Approaching the Limits of Transmittance and Sheet Resistance in MXene through Nanoimprinting-Blading of Inks

Abstract

Developing an advanced transparent conductive electrode (TCE) as a substitute for the fragile and high-cost indium tin oxide (ITO) is the top priority in the coming smart electronics era. Although two-dimensional transition metal carbides and nitrides (MXenes) have revealed great potential in the competition, the figure of merits (FoM_e, defined as the ratio of direct current conductivity to optical conductivity) of reported MXenes TCEs are far below the minimum industrial requirement. Herein, we report on the breaking of FoM_e limitation by a hybrid nanoimprint-blading technique to construct embedded MXene grids, where the fine slot channels are filled with MXene flakes and the space beyond is left empty, allowing more visible light to pass through, thus substantially improving the transmittance. Such a strategy decouples the correlation between transmittance and sheet resistance and achieves their individual regulation. As a result, we obtain an ultrahigh FoM_e (∼84) surpassing most of other nonmetal TCEs and even being competitive to ITO. We demonstrate the application of MXene grid TCE in the electrochromic device, showing satisfactory switching time and excellent stability (>38,000 cycles). This work opens vast opportunities for MXenes to construct advanced flexible electronics for industrial applications.