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

Abstract

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 Bi₂Se₃ 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 Bi₂Se₃ grid electrodes by copper-atom intercalation is presented. These Cu-intercalated 2D Bi₂Se₃ 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 Bi₂Se₃ 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.

Both the optical performance and the electrical performance of transparent electrodes based on 2D Bi₂Se₃ grid nanostructures are simultaneously improved by chemical intercalation in a broadband wavelength. The high density of copper atoms accommodated between the van der Waals' gaps of Bi₂Se₃ introduces large amounts of free electrons into the host structure, which allows higher transparency, better conductivity, outstanding chemical dura­bility, and mechanical stabilities for Bi₂Se₃ grid electrodes.

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