Dielectrophoretic direct assembling of Mxene flakes at the level of screen-printed interdigitated microelectrodes and their evaluation in gas sensing applications

Controlling, orientating, and assembling 2D materials is critical for their successful exploitation as active elements in various applications, particularly for sensors. Despite the increased interest in exploiting the properties of MXenes, to date, the direct dielectrophoretic assembly of this category of materials has not been reported. Thus, this work presents an experimental study on dielectrophoretic assembly of pristine MXene flakes at the level of screen-printed interdigitated microelectrodes. The development of MXene uniaxial ‘bridges’ across electrode micro-gaps can be controlled by convenient dielectrophoretic parameters such as voltage and frequency, which are thoroughly discussed. Moreover, appropriate frequencies for avoiding parasitic electrokinetic phenomena (AC electro-osmosis, electrothermal effect) that hamper the application of dielectrophoresis were identified. Finally, the proposed methodology for assembling MXene flakes demonstrates its feasibility of being used for development of chemiresistors as of satisfactory response of pristine MXene ‘bridges’ to ethanol atmosphere.