Size effect enabling additive-free MXene ink with ultrahigh conductivity for screen printing of wireless electronics

Facile preparation of additive-free inks with both high viscosity and high conductivity is critical for scalable screen printing of wireless electronics, yet very challenging. MXene materials exhibit excellent conductivity and hydrophilicity, showing great potential in the field of additive-free inks for screen printing. Here, we demonstrate the synthesis of additive-free two-dimensional (2D) titanium carbide MXene inks, and realize screen-printed MXene wireless electronics for the first time. The viscosity of MXene ink is solely regulated by tuning the size of MXene nanosheet without any additives, hence rendering the printed MXene film extremely high conductivity of 1.67 x 10(5) S/m and fine printing resolution down to 0.05 mm on various flexible substrates. Moreover, radio frequency identification (RFID) tags fabricated using the additive-free MXene ink via screen printing exhibit stable antenna reading performance and superb flexibility. This article, thus offers a new route for the efficient, low-cost and pollution-free manufacture of printable electronics based on additive-free MXene inks.