Prof. Yihui Zhang’s group and his collaborators published a cover feature article in Nature Reviews Materials

Recently, an international team led by Yihui Zhang, an Associate professor from School of Aerospace Engineering at Tsinghua University, John A. Rogers, Louis Simpson and Kimberly Querrey Professor at Northwestern University, and Yonggang Huang, Walter P. Murphy Professor at Northwestern University, published a review paper in Nature Reviews Materials. This focusing review, entitled “Printing, folding and assembly methods for forming 3D mesostructures in advanced materials”, was selected as a cover feature article of Nature Reviews Materials in the 4th issue of 2017, which went live on April 5th.

The cover image of the 4th issue of Nature Reviews Materials in 2017

Complex 3D mesostructures widely exist in biological systems (e.g. cytoskeletal webs, neural circuits, vasculature networks), where they form naturally to provide essential functions in even the most basic forms of life. Analogous human-made 3D mesostructures have significant and widespread applications across a broad range of areas, such as biomedical devices, MEMS, optoelectronics, and metamaterials, representing a hot topic of scientific research for a long time. Existing approaches for forming 3D mesostructures are, however, constrained by a narrow range of applicable materials and 3D geometries. Especially, a long-standing, daunting challenge is in the development of approaches capable of building complex 3D structures of high-performance semiconductor materials (such as monocrystalline silicon). This affected the rapid development of 3D microelectronic devices.

In the past few years, an international team led by Prof. Yihui Zhang, Prof. John A. Rogers and Prof. Yonggang Huang developed a new method referred to as “mechanically guided assembly” for forming 3D mesostructures. They carried out a systematic research in the developments of design concepts, mechanics theories, assembly platforms and device applications. This method incorporated the concepts of buckling mechanics into the mature, planar fabrication technologies available in modern semiconductor industries, allowing well-controlled transformations of patterned 2D films into desired 3D structures by compressive forces. It enables rapid assembly of 3D mesostructures in a broad set of materials (e.g., semiconductor, metal, ceramic and polymer), over feature sizes from nanometer to decimeter dimensions. This study provides an innovative platform for the development of new 3D micro-devices in the fields of electronics, energy, biomedical engineering and optics. This series of achievements result from deep research collaborations among the groups of Prof. Yihui Zhang, Prof. Yonggang Huang and Prof. John A. Rogers. Since 2015, this international team has published several articles in high-impact journals, including Science (cover article), PNAS, and Science Advances, which have attracted widespread attention and media reports. In view of the contributions of this international team in the area of 3D micro-assembly, they have been invited by Nature Reviews Materials to write a focusing review paper regarding the various approaches for forming 3D mesostructures. This review summarizes the mainstream printing, folding and assembly methods in this area, and introduces the wide applications achieved with these methods. In particular, it highlights the latest progress and trends in the developments of relevant methods, and provides an overview on the challenges and opportunities.

Mechanically guided assembly for forming 3D structures in a broad set of materials over wide-ranging feature sizes

Prof. Yihui Zhang is the first author and a co-corresponding author of this review paper and Prof. John A. Rogers at Northwestern University is another co-corresponding author. Other authors of this review paper include Fan Zhang and Qiang Ma, both Ph.D. students from School of Aerospace Engineering at Tsinghua University, Dr. Zheng Yan and Prof. Xiuling Li at University of Illinois at Urbana-Champaign, and Prof. Yonggang Huang at Northwestern University. These studies received supports from the National Natural Science Foundation of China and Thousand Young Talents Program of China.