Control of MXenes' Electronic Properties through Termination and Intercalation

MXenes are an emerging family of highly-conductive 2D materials which have demonstrated state-of-the-art performance in electromagnetic interference shielding, chemical sensing, and energy storage. After de-intercalation, vacuum annealing at higher temperatures led to surface de-functionalization and improved electronic conductivity. Regarding the effects of termination, vacuum annealing was shown to cause partial surface termination removal and increases in the MXene electronic conductivity. Electronic transport properties of MXenes after heat treatments were measured in a Quantum Design EverCool II Physical Property Measurement System. X-ray photoelectron spectroscopy analysis was performed in a spectrometer using a 100 µm monochromatic Al Ka X-ray beam. Background contributions to the measured intensities were subtracted using a Shirley function prior to quantification and deconvolution. The X-ray diffraction data were acquired from vacuum-filtered films of the same solution used for the in situ TEM study.