Fig. 1: Bistability emerges from the interplay of enthalpy and entropy.
From: Bistable organic electrochemical transistors: enthalpy vs. entropy
a–c The Gibbs free energy function G(ψ) governs the chemical potential μ(ψ), which itself determines the transfer curve of an OECT. In the case of dominating entropy, the system is monostable along the ψ-axis, with a monotonic chemical potential and an accordingly shaped transfer curve (orange). For rising enthalpy, the system gets bistable, causing a non-monotonic chemical potential, which results in a bistable switching behavior (blue). d Generalized setup of an OECT. Devices in this work typically employed a side-gate architecture (Fig. S2). e Chemical structures of the OECT solid-state electrolyte and channel material used to study the bistability, with f a representative, experimental transfer curve (VDS = −0.2 V). g Two distinct drain current levels are found when operating the OECT and holding a 0 V gate bias, approaching either from the on- or the off-state.
