Kim Jongyoun, Hwang Inkook, Kim Minkyoung, Jung Hyeonwoo, Bae Hyejeong, Lee Youngu
Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungang-daero, Hyeonpung-Eup, Dalseong-Gun, Daegu 42988, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Feb 2;14(4):5807-5814. doi: 10.1021/acsami.1c21223. Epub 2022 Jan 18.
Copper nanowires (CuNWs) possess key characteristics for realizing flexible transparent electronics. High-quality CuNW micropatterns with high resolution and uniform thickness are required to realize integrated transparent electronic devices. However, patterning high-aspect-ratio CuNWs is challenging because of their long length, exceeding the target pattern dimension. This work reports a novel reverse-offset printing technology that enables the sub-10 μm high-resolution micropatterning of CuNW transparent conducting electrodes (TCEs). The CuNW ink for reverse-offset printing was formulated to control viscoelasticity, cohesive force, and adhesion by adjusting the ligands, solvents, surface energy modifiers, and leveling additives. An inexpensive commercial adhesive handroller achieved a simple, fast, and scalable micropatterning of CuNW TCEs. Easy production of high-quality CuNW micropatterns with various curvatures and shapes was possible, regardless of the printing direction. The reverse-offset-printed CuNW micropatterns exhibited a minimum of 7 μm line width and excellent pattern qualities such as fine line spacing, sharp edge definition, and outstanding pattern uniformity. In addition, they exhibited excellent sheet resistance, high optical transparency, outstanding mechanical durability, and long-term stability. Flexible light-emitting diode (LED) circuits, transparent heaters, and organic LEDs (OLEDs) can be fabricated using high-resolution reverse-offset-printed CuNW micropatterns for applications in flexible transparent electronic devices.
铜纳米线（CuNWs）具备实现柔性透明电子器件的关键特性。要实现集成透明电子器件，需要高质量、高分辨率且厚度均匀的CuNW微图案。然而，对高纵横比的CuNWs进行图案化具有挑战性，因为它们的长度较长，超过了目标图案尺寸。本文报道了一种新颖的反向胶版印刷技术，该技术能够对CuNW透明导电电极（TCEs）进行亚10μm的高分辨率微图案化。通过调整配体、溶剂、表面能改性剂和流平添加剂，配制了用于反向胶版印刷的CuNW油墨，以控制其粘弹性、内聚力和附着力。一种廉价的商用粘性手辊实现了CuNW TCEs的简单、快速且可扩展的微图案化。无论印刷方向如何，都能够轻松生产出具有各种曲率和形状的高质量CuNW微图案。反向胶版印刷的CuNW微图案的线宽最小为7μm，并且具有诸如精细的线间距、清晰的边缘定义和出色的图案均匀性等优异的图案质量。此外，它们还表现出优异的方块电阻、高光学透明度、出色的机械耐久性和长期稳定性。使用高分辨率反向胶版印刷的CuNW微图案可以制造柔性发光二极管（LED）电路、透明加热器和有机发光二极管（OLED），用于柔性透明电子器件。
