Guo Jiajie, Chen Shinya E, Giridharagopal Rajiv, Bischak Connor G, Onorato Jonathan W, Yan Kangrong, Shen Ziqiu, Li Chang-Zhi, Luscombe Christine K, Ginger David S
Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA.
Department of Chemistry, University of Washington, Seattle, WA, USA.
Nat Mater. 2024 May;23(5):656-663. doi: 10.1038/s41563-024-01875-3. Epub 2024 Apr 17.
Understanding the factors underpinning device switching times is crucial for the implementation of organic electrochemical transistors in neuromorphic computing, bioelectronics and real-time sensing applications. Existing models of device operation cannot explain the experimental observations that turn-off times are generally much faster than turn-on times in accumulation mode organic electrochemical transistors. Here, using operando optical microscopy, we image the local doping level of the transistor channel and show that turn-on occurs in two stages-propagation of a doping front, followed by uniform doping-while turn-off occurs in one stage. We attribute the faster turn-off to a combination of engineering as well as physical and chemical factors including channel geometry, differences in doping and dedoping kinetics and the phenomena of carrier-density-dependent mobility. We show that ion transport limits the operation speed in our devices. Our study provides insights into the kinetics of organic electrochemical transistors and guidelines for engineering faster organic electrochemical transistors.
了解影响器件切换时间的因素对于有机电化学晶体管在神经形态计算、生物电子学和实时传感应用中的实现至关重要。现有的器件运行模型无法解释在累积模式有机电化学晶体管中关断时间通常比开启时间快得多的实验现象。在这里，我们使用原位光学显微镜对晶体管沟道的局部掺杂水平进行成像，并表明开启过程分两个阶段发生——掺杂前沿的传播，随后是均匀掺杂——而关断过程在一个阶段发生。我们将更快的关断归因于工程因素以及物理和化学因素的综合作用，包括沟道几何形状、掺杂和去掺杂动力学的差异以及载流子密度依赖性迁移率现象。我们表明离子传输限制了我们器件的运行速度。我们的研究为有机电化学晶体管的动力学提供了见解，并为设计更快的有机电化学晶体管提供了指导方针。
