Synthesis, Properties, and Application of Ultrathin and Flexible Tellurium Nanorope Films: Beyond Conventional 2D Materials

Abstract

Nanomaterials that can be easily processed into thin films are highly desirable for their wide range of applicability in electrical and optical devices. Currently, Te‐based 2D materials are of interest because of their superior electrical properties compared to transition metal dichalcogenide materials. However, the large‐scale manufacturing of these materials is challenging, impeding their commercialization. This paper reports on ultrathin, large‐scale, and highly flexible Te and Te–metal nanorope films grown via low‐power radiofrequency sputtering for a short period at 25 °C. Additionally, the feasibility of such films as transistor channels and flexible transparent conductive electrodes is discussed. A 20 nm thick Te–Ni‐nanorope‐channel‐based transistor exhibits a high mobility (≈450 cm2 V−1 s−1) and on/off ratio (105), while 7 nm thick Te–W nanorope electrodes exhibit an extremely low haze (1.7%) and sheet resistance (30 Ω sq−1), and high transmittance (86.4%), work function (≈4.9 eV), and flexibility. Blue organic light‐emitting diodes with 7 nm Te–W anodes exhibit significantly higher external quantum efficiencies (15.7%), lower turn‐on voltages (3.2 V), and higher and more uniform viewing angles than indium‐tin‐oxide‐based devices. The excellent mechanical flexibility and easy coating capability offered by Te nanoropes demonstrate their superiority over conventional nanomaterials and provide an effective outlet for multifunctional devices.

Liquid–Liquid Interface-Assisted Self-Assembly of Ag-Doped ZnO Nanosheets for Atomic Switch Application

“…Among the two-dimensional (2D) van der Waal materials, ZnO nanosheet (NS) is a potential candidate for various electronic, optical, and optoelectronic devices such as sensors, photocatalysts, and memristors − due to its exceptional flexibility, optical transparency, and high degree of crystallinity. − Doping of 2D ZnO using a small quantity of metal atoms can further offer band gap tunability and modulation of electrical conductivity while maintaining its 2D crystallinity close to that of its parent structure. For surface-supported device applications, which require large-area uniform films, techniques such as bottom-up physical/chemical vapor deposition and top-down micromechanical exfoliation are widely explored. − Similarly, free-standing films have been reported by using techniques such as top-down sonochemical/liquid phase exfoliation (LPE). However, all these techniques yield nanosheets, at best at the nanoscale lateral dimensions, which poses the major limitation in device fabrication. − Thus, it is technologically required to develop experimentally facile and economical protocols to obtain a large-area film constisting of nanosheets.…”