Publication date: 9th January 2023
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 103 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 105 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.