Overcoming Temperature‐Induced Degradation of Silver Nanowire Electrodes by an Ag@SnO_x Core‐Shell Approach

Abstract

diodes, [3] electromagnetic shielding, [4] and organic photovoltaics. [5] Electrodes based on metallic nanowires (NWs) are among the most promising alternatives to indium tin oxide (ITO), which is currently the most efficient and widely used transparent conducting material. [6] Silver, the metal with the highest electrical conductivity, can be expected to provide the best network electrodes. [7] Indeed, silver nanowires (Ag NWs)-based percolating networks successfully combine high flexibility, high optical transparency, and high electrical conductivity. [8] Ag NWs electrode are also cost-efficient and compatible with large-scale manufacturing methods. [5a] However, they are very vulnerable to heat, light, oxygen, humidity, and sulfidation, limiting their usefulness for practical applications. [9] Solutions to these problems have been investigated and various methods were applied to protect the Ag NWs. [10] Recently, a SnO x shell was proposed as a solution to overcome the stability issues. [11] Zhao et al. reported the wet chemical synthesis of Ag NWs with a monolayer of SnO 2 under ambient conditions. [11a] This is achieved by introducing trace amounts of Sn 2+ to an Ag NWs dispersion, which form an oxide monolayer. This Transparent electrodes consisting of silver nanowires (Ag NWs) are a solution-processed alternative to commonly used indium tin oxide electrodes. Here, Ag NW electrodes protected by a tin oxide (SnO x ) are explored and unprecedented thermal stability is found. While unprotected Ag NW electrodes fail at 250 °C, the SnO x Ag NW electrodes remain stable for 40 h at 250 °C and withstand high temperatures up to 500 °C for short times. First, an optimized method of synthesis that provides uniform Ag NWs with high reproducibility is used. Afterward, a SnO x shell is formed in a wet chemical reaction. Fabrication of highly conductive electrodes requires thermal annealing at 300 °C for 5 min under ambient atmosphere. Electrodes with a sheet resistance as low as 20 Ω sq -1 and visible transmittance of 84% are demonstrated. It is shown that a ≈2 nm thick SnO x shell effectively protects the Ag NWs in a temperature range between 200 and 500 °C, whereas unprotected Ag NWs suddenly fail at temperatures beyond 200 °C. It is strongly anticipated that these improvements in the stability of Ag NWs open a large field of further investigations and applications.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/aelm.202100787.

Flexible Transparent Conductive Films of Ag/Cr2O3 Core–Shell Nanowires as Electrodes for Electroluminescent Devices and Heaters

“…The Ag/Cr 2 O 3 NW networks had higher FoM values than Cu nanowire-based ,, TCFs. The optoelectronic characteristics of Ag/Cr 2 O 3 NW networks in this study also compare favorably with some previously reported composite TCFs based on Ag NWs. ,− Although the FoM of some Ag NWs networks that have been compounded with oxides is higher, the preparation of these networks is time-consuming and expensive. − Their widespread use in real-world production is restricted by their expensive price. In contrast, the all-solution method used in this study to grow dense Cr 2 O 3 protective layers on the surface of Ag NWs allows for the growth of these layers under nonvacuum room temperature conditions, lowering processing costs and times, enhancing silver nanowire stability in harsh environments, and obtaining superior optoelectronic performances.…”

SnO2-Coated Silver Nanowire Networks as a Physical Model Describing Their Reversible Domain under Electrical Stress for Stable Transparent Electrode Applications

“…Previously reported works on SnO 2 /AgNW nanocomposites show a clear enhancement of thermal and/or chemical stability of AgNW networks. − In these studies, chemical vapor deposition and sputtering methods were used to deposit SnO x layers on AgNW networks. None of them have used AP-SALD, except one of our previous work .…”

“…This sometimes happens at the expense of performance, leading to lower transmittance, larger electrical resistance or decrease in flexibility . The investigated coatings are often thin layers of metal oxides such as zinc oxide (ZnO), titanium oxide (TiO 2 ), metal oxynitrides (AlO x N y ), or tin oxide (SnO 2 ). − In all of these studies, a clear improvement in the stability of the AgNW networks, as well as AgNW adhesion to the substrate, is often reported, thanks to oxide coatings . These coatings are often deposited by spin-coating or by vacuum-based techniques such as atomic layer deposition (ALD) or sputtering and very often exhibit scalability issues for AgNW-based TEs.…”

“…To the best of our knowledge, only a few recent articles report AgNW networks coated with tin oxide (SnO 2 ) − and none of them were fabricated by AP-SALD except one of our previous work . The SnO 2 -coated AgNW networks are here after named SnO 2 /AgNW networks.…”

Exploring the degradation of silver nanowire networks under thermal stress by coupling in situ X-ray diffraction and electrical resistance measurements

“…9 However, SnO 2 /AgNW nanocomposites have only been investigated in a few recent articles. 15,[17][18][19][20][21] Several studies have been devoted to investigating the structural properties of AgNWs using X-Ray Diffraction (XRD) measurements under ambient conditions. XRD is a powerful and non-destructive method for studying nanomaterials, 22 particularly during in situ experiments.…”