UV-converted heterogeneous wettability surface for the realization of printed micro-scale conductive circuits

• Published in: Flexible and printed electronics Vol. 8; no. 3; pp. 35019 - 35028
• Main Authors: Shui, Ke, Fang, Yuxiao, Li, Zerui, Wang, Zhenguo, Jiang, Subin, Yin, Ni, Chen, Qi, Guo, Feng-Qi, Zhao, Jian-Wen, Lin, Jian, Ma, Chang-Qi
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.09.2023
• Subjects: heterogeneous wettability surface; precision circuit; spontaneous patterning; UV response
• ISSN: 2058-8585; 2058-8585
• DOI: 10.1088/2058-8585/acf772

Abstract Achieving high precision in the fabrication of electronic circuits through additive manufacturing requires breaking the resolution limit of traditional printing processes. To address this challenge, we have developed a novel approach that involves preparing a heterogeneous wetting surface using a light-sensitive NBE-acrylate resin. By creating differences in surface energy on the substrate, we can limit the spread of the ink and surpass the limitations of conventional processes, achieving a printing resolution of 5 μ m. The NBE-acrylate resin can be cross-linked under white LED light illumination (with λ > 400 nm) to yield a hydrophobic surface, which can be converted to a hydrophilic surface by UV light illumination ( λ = 254 nm). The photochemical reaction of the NBE-acrylate resin under different light irradiation was confirmed by Fourier transform infrared spectroscopy (FTIR) and atomic force microscope (AFM) microforce measurements. In combination with a photomask, patterned heterogeneous wettability surfaces were prepared, which can be utilized for printing precision electronic circuits. Micrometer-scale printed circuits with a low line-to-space (L/S) of 5/50 and 10/10 μ m were successfully achieved by optimizing the ink formulation, which is significantly beyond the printing resolution. In the end, fully printed thin film transistor arrays based on semi-conducting carbon nanotubes were achieved, which showed higher charge carrier mobilities of 1.89–4.31 cm 2 s −1 V −1 depending on the channel width, demonstrating the application of this precision printed technique.