Overcoming the Limitations of MXene Electrodes for Solution‐Processed Optoelectronic Devices

MXenes constitute a rapidly growing family of 2D materials that are promising for optoelectronic applications because of numerous attractive properties, including high electrical conductivity. However, the most widely used titanium carbide (Ti₃ C₂ T_x ) MXene transparent conductive electrode exhibits insufficient environmental stability and work function (WF), which impede practical applications Ti₃ C₂ T_x electrodes in solution-processed optoelectronics. Herein, Ti₃ C₂ T_x MXene film with a compact structure and a perfluorosulfonic acid (PFSA) barrier layer is presented as a promising electrode for organic light-emitting diodes (OLEDs). The electrode shows excellent environmental stability, high WF of 5.84 eV, and low sheet resistance R_S of 97.4 Ω sq^-1 . The compact Ti₃ C₂ T_x structure after thermal annealing resists intercalation of moisture and environmental contaminants. In addition, the PFSA surface modification passivates interflake defects and modulates the WF. Thus, changes in the WF and R_S are negligible even after 22 days of exposure to ambient air. The Ti₃ C₂ T_x MXene is applied for large-area, 10 × 10 passive matrix flexible OLEDs on substrates measuring 6 × 6 cm. This work provides a simple but efficient strategy to overcome both the limited environmental stability and low WF of MXene electrodes for solution-processable optoelectronics.