Inkjet-Printed Ambipolar Vertical Organic Electrolyte-Gated Transistor with a Laser-Cut Channel for Synaptic Applications

Significant progress has been made in developing bio-inspired synaptic systems and artificial multisensory neurons for memory and perception in recent years. In particular, the vertical electrolyte-gated transistor has gained considerable attention due to its unique features arising from ionic and/or electronic current modulation, such as high transconductance, and high operating frequency. These attributes make this device highly suitable for artificial synapse applications. The channel length (L) of the vertical electrolyte-gated transistor is determined by the vertical separation between the source and drain, which naturally corresponds to the thickness of the organic semiconductor. This feature allows for downscaling the ionic-electronic transport pathway to the hundred-nanometer range. However, the need for sophisticated nanolithography techniques in the fabrication process has hindered the large-scale commercial application of vertical electrolyte-gated transistors. In response to this challenge, we propose a simple device fabrication technique that utilizes inkjet printing and laser structuring to achieve high-performance ambipolar vertical electrolyte-gated transistors, demonstrating great promise for synaptic applications. The integration of inkjet printing and laser structuring techniques enables precisely patterned solid-state electrolytes, organic semiconductors, and gate contact, resulting in tunable transconductance and threshold voltage. We believe that this work presents a simple and effective fabrication protocol for devices, offering excellent application potential for vertical-channel organic electrolyte-gated transistors in large-scale commercial fields.