Pyrolytically Modified Polyacrylonitrile‐Covalently Grafted MoS 2 Nanosheets for a Nonvolatile Rewritable Memory Device

The electrical conductivity of laterally ordered polyacrylonitrile (PAN) can be improved by pyrolytic modification. Newly synthesized MoS 2 nanosheets covalently grafted with PAN (MoS 2 ‐PAN) do not exhibit any electrical switching and memory effect in an indium tin oxide (ITO)/MoS 2 ‐PAN/Au device under applied bias voltages. After annealing at 220 °C for 4 h, the resultant pyrolytically modified product “pyro‐MoS 2 ‐PAN” shows good nonvolatile rewritable memory performance, with a large ON/OFF current ratio of 4 × 10 4 and lower switching on and off voltages of −1.09 and 1.24 V. Highly reproducible memory I – V loops of more than 60 consecutive cycles are achieved without clear degradation of the ON and OFF states. The first oxidation potential of pyro‐MoS 2 ‐PAN is cathodically shifted to over 530 mV lower than that of MoS 2 ‐PAN, indicating the higher hole injection of pyro‐MoS 2 ‐PAN when compared to MoS 2 ‐PAN. As expected, the nonannealed MoS 2 /PAN blend‐based device does not show any memory effect under the same experimental condition. After annealing at 220 °C for 4 h, the blends exhibit unstable electrical switching and rewritable memory performance.