A testable weighting factor for accurate analysis of the organic electrochemical transistors' transient response behavior

Organic electrochemical transistors (OECTs) have shown significant potential in applications ranging from bio-sensing to neuromorphic devices and cell impedance monitors. Transient response plays a pivotal role in varied applications. However, it is still challenging to accurately analyze the complex equilibrium process of transient response. The factor of f is a constant of proportionality about the amplitude ratio of the source current to the gate current. It plays an important role in the analysis of the transient response. Herein, we establish a test method for measuring the source and gate current. Our model fits almost perfectly with the drain current following a gate voltage step when the f is directly obtained from the source current amplitudes divided by gate current amplitudes at the current high-frequency spectra of an OECT. We further deduced empirical expressions for f as a function of the voltage settings, the channel's geometric parameters, and the concentration of the solution. This work is significant for understanding the potential mechanisms of OECT's transient response behavior.