Clean, Ice-Assisted Transfer of Flexible Transparent Copper Mesh Films for Electrothermal Heating and Terahertz Shielding.

Abstract

Flexible transparent conductive films (TCFs) are essential components for emerging flexible electronics. Among various candidates, metal mesh films offer an effective structural route to balance transparency and conductivity. However, metal mesh films often suffer from structural damage, interfacial residues, and poor compatibility with different flexible substrates during a traditional transfer process. Here, we reported an ice-assisted transfer strategy using temporary ice layers as transfer media, achieving efficient transfer of copper (Cu) mesh with clean, low damage, and substrate compatibility. The transferred Cu mesh film achieves a transmittance of 82.0% at 550 nm, and a sheet resistance of 144 mΩ/□ on TPU substrates, showing a remarkable figure of merit (FoM) of 12 524. The Cu mesh film maintained similar performance on various substrates, including hard glass, flexible polymers, skin, etc. Based on the transferred Cu mesh film, flexible transparent heaters are fabricated. The heater exhibited a high saturated temperature at a low heating voltage (>200 °C at 1.0 V), high stability (>300 min), and fast heating rate (>10 °C/s). The transparent Cu mesh film also demonstrated an average electromagnetic interference shielding effectiveness (EMI SE) of 19.0 dB in the 0.2-1.6 THz. By multilayer stacking, the resulting film showed an average EMI SE of 46.4 dB. These results indicate that the ice-assisted transfer strategy ensures the integrity of the metal mesh while retaining its superior optoelectronic characteristics and functional adaptability, providing an efficient and clean method for preparing TCFs.