A tunable ion relaxation process of a thermoelectric system for adjustable memory of thermal perception

Abstract

Ionic thermoelectric materials based on the Soret effect exhibit sensitive temperature perception and memory behavior due to the differential ion thermodiffusion under temperature gradient and spontaneous ion relaxation after temperature withdrawal. This principle has become an alternative material scheme for artificial tactile neural systems. However, modulating the ion relaxation process of thermoelectric systems to match synaptic plasticity in humanoids for short- and long-term memory remains challenging. Hence, the strategy of interfacial modification of ion diffusion channels is proposed for interfering with ion relaxation. The interfacial molecules, which exhibit repulsive interactions with ion species, can increase the coulombic interactions between the ion pairs of the bulk phase through long-range induction, which results in ion diffusion in large-size clusters, and thus prolong the relaxation time of the ions. Conversely, the relaxation of ions will be accelerated. Furthermore, this strategy of interfacial modification is extended to paper-based porous materials to construct a neuromorphic integrated system for temperature perception and memory. Relying on the long-range induced interactions of interfacial molecules to accelerate or delay the relaxation process of ions, the regulation of time scale of temperature memory is successfully achieved, which meets the functional requirements of artificial tactile neural systems for short- and long-term temperature memory.