Chemical Intercalation of Topological Insulator Grid Nanostructures for High-Performance Transparent Electrodes

2D layered nanomaterials with strong covalent bonding within layers and weak van der Waals' interactions between layers have attracted tremendous interest in recent years. Layered Bi₂ Se₃ is a representative topological insulator material in this family, which holds promise for exploration of the fundamental physics and practical applications such as transparent electrode. Here, a simultaneous enhancement of optical transmittancy and electrical conductivity in Bi₂ Se₃ grid electrodes by copper-atom intercalation is presented. These Cu-intercalated 2D Bi₂ Se₃ electrodes exhibit high uniformity over large area and excellent stabilities to environmental perturbations, such as UV light, thermal fluctuation, and mechanical distortion. Remarkably, by intercalating a high density of copper atoms, the electrical and optical performance of Bi₂ Se₃ grid electrodes is greatly improved from 900 Ω sq^-1 , 68% to 300 Ω sq^-1 , 82% in the visible range; with better performance of 300 Ω sq^-1 , 91% achieved in the near-infrared region. These unique properties of Cu-intercalated topological insulator grid nanostructures may boost their potential applications in high-performance optoelectronics, especially for infrared optoelectronic devices.