneck” is a formidable challenge in conventional computing, driving exploration into artificial synapses. Organic semiconductor materials show promise but are hindered by issues such as poor adhesion and a high elastic modulus. Here, we combine polyisoindigo-bithiophene (PIID-2T) with grafted poly­(dimethylsiloxane) (PDMS) to synthesize the triblock-conjugated polymer (PIID-2T-PDMS). The polymer exhibited substantial enhancements in adhesion (4.8–68.8 nN) and reductions in elastic modulus (1.6–0.58 GPa) while maintaining the electrical characteristics of PIID-2T. The three-terminal organic synaptic transistor (three-terminal p-type organic artificial synapse (TPOAS)), constructed using PIID-2T-PDMS, exhibits an unprecedented analog switching range of 276×, surpassing previous records, and a remarkable memory on–off ratio of 106. Moreover, the device displays outstanding operational stability, retaining 99.6% of its original current after 1600 write–read events in the air. Notably, TPOAS replicates key biological synaptic behaviors, including paired-pulse facilitation (PPF), short-term plasticity (STP), and long-term plasticity (LTP). Simulations using handwritten digital data sets reveal an impressive recognition accuracy of 91.7%. This study presents a polyisoindigo-bithiophene-based block copolymer that offers enhanced adhesion, reduced elastic modulus, and high-performance artificial synapses, paving the way for the next generation of neuromorphic computing systems.