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

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-tBu(4)PcGaCl 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.