Flexible, Conformal Organic Synaptic Transistors on Elastomer for Biomedical Applications

Bioelectronics in synaptic transistors for future biomedical applications, such as implanted treatments and human-machine interfaces, must be flexible with good mechanical compatibility with biological tissues. The rigid nature and high deposition temperature in conventional inorganic synaptic transistors restrict the development of flexible, conformal synaptic devices. Here, the dinaphtho[2,3-b:2,3-f]thieno[3,2-b]-thiophene organic synaptic transistor on elastic polydimethylsiloxane is demonstrated to avoid these limitations. The unique advantages of organic materials in low Young's modulus and low temperature process enable seamless adherence of organic synaptic transistors on arbitrary-shaped objects. On 3D curved surfaces, the essential synaptic functions, such as potentiation/depression, short/long-term synaptic plasticity, and spike voltage-dependent plasticity, are successfully realized. The time-dependent surface potential characterization reveals the slow polarization of dipoles in the dielectric is responsible for hysteresis and synaptic behaviors. This work represents that organic materials offer a potential platform to realize the flexible, conformal synaptic transistors for the development of wearable and implantable artificial neuromorphic systems.