Micro-/nano-voids guided two-stage film cracking on bioinspired assemblies for high-performance electronics

• Published in: Nature communications Vol. 10; no. 1; pp. 3862 - 8
• Main Authors: Miao, Weining, Yao, Yuxing, Zhang, Zhiwei, Ma, Chunping, Li, Shengzhe, Tang, Jiayue, Liu, He, Liu, Zemin, Wang, Dianyu, Camburn, Michael A., Fang, Jen-Chun, Hao, Ruiran, Fang, Xinyu, Zheng, Shuang, Hu, Nan, Wang, Xiaoguang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27.08.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/146; 147/135; 147/3; 639/301/1005; 639/301/1023/303; 639/301/119/544; Acoustics; Cochlea; Crack propagation; Cracks; Electronics; External stimuli; Humanities and Social Sciences; multidisciplinary; Nanotechnology; Nanowires; Science; Science (multidisciplinary); Strain; Stretchability; Voids
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-11803-8

Current metal film-based electronics, while sensitive to external stretching, typically fail via uncontrolled cracking under a relatively small strain (~30%), which restricts their practical applications. To address this, here we report a design approach inspired by the stereocilia bundles of a cochlea that uses a hierarchical assembly of interfacial nanowires to retard penetrating cracking. This structured surface outperforms its flat counterparts in stretchability (130% versus 30% tolerable strain) and maintains high sensitivity (minimum detection of 0.005% strain) in response to external stimuli such as sounds and mechanical forces. The enlarged stretchability is attributed to the two-stage cracking process induced by the synergy of micro-voids and nano-voids. In-situ observation confirms that at low strains micro-voids between nanowire clusters guide the process of crack growth, whereas at large strains new cracks are randomly initiated from nano-voids among individual nanowires. Metal film-based electronics usually fail via uncontrolled cracking at small strains. Here, the authors design a micro-/nano-structured surface with bundled flexible nanowires onto which a metal film can stretch more than a regular flat surface, retard penetrating cracks and remain sensitive.