Room-Temperature Ionic Liquid-Doped Ceramic Composites for Low-Voltage Synaptic Devices

Abstract

Room-temperature processing of ionic liquid–doped ceramic composites offers a sustainable, low-cost route to neuromorphic devices that operate at sub-volt switching thresholds. In this work, we report the fabrication and characterization of Al₂O₃–SiO₂ ceramic membranes functionalized with 1-ethyl-3-methylimidazolium triflate (EMIM⁺·OTf⁻) via a simple, solvent-free mixing and curing protocol at ambient temperature. Morphological analysis (SEM, EDX) confirms uniform IL dispersion within the ceramic pore network, while thermogravimetric and contact-angle measurements demonstrate enhanced moisture retention and surface wettability. Electrical testing of Au/EMIM-ceramic/Au cross-bar devices reveals bipolar resistive switching with set and reset voltages as low as +0.45 V and –0.40 V, respectively, and an on/off ratio exceeding 10³. Synaptic functionalities—including paired-pulse facilitation, paired-pulse depression, and spike-timing-dependent plasticity—are emulated with energy consumption per event below 5 pJ. Devices retain stable conductance states for over 10⁴ s and endure more than 10³ switching cycles without performance degradation. Compared to undoped ceramics, EMIM doping reduces activation barriers and stabilizes conductive filament formation under low electric fields. These findings highlight the promise of room-temperature IL–ceramic composites for scalable, energy-efficient in-memory computing and pave the way for integrated neuromorphic architectures in flexible and wearable electronics.