Side chain engineering enhances the high-temperature resilience and ambient stability of organic synaptic transistors for neuromorphic applications. (15th December 2022)

• Record Type: Journal Article
• Authors: Zhao, Yanfei; Haseena, Sheik; Ravva, Mahesh Kumar; Zhang, Shengjie; Li, Xiang; Jiang, Jiandong; Fu, Yujun; Inal, Sahika; Wang, Qi; Wang, Yazhou; Yue, Wan; McCullocn, Iain; He, Deyan
• Is Part Of: Nano energy. Volume 104(2022)Part B
• Publication Date: 2022-12-15
• Subjects: Organic synaptic transistors -- Side chain engineering -- High-temperature resilience -- Memory retention -- Ambient stability; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2022.107985
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Organic synaptic transistors are considered to be one of the most promising device concepts for neuromorphic systems. However, repressively low memory retention and high-temperature instability greatly preclude the development and real-world application of organic synaptic transistors. Herein, we reported three conjugated polymers based on a bithiophene-thienothiophene backbone and the traditional ethylene glycol (EG) chains substituted by more hydrophobic propylene glycol (PG) and butylene glycol (BG) counterparts for three-terminal organic neuromorphic memory devices (TONMD). The resulting TONMD exhibits superior viability in ambient and high-temperature environments. BG chain-based p(b2T-TT) show ultra-long memory retention of over 10 3 s and large analog switching range (>10 ×) at 180 °C, which represents the record-high high-temperature resilience for reported TONMD to date. They also demonstrated excellent endurance of over 10 5 write-read operations and ultra-high ambient stability with 96 % of its original conductance after 3 months. Data of molecular dynamic simulations and microstructure show that the superior high-temperature resilience and ambient stability originate from more rigid conformation and stable morphology with the increased hydrophobicity of the PG and BG functionalities. Overall, rational design of oligoether side-chains will boost the device's dual high-temperature and ambient stability without compromising synaptic function and provide promising strategies for high-temperature neuromorphic applications. Graphical Abstract: Three conjugated polymers based on bithiophene-thienothiophene backbone are used for three-terminal organic synaptic transistors. Substituting traditional ethylene glycol chains by more hydrophobic propylene glycol and butylene glycol chains helps to overcome the two issues of high-temperature stability and ambient stability of the device. Through side-chain engineering strategy, organic synaptic transistors can access desirable performance metrics in high-temperature neuromorphic applications. ga1 Highlights: The effect of side chains engineering on the high temperature and ambient stability of organic synaptic transistors is reported for the first time. A record-high high-temperature resilience (180 °C) is realized in BG chain-based p(b2T-TT) devices. Excellent endurance and ultra-high ambient stability were realized in p(b2T-TT) devices. The recognition accuracy of p(b2T-TT) is the recorded high among organic synaptic transistors.