Highly Stable Copper\nNanowire-Based Transparent Conducting\nElectrode Utilizing Polyimide as a Protective Layer

Abstract

We report the significant improvement of the stability\nof a copper\nnanowire (Cu NW)-based transparent conducting electrode (TCE). Our\nstudy confirms that in contrast to the common use of poly(vinyl pyrrolidone)\n(PVP) as a surface passivation agent, PVP facilitates the surface\noxidation of CuNWs, which, in turn, severely affects the stability\nand performance of TCEs. To mitigate this issue, polyimide (CPI) is\nused as a protective layer for the fabrication of the Cu NW TCEs in\nthe absence of PVP, which shows exceptional stability. The conductivity\n(resistivity) measurement confirms the stability of TCEs over a period\nof 90 days without any major degradation, while the conductivity of\nthe reference TCE degrades completely after ∼15 days. In addition,\nwe also demonstrate the device application of our Cu NW TCEs by fabricating\na thin-film transistor (TFT) and an organic solar cell showing good\noperational stability. This study provides an insight into the role\nof PVP in the poor stability of Cu NWs and offers an alternative for\nthe fabrication of Cu NW-based TCEs with improved stability.