An Artificial Olfactory Chemical‐Resistant Synapse for Training‐Free Gas Recognition

Abstract

Transferring the concept of chemical‐driven responses into artificial intelligence technology holds the key to mimicking olfactory for neuromorphic computing of chemical recognition. Currently, artificial olfactory systems are designed based on chemical sensor arrays. Time‐dependent responses of the sensor arrays are processed by artificial neural networks for recognition. However, the sensors generate instantly volatile responses, and algorithms for the processing of the time‐dependent responses have not been involved. The recognition accuracy and speed are severely impeded. A sensor array can only achieve an accuracy of 90% after at least 5 training epochs. Herein an artificial olfactory chemical‐resistant synapse consisting of 3D hierarchical WO3@WO3 nanofibers are demonstrated. The nanofibers exhibit persistent resistance responses through chemical exposures due to the strong chemisorption of water molecules. Typical synaptic behaviors including paired‐pulse facilitation, long‐term −1 short‐term memory, and learning experience have been achieved. Next, a recurrent neural network that is committed to processing the time‐dependent data is used to identify gas‐phase chemicals of 3‐hydroxy‐2‐butanone, triethylamine, and trimethylamine. Training‐free gas recognition has been realized by a WO3@WO3 nanofiber synapse only, in which the accuracy is above 90% at the first epoch. The results have great potential to satisfy stringent performance requirements on artificial perception systems.

Recent Progress in Wearable Near-Sensor and In-Sensor Intelligent Perception Systems

“…Similarly, single-walled carbon nanotubes (SWCNTs) combined with olfactory receptor-derived peptides (ORPs) are useful for detecting harmful concentrations of trimethylamine (TMA) with a lower limit of 0.01 ppq [126]. Through the chemical reaction, chemical molecules can transform information into electric signal [127]. Instead of inorganic material, organic material is more prevalent in olfactory sensors due to their greater variety of chemical bonds.…”