Face‐on Orientation Matches Vertical Organic Electrochemical Transistors for High Transconductance and Superior Non‐Volatility

Abstract

The recently developed vertical structure of organic electrochemical transistors (OECTs) can integrate volatile and non‐volatile functions into one reconfigurable device, making it highly promising. However, comparing with the conventional planar OECT (c‐OECT), the understanding of vertical OECT (v‐OECT) working principles and device engineering strategies is still lacking, impeding rational optimization. Since a major difference between c‐ and v‐OECTs is their charge transport directionality, which is highly influenced by crystallite orientations, the orientation–device structure match thus becomes an important yet outstanding topic for OECTs. Herein, using an n‐type small molecule IDIC‐MEG, investigate how much impact such match can have on OECT performance. The IDIC‐MEG c‐OECT fails to work due to the seriously hindered in‐plane electron transport by face‐on orientation. Surprisingly, simply changing the device structure from planar to vertical allows the resultant v‐OECT to exhibit the highest reported transconductance (46.3 mS) among all small‐molecule OECTs, thanks to the match between face‐on orientation and the vertical structure. Such match also leads to excellent non‐volatility, including highly predictable programmability and good operational stability. This work, for the first time, explicitly demonstrates the significance of orientation–device structure match for OECT optimization, establishing new guidelines for achieving high‐performance volatile and non‐volatile OECTs.

Electrolyte engineering in organic electrochemical transistors for advanced electrophysiology

“…In a sandwich-type vertical structure, the channel length is determined by the thickness of the active layer, typically around 0.1 μm. Notably, across various device configurations, molecular orientation plays a crucial role in determining both ionic drift [53] and charge carrier transport pathways [54] , thereby affecting An innovative approach to reduce the response time (τ) involves integrating the channel material with the electrolyte. In particular, an internal ion-gated OECT (IGT), a unique type that incorporates hydrated ion reservoirs within a conducting polymer channel, was innovated [55] .…”

“…Can electrolyte engineering address the aforementioned challenges comprehensively and generate highperformance, high-speed OECTs in large-scale integrated circuits with minimal crosstalk in physiological media? In an in vitro setting, employing a solid electrolyte could facilitate the separation of individual channels, enabling individual gating [53] . When applied in an aqueous in vivo context, a solid-like electrolyte that exhibits biocompatibility, adhesive properties to tissues, and the ability for patterning, thereby supporting high-density configurations, has the potential to enable high-quality signal mapping with enhanced spatial resolution and reduced crosstalk.…”

基于有机混合离子-电子导体材料的有机电化学晶体管

“…此外, 最近开发的垂直结构有 机电化学晶体管(v-OECTs)可以将易失性和非易失性 功能集成到一个可重构器件中, 具有很高的应用前 景 [78] . Ma等 [69] 总体而言, 改进和创新的材料设计和器件结构多 元化的发展已经将OECTs推向了生物电子学领域的前 沿 [4,6] .…”