Song Tze-Bin, Rim You Seung, Liu Fengmin, Bob Brion, Ye Shenglin, Hsieh Yao-Tsung, Yang Yang
Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
California NanoSystems Institute, University of California-Los Angeles , Los Angeles, California 90095, United States.
ACS Appl Mater Interfaces. 2015 Nov 11;7(44):24601-7. doi: 10.1021/acsami.5b06540. Epub 2015 Oct 29.
Solution-processed silver nanowire networks are one of the promising candidates to replace a traditional indium tin oxide as next-generation transparent and flexible electrodes due to their ease of processing, moderate flexibility, high transparency, and low sheet resistance. To date, however, high stability of the nanowire networks remains a major challenge because the long-term usages of these electrodes are limited by their poor thermal and chemical stabilities. Existing methods for addressing this challenge mainly focus on protecting the nanowire network with additional layers that require vacuum processes, which can lead to an increment in manufacturing cost. Here, we report a straightforward strategy of a sol-gel processing as a fast and robust way to improve the stabilities of silver nanowires. Compared with reported nanoparticles embedded in nanowire networks, better thermal and chemical stabilities are achieved via sol-gel coating of TiO2 over the silver nanowire networks. The conformal surface coverage suppressed surface diffusion of silver atoms and prevented chemical corrosion from the environment. These results highlight the important role of the functional layer in providing better thermal and chemical stabilities along with improved electrical properties and mechanical robustness. The silver nanowire/TiO2 composite electrodes were applied as the source and drain electrodes for In2O3 thin-film transistors (TFTs) and the devices exhibited improved electrical performance annealed at 300 °C without the degradation of the electrodes. These key findings not only demonstrated a general and effective method to improve the thermal and chemical stabilities of metal nanowire networks but also provided a basic guideline toward rational design of highly efficient and robust composite electrodes.
溶液法制备的银纳米线网络是有望取代传统氧化铟锡作为下一代透明柔性电极的候选材料之一，因其易于加工、适度的柔韧性、高透明度和低表面电阻。然而，迄今为止，纳米线网络的高稳定性仍然是一个主要挑战，因为这些电极的长期使用受到其较差的热稳定性和化学稳定性的限制。解决这一挑战的现有方法主要集中在用需要真空工艺的附加层来保护纳米线网络，这可能会导致制造成本增加。在此，我们报告了一种溶胶 - 凝胶工艺的直接策略，作为提高银纳米线稳定性的快速且稳健的方法。与报道的嵌入纳米线网络中的纳米颗粒相比，通过在银纳米线网络上溶胶 - 凝胶涂覆二氧化钛可实现更好的热稳定性和化学稳定性。保形的表面覆盖抑制了银原子的表面扩散，并防止了来自环境的化学腐蚀。这些结果突出了功能层在提供更好的热稳定性和化学稳定性以及改善电学性能和机械强度方面的重要作用。银纳米线/二氧化钛复合电极被用作氧化铟锡薄膜晶体管（TFT）的源极和漏极，并且这些器件在300℃退火时表现出改善的电学性能，而电极没有退化。这些关键发现不仅证明了一种提高金属纳米线网络热稳定性和化学稳定性的通用有效方法，而且为合理设计高效且稳健的复合电极提供了基本指导方针。
