Memristive behavior of a V2C MXene/PANI:PSS composite and its applications in ammonia detection

Abstract

Memristive devices that integrate gas sensing with neuromorphic functionality have been identified as a promising route to compact, low-power, and multifunctional artificial olfaction. Herein, we presented a chemically gated memristive device based on a V₂CT_x MXene/PANI:PSS nanocomposite. A dense, strongly bonded heterostructure was constructed via HF etching followed by in situ oxidative polymerisation, enabling molecular interactions to directly modulate device conductance and thus realise gas–electrical co-operative synaptic operation. As a gas sensor, the device shows a 31.8% response to 5 ppm NH₃, with response/recovery times of 26 s/52 s and >95% signal retention over 15 days at room temperature. As a memristor, it exhibits stable bipolar resistive switching (ON/OFF > 10²) with a switching time of ∼10 ms; under preset gaseous atmospheres and pre-synaptic electrical pulses, EPSC/IPSC and PPD-type temporal plasticity are elicited. Mechanistically, protonation/deprotonation of PANI sets the chemical working point, while interfacial trap charging and barrier modulation at the V₂CT_x/PANI interface enable reversible conductance updates, mapping molecular events into time–amplitude fingerprints. At the array level, a 2 × 2 crossbar with a multi-task neural network enables parallel identification of gas type and concentration, achieving 96.2% and 94.1% accuracy, respectively. This strategy enables an end-to-end chain—from molecular transduction through synaptic modulation to algorithmic inference—within a single device, providing a scalable path to compact, low-power artificial olfaction hardware.