Bio-inspired surface modification of MoS2 nanosheets with gallium phthalocyanine for brain-like synaptic memristors

Abstract

Memristors based on two-dimensional (2D) layered materials with excellent electrical behavior are promising candidates for bio-inspired artificial computing devices. However, the low solubility of 2D layered materials makes them incompatible with solution-processing memristor fabrication, and the complexity of nanocomposite components exacerbates random electrical behavior with unclear mechanisms. In this contribution, inspired by mussel chemistry, we utilized polydopamine as a bridge to covalently graft gallium phthalocyanine to MoS₂ nanosheets. The prepared MoS₂-PDA-tBu₄PcGaCl nanocomposite exhibited great solubility in conventional organic solvents. Conductive channels could be specifically formed between phthalocyanine and MoS₂ nanosheets, with highly localized behavior that restricted chaotic resistive switching characteristics. The 64 states of device conductance were stepwise modulated through direct current (DC) scanning, which enabled the execution of computing-in-memory tasks. Then, behaviors closely resembling biological synapses were also determined by the device due to the dynamic conversion between the formation and destruction of conductive channels. This study offers a new idea to enhance the resistive switching performance and memristor manufacturability by a molecular engineering approach.