Synthesis of oxidation-resistance copper nanowires-formate for high-performance transparent conductive electrodes

Abstract

In this study, high-aspect-ratio (~1250) curved copper nanowires (CuNWs) composed of formate (FA) as the surface passivation layer were synthesized by the solvothermal method using sodium formate (HCOONa). Experimental data and density functional theory (DFT) simulations suggest that the growth of CuNWs-FA was due to the high chemisorption energy of FA on the [100] plane of Cu. The relative resistance ratio of CuNWs-FA increased by 1.67 and 1.72 after aging at 25 °C for 60 days and 60 °C for 5 days, showing FA passivation greatly improved the oxidation resistance of CuNWs. The transparent conductive electrodes (TCEs) fabricated from CuNWs-FA showed high transmittance (89.19%), low sheet resistance (Rs = 44.54 Ω sq−1), and excellent mechanical stability against 10,000 bending cycles. The TCEs-based transparent flexible heaters (TFHs) exerted a fast heating rate and a uniform temperature distribution within the 20 s response time, which is a testament to the CuNWs-FA in applications such as electrochromic and optoelectronic devices. This passivation approach sheds light on solving the major drawback of CuNWs oxidation and promotes its use in flexible electronic devices.