Liquid phase exfoliation of MoS2 nano-sheets and observation of resistive switching memory in MoS2 Nano-sheets-PVDF-HFP composite films

Abstract

To realise the true and versatile application potentials of 2-D materials like MoS2, the preparation of mono-layer or few layer nano-sheets holds the key. In the present study, we report the successful exfoliation of bulk MoS2 into few layer nano-sheets by adopting a two-step process of grinding and then two hours of ultrasonication by using a probe sonicator. The yield of exfoliation was 32 mg/10 ml and the exfoliated MoS2 was very stable without any re-stacking for more than one month. Further, the exfoliated MoS2 nano-sheets are added to Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to prepare the nanocomposite thin films. Two-terminal devices are prepared with ITO and aluminium as bottom and top electrodes, respectively on a plastic substrate. Its electrical properties are investigated to observe the electrical bistability. Nanocomposite based devices showed bipolar resistive switching memory. For composite film with 1wt.% of MoS2, resistance switching is observed with SET and RESET voltages at 2.74 V and -0.9 V respectively. Resistance ratio of the order of 104 is achieved between the ON and OFF states.