Abstract

Metal conductors are indispensable element for most future soft electronic devices that find remarkable applications in wearable displays and solar cells, deformable antenna and capacitors, electronic skins, point-of-care diagnostics, and biological actuators. One critical challenge in this field is how to fabricate highly conductive, adhesive, smooth, and soft metal conductors at low temperature under ambient conditions, and preferably in a roll-to-roll printable manner. Conventional metal nanoparticle inks fall short to satisfy these requirements because of their relatively high processing temperature, rough surface, and poor adhesion, especially for easily oxidized metals such as Cu.

Our laboratory recently develop Polymer-Assisted Metal Deposition (PAMD) to address this issue. PAMD allows ambient fabrication of flexible, foldable, stretchable, compressible, and wearable metal conductors with very high conductivity. The key innovation of PAMD is the use of a thin and functional polymeric interfacial layer that assists electroless deposition (ELD) of metal thin films and patterns (Au, Ag, Cu, and Ni) on soft substrates such as plastics, elastomers, papers, and polyurethane sponges. Such a polymer interfacial layer offers remarkable adhesion between metal and substrate, which is critical for enhancing the mechanical durability of the metal layer upon large deformation. Importantly, PAMD is compatible with versatile substrates and different printing technologies at ambient conditions. This seminar will discuss the materials chemistry of PAMD and demonstrate how to use PAMD for making high-performance flexible and wearable energy harvesting and storage devices.

Figure.    Polymer-assisted metal deposition (PAMD) and its various applications.

About the Speaker

Dr. Zijian Zheng is currently Associate Professor at the Institute of Textile and Clothing (ITC) at The Hong Kong Polytechnic University. His research interests include surface science, self-assembly, nanolithography, polymer science, and bendable/stretchable/wearable/graphene materials and electronic devices. He received his B. Eng. with honor from the Department of Chemical Engineering at Tsinghua University in 2003. Between 2004 and 2007, Dr. Zheng moved to the Department of Chemistry and Nanoscience Center at University of Cambridge for his PhD study under the supervision of Prof. Wilhelm T. S. Huck, where he worked on nanotechnology and organic optoelectronics. In 2008, Dr. Zheng joined the group of Prof. Chad A. Mirkin as a postdoctoral research fellow in the Department of Chemistry and International Institute for Nanotechnology at Northwestern University, working on the development of Dip-Pen Nanolithography and Polymer Pen Lithography. He joined ITC as Assistant Professor in 2009 and was promoted to tenured Associate Professor via a fast track in 2013. Dr. Zheng is known for his contribution to flexible and wearable materials and devices, and surface printing techniques. Dr. Zheng has published more than 70 papers in high-impact journals including Science, Nature Communications, Advanced Materials, Journal of the American Chemical Society, Angewandte Chemie, and Nano Letters. He also files 15 international and China patents. He serves as Guest Editor for Advanced Materials and Small. He is recipient of more than 10 academic awards such as Geneva Innovation Award (2015), Future Leaders Award (2015) and Early Career Award (2016).