Overcoming the Tradeoff\nof Visible Transparency and\nElectrical Conductance via Dual Smoothing of Dielectric/Metal Interfaces\nin Cu-Thin-Layer-Based Transparent Electrodes

The rapid advancement of flexible optoelectronic devices,\nsuch\nas light-emitting diodes, solar cells, and electrochromic devices,\nnecessitates the development of high-performance flexible transparent\nelectrodes (TEs). Dielectric/metal/dielectric (DMD)-type TEs are promising\nalternatives to conventional indium tin oxide (ITO) due to the high\nelectrical conductance, excellent visible transparency, and sufficient\nmechanical flexibility. However, the tradeoff between electrical conductance\nand visible transparency poses a challenge to performance enhancement.\nThis study introduces an Ar-ion-mediated interface modification method\nto address this tradeoff by dual smoothing of dielectric/metal interfaces\nin TiO<sub><i>x</i></sub>/Cu/ZnO TEs. Implementing this\ndual smoothing methodology significantly enhances both electrical\nconductance and visible light transmittance, achieving a Haacke figure\nof merit 200% higher than that of an unmodified otherwise identical\nstructure. The highest figure of merit is 0.113 Ω<sup>–1</sup>, a record high for Cu-thin-layer-based DMD TEs, far surpassing ITO\nelectrode values. Further, the enhanced optoelectronic performance\nremains highly durable under severe and simultaneous electrical, thermal,\nand mechanical stresses, showcasing the potential for significant\nadvances in flexible optoelectronics.