High-Performance Transparent and Conductive Films with Fully Enclosed Metal Mesh

Metal mesh films as a kind of transparent conductive electrodes (TCEs) have shown high promise in various optoelectronic devices but are still challenged by a combination of high conductivity and transparency, mechanical robustness, and uniform electric field. Herein, we demonstrate a new concept of transparent and conductive films with a fully enclosed metal mesh, which is embedded in deep microcavities and is coated with a conductive polymer layer to combine these metrics. To ensure high conductivity and transparency, metal ink is filled into the fine (down to submicrometers) and deep mesh microcavities by electrowetting-assisted blading with low square resistances of 0.4 and 2.69 Ω sq^-1 at typical transmittances of 76.9 and 87.4%, respectively. The covered thin conductive polymer layer improves the electric field uniformity of metal mesh films by at least three orders of magnitude. The fully enclosed metal mesh films exhibit excellent mechanical flexibility, indicated by the fact that the resistance is almost unchanged after 10,000 bending cycles at a bending radius of ∼5 mm. Based on the fully enclosed metal mesh films, the emission intensity of alternating current electroluminescent devices is improved by more than three times compared with that in the case of solely using common metal mesh films.