Abstract
This study aims to contribute to the burgeoning field of brain-inspired computing by expanding it beyond conventional fabrication methods. Herein, the obstacles toward the effective inkjet printing process are encountered and the electrical characteristics are explored, providing new insights into the reliability aspects of fully printed Ag/a-TiO2/Ag electronic synapses. The versatility of the approach is further enhanced by the highly stable in-house-developed a-TiO2 ink, exhibiting optimal shelf life of five months and repeatable jetting, producing layers with nanoscale thickness resolution. Most importantly, device electrical characterization reveals synaptic dynamics, leading to activity-dependent conductance state retention and adaptation characteristics, implying inherent learning capabilities. The synaptic dynamics are attained by solely adjusting the duty cycle of the applied pulsed voltage trigger, while keeping amplitude and polarity fixed, a method readily compatible with realistic applications. Furthermore, I-V analysis demonstrates a dynamic range dependence on a-TiO2 layer thickness and conduction mechanism that is akin to the conventionally developed electronic TiO2 synapses. The developed devices provide a time- and cost-effective ecologically benign alternative toward biomimetic signal processing for future flexible neural networks.