Porphyrin MOF nanosheets used for light-mediated multilevel memristive switching†

Abstract

Metal–organic frameworks (MOFs), self-assembled by metal ions and organic ligands, have been utilized as active layers in resistive random-access memory (RRAM) devices due to their tunable composition and structure advantages, high porosity, and diverse interactions between guest molecules and host frameworks. As one kind of special MOF, MOF nanosheets not only inherit the benefits of MOFs but also present unique two-dimensional nanoscale thicknesses. Their special properties make them beneficial for fabricating MOF films. Thus, they could be promising materials for RRAM devices. Herein, we synthesized two porphyrin MOF nanosheets and then fabricated MOF films by spin-coating. After that, we used the films for resistive switching (RS) layers in memory devices. The as-fabricated RRAM devices exhibit write-once-read-many-times memory characteristics and good nonvolatile stability. Furthermore, due to the unique luminescence of the porphyrin linker, we investigated the light-induced resistive switching characteristics. The result shows that these porphyrin-based MOF nanosheet films exhibited ternary memory properties. This RS modulation is likely related to the photoinduced electrons and holes forming along channels consisting of porphyrin molecules. This MOF-based light-mediated memory device can be a candidate for achieving environment-responsive devices and has applications in information storage devices.