Exfoliation of Al-Residual Multilayer MXene Using Tetramethylammonium Bases for Conductive Film Applications

This study describes the concise exfoliation of multilayer Ti(3)C(2)T( x ) MXene containing residual aluminum atoms. Treatment with tetramethylammonium base in a co-solvent of tetrahydrofuran and H(2)O produced single-layer Ti(3)C(2)T( x ), which was confirmed via atomic force microscopy observations, with an electrical conductivity 100+ times that of Ti(3)C(2)T( x ) prepared under previously reported conditions. The scanning electron microscopy and X-ray diffraction measurements showed that the exfoliated single-layer Ti(3)C(2)T( x ) MXenes were reconstructed to assembled large-domain layered films, enabling excellent macroscale electric conductivity. X-ray photoelectron spectroscopy confirmed the complete removal of residual Al atoms and the replacement of surface fluorine atoms with hydroxy groups. Using the exfoliated dispersion, a flexible transparent conductive film was formed and demonstrated in an electrical application.