An antifatigue and self-healable ionic polyurethane/ionic liquid composite as the channel layer for a low energy cost synaptic transistor

Abstract

The developing trends of the traditional transistor include being synaptic and flexible, which could down low the energy cost and realize the daily application of flexible electronics, respectively. However, only bendable synaptic transistor has been developed, which is mainly restricted by the rigid components. Among which, the channel layer has not been replaced by any stretchable material yet. In this work, we synthesized an ionic polyurethane (iPU), and blend it with ionic liquid (IL) to construct a flexible channel layer with high transparency, stability, antifatigue and stretchability. The self-healing process can be completed at ambient and operating temperatures, and the self-healing speed was accelerated by the elevated temperature. The recovery ratio of the iPU/IL film was 95% after cyclic stretch to 50% strain for 100 cycles, which proved good antifatigue property. The stable combination between iPU and IL was verified by the two-dimensional Raman spectra, and the interconnected paths of IL around hard domains were discovered, which was probably due to the strong interaction between ions and hard segments. Spin coating technology was applied to construct the iPU/IL channel layer on a Si matrix, and an ionic conductive transistor was manufactured subsequently, in which the conductive mechanism is similar with a true synapse. The resulted transistor showed an on-off ratio of 2.1 × 102, and its energy dissipation was only 64 nJ when simulating the signal transmission of a nerve synapse, which was close to the power cost in other synaptic transistors.