Metal welding at room conditions of CuNi bimetallic nanowire networks Anđela Križan 1 , Laetitia Bardet 2 , Kevin Zimny 1 , Martin Romanus 1 , Kevin Critchley 3 , Daniel Bellet 2 and Mona Treguer Delapierre 1 1 Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, University of Bordeaux, France, 2 Univ. Grenoble Alpes, CNRS, France, 3 School of Physics and Astronomy, University of Leeds, UK Transparent electrodes (TE) are essential components in a large range of modern-day devices such as solar cells, touch screens, light-emitting diodes (LEDs), transparent heaters. 1 Currently, the most prominent material used for TE purposes is indium doped tin oxide (ITO). Although the latter exhibits very good physical properties in terms of electrical conductivity and optical transparency, indium is both scarce (and hence expensive), and brittle. Metallic nanowires (MNWs) represent a promising emerging material for TE due to their desirable optical and electrical properties, flexibility, as well as a more accessible price range. [2, 3] In this communication, we will explore a bimetallic CuNi NW system. Pure Cu NWs lack chemical and thermal stability due to rapid oxidation. In contrast, its alloy counterpart has significantly higher chemical stability and performs well under thermal stress. We report a novel one-step synthesis, which provides a simple way to reach desired bimetallic nanowires with various precursor’s salt ratios. In addition, due to the specific architecture of the alloyed NW, we report a novel way of optimizing conductivity in a NW network through enhancing interconnectivity, based on a reducing treatment, at room conditions. This new level of interconnectivity includes Cu NP diffusion, ultimately generating junction-like formations at the intersections between the overlapping NWs. The effect of the treatment has been analyzed by various characterization methods (HRTEM, SEM, AES, EDX, and XPS) as well as opto-electronic measurements, including nanoprobe experiments for a detailed insight of conductivity in regard to the aforementioned junctions. In addition, we have investigated the extent of protection that the Ni content provides concerning chemical and thermal stability. No significant changes in the electrical conductivity have been measured in the course of six months following the reducing treatment, deeming the TEs stable long-term. References 1. Papanastasiou, D. T., Schultheiss, A., Muñoz-Rojas, D., Celle, C., Carella, A., Simonato, J. P., & Bellet, D. (2020), Advanced Functional Materials, 30 (21), 1–33. 2. Xu, Liang & Yang, Yuan & Hu, Zeng-Wen & Yu, Shu-Hong. (2016), ACS Nano. 10. 3. Sannicolo, T., Lagrange, M., Cabos, A., Celle, C., Simonato, J. P., & Bellet, D. (2016), Small, 12(44), 6052–6075.
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