Researchers at the University of Washington have made a breakthrough in understanding the behavior of organic electrochemical transistors (OECTs), which play a crucial role in bridging the gap between biology and technology. These devices are essential components in implantable biosensors and other medical devices, as they allow for the flow of ions and electrons, enabling communication between technology and the human body. However, scientists have struggled to explain a puzzling lag in the activation of OECTs. The recent study led by David Ginger, a UW professor of chemistry, has shed light on this phenomenon, providing insights that could lead to the development of more efficient and customized OECTs for various applications.
The study published in Nature Materials revealed that the activation of OECTs involves a two-step process, while deactivation occurs in a single step. When an OECT is switched on, ions travel across the transistor followed by the invasion of more charge-bearing particles, causing the current to reach operational levels. On the other hand, deactivation involves a uniform drop in charged chemicals across the transistor, swiftly interrupting the flow of current. This understanding of the underlying mechanisms of OECT behavior opens up possibilities for designing improved iterations of these devices for a range of applications.
OECTs are predominantly made from flexible, organic semiconducting polymers that operate in liquid environments containing salts and other chemicals. The challenge lies in balancing effective ion transport with electronic conductivity in the material design of OECTs. By studying OECTs that change color in response to electrical charge, the research team was able to observe the activation lag under a microscope and identify the chemical processes involved. This knowledge could be instrumental in developing OECTs with optimal characteristics tailored to specific requirements in biosensing, brain-inspired computation, and other fields.
Previous research has highlighted the importance of polymer structure in the function of OECTs, particularly their flexibility when operating in fluid-filled environments rich in biological compounds. The recent study builds upon this knowledge by directly linking the structure of OECTs to their performance. By varying the composition and arrangement of polymers, researchers can manipulate activation lag times and other parameters to customize OECTs for different applications. This flexibility in design presents opportunities for accelerating the development of OECTs with specialized features for various scientific and medical purposes.
Beyond biosensing, OECTs have diverse applications in studying nerve impulses, artificial neural networks, and brain-inspired computing. These broad applications require the development of next-generation OECTs with specific characteristics such as fast activation and deactivation times. The recent breakthrough in understanding OECT behavior has laid the groundwork for advancing research in this area, potentially leading to faster and more efficient devices for a wide range of technological and medical applications. The interdisciplinary collaboration between researchers at the University of Washington, Okinawa Institute of Science and Technology, and Zhejiang University has paved the way for future advancements in the field of organic electrochemical transistors.
