Direct fabrication of high-resolution and high-performance flexible electronics via surface-activation-localized electroless plating

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-07, Vol.416, p.127644, Article 127644
• Main Authors: Li, Wanli, Li, Lingying, Sun, Qingqing, Liu, Xuying, Kanehara, Masayuki, Nakayama, Tomonobu, Jiu, Jinting, Sakamoto, Kenji, Minari, Takeo
• Format: Article
• Language: English
• Subjects: 3D interconnections; Additive manufacturing; Electroless plating; Flexible multi-metal patterns; Organic thin-film transistors; Patterning
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.127644

[Display omitted] •Surface-activation-localized electroless plating enables high resolution electronics.•1 µm resolution multi-metal patterns are realized on various flexible substrates.•Multilayer flexible 3D interconnections are fabricated with tailored functions.•Large-area transistor arrays are fabricated with high performance and flexibility. Patterning high-resolution multi-metal layers without using subtractive lithography poses a substantial challenge but is indispensable for the development of the modern electronics industry, especially flexible electronics. Herein, the general and feasible additive manufacturing approach is reported to selectively deposit high-resolution multi-metal patterns via surface-activation-localized electroless plating (SALEP) and enable the fabrication of 3-dimensional (3D) interconnections and high-performance organic thin-film transistor (OTFT) arrays for flexible electronics. The SALEP approach comprises the direct layer-by-layer deposition of multi-metal patterns interconnected by via holes, which are defined by the selective adsorption of palladium catalysts and a metallization process. The localized adsorption of the catalyst is guided by the difference in surface wettability and adsorbability caused by vacuum ultraviolet (VUV)-induced photochemical modification. The low-temperature and 3D approach enables miniaturization of flexible electrical circuits down to 1 µm in width; it also enables integration of an OTFT array on a flexible substrate. The fabricated OTFT array with multi-metal Cu/Ni/Au as contact electrodes exhibits a high hole mobility exceeding 10 cm2 V−1 s−1, demonstrating the adaptability of the SALEP approach for the low-cost, high-efficiency, and scalable fabrication of high-performance flexible electronic devices.