Pulse Dynamics in Reduced Graphene Oxide Electrolyte-Gated Transistors: Charge Memory Effects and Mechanisms Governing the Ion-To-Electron Transduction

Abstract

Electrolyte-gated transistors (EGTs) are widely employed in bioelectronics due to their ability to bridge ionic and electronic phenomena in a single device. Among potential materials, reduced graphene oxide (rGO) has gained significant attention due to its ambipolar current response, quantum capacitance, and tunable conductivity. However, the rGO EGT dynamic behavior remains significantly unexplored. Here, the time-dependent response of rGO EGTs is systematically investigated under gate voltage pulsing across different time scales (10 ms to 40 s) and amplitudes (up to |±0.8 V|). Significant charge memory is observed, particularly for long (40 s) pulses at 0.8 V, with effects also evident for shorter (1 s) and weaker stimuli (0.6 V). Multiple low-level (0.1 V) fast pulsing (100 ms) further demonstrate charge retention post-stimulation. All these characteristics are attributed to a complex interplay between ion entrapment within the rGO film, electrical double-layer formation, and charge transfer processes. The stability of rGO EGTs under prolonged bias stress is also examined, aiming to contribute to the development of more robust devices. These findings revealed the complex role of electrolyte ions and electronic carriers governing the ion-to-electron transduction and charge memory effects in rGO EGTs, contributing to the advancement of the next-generation bioelectronic devices.