Angled-stencil lithography based metal mesh/Ti3C2Tx MXene hybrid transparent electrodes for low-power and high-performance wearable thermotherapy

Transparent and wearable devices have aroused immense research interest for their widespread applications, however, the fabrication of electrically and thermally homogeneous devices is an outstanding challenge to manifest low-power wearable thermotherapy devices. Here, we developed simple angled-stencil lithography to fabricate Ag micro-mesh based transparent conducting electrodes (TCEs) and demonstrated a low sheet resistance of 0.8 omega (-1) and high transmittance of 83%, benefiting from the seamless junctions and highly aligned microstructures. The synergy between 2D Ti3C2Tx MXenes and Ag micro-mesh elucidated electrical and thermal uniformity of the hybrid TCEs with a high figure of merit (FOM) value of 1.5 x 10(3). The hybrid Ag micro-mesh/Ti3C2Tx MXene heaters are mechanically robust and exhibited a homogeneous temperature distribution (similar to 99 degrees C) with a fast response time (18-28 s). The efficient Joule heating of Ag micro-mesh and perfect thermal management of Ti3C2Tx MXenes together unraveled unprecedented thermal resistance (675 degrees C cm(2) W-1) and record-low actuation voltage (1.2 V). The hybrid transparent heater is successfully employed on a human wrist as a skin-mountable thermotherapy device while the low-power consumption enabled portability for transit mode operation. The low-power consumption and portability of hybrid TCEs empower next-generation wearable thermotherapy applications.