Partial-to-fully oxidized spectrum of Ti3C2T x MXene-derived TiO2 free-standing films for nonvolatile high endurance memristive data storage

As an exemplary member of the MXene family belonging to the class of two-dimensional materials, titanium carbide (Ti3C2Tx) MXene stands bright and is explored owing to its exceptional tunable properties. The full ambient oxidation of MXene in a spectrum of varying elevated temperatures toward the application of memristor devices is reported for the first time in this work. A Ti3C2Tx MXene free-standing film is oxidized in air from the temperature of 100 to 700 °C upon which the MXene completely transforms into the TiO2 film yet retaining its free-standing nature in the form of MXene-derived TiO2 films. Extensive surface, morphological, and bulk characterizations, such as x-ray photoelectron spectroscopy, transmission electron microscopy, and x-ray diffraction, confirmed the increasing Ti–O and decreasing Ti–C bond strength amid increasing oxidation. Furthermore, exceptional resistance switching properties are unveiled employing these heated MXene devices in tri-layer memristors utilizing flexible reduced graphene oxide as electrodes. The memristor device utilizing Ti3C2Tx MXene heated at 700 °C exhibited outstanding performance compared to the other series of devices with low switching voltage, a high OFF/ON ratio of >102, cycle-to-cycle repeatability, and exceptional endurance of over 6000 cycles. This work on MXene-derived TiO2 free-standing films will lay open ways to obtain oxide based flexible electronic devices through easy fabrication methods along with the possible capability to mimic unmatched synaptic features.