Efficient physical delamination of Ti₃C₂T_x MXene under periodic and constant shear field of Taylor vortex flow

Employing Taylor vortex flow (TVF), we have devised an innovative technique for the delamination of MXene without using a chemical intercalant and demonstrated the enhanced optoelectronic characteristics of this delaminated MXene through their successful implementation in light emitting diode (LED). The pairwise toroidal fluid motion of TVF was induced by the rotation of the inner cylinder in the Couette-Taylor (CT) reactor. Due to periodic and constant shear field, TVF was highly efficient for the exfoliation of MXene. So, the continuous exfoliation process using CT reactor always showed 8.1 ∼ 12.5 times higher delaminated MXene (d-Ti₃C₂T_x) yield than that using a conventional mixing tank (MT) reactor which generated turbulent eddy flow (TEF) by impeller agitation. As such, 8.26 mgּ/mL (42.90 % of recovery ratio) of d-Ti₃C₂T_x was obtained in CT reactor at 1300 rpm of inner cylinder rotation speed and 24 min of mean residence time (MRT). In comparison, d-Ti₃C₂T_x in MT reactor at 3000 rpm of agitation speed and 24 min of MRT was 0.66 mgּ/mL (3.42 % of recovery ratio). In addition, d-Ti₃C₂T_x in TVF was thinner and wider than that in TEF. So, the d-Ti₃C₂T_x was homogeneously suspended without sedimentation and oxidation in aqueous suspension over 30 days. In addition, d-Ti₃C₂T_x in the TVF was applied to the transparent conducting electrode of inorganic CsPbBr₃ perovskite light emitting diodes (PeLEDs). The transparent conducting oxide-free PeLED had 62.52 cd/A of maximum current efficiency and 14.48 % of maximum external quantum efficiency, which is comparable to the best performance of ITO-based inorganic CsPbBr₃ PeLEDs.