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

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 highresolution 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 lowtemperature and 3D approach enables miniaturization of flexible electrical circuits down to 1 ?m 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.

Automated summary

In this study, a novel additive manufacturing approach using surface-activation-localized electroless plating (SALEP) was reported for selectively depositing high-resolution multi-metal layers and fabricating high-performance electronic devices for flexible electronics. The SALEP approach allows for layer-by-layer deposition of multi-metal patterns without the need for subtractive lithography, enabling the fabrication of OTFT arrays with high hole mobility. This low-cost and scalable method offers a promising solution for the development of high-performance flexible electronic devices.