Lecture,Central South University
High Conductive Graphene Inks for Flexible Printed Electronics
Pei He (1, 2*), Jianyun Cao (2), Hui Ding (2), Chongguang Liu (2), Ian A. Kinloch (2), and Brian Derby (2) (1) School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China. (2) School of Materials, University of Manchester, Oxford Road, M13 9PL, U.K. The development of high conductivity inks is critical to the progress of printed electronics [1, 2]. A promising conductive ink should fulfil high conductivity, long time stability, low cost, and compatibility with a range of substrates. For flexible applications, the printed conductive patterns also need good resistance to flexure and ability to withstand some extensional strain. Graphene, a two-dimensional allotrope of carbon, is a promising material for producing of conductive ink due to its high conductivity, good mechanical properties, and high-throughput production ability by solution processing. Graphene-based inks can be deposited to form conductive patterns through inkjet printing, gravure printing, and screen printing techniques. Here, a highly conductive ink based on graphene nanoplatelets is described. The graphene ink can be easily printed on flexible substrates using screen printing. After post-printing annealing and a rolling compression treatment, the printed graphene patterns exhibit a high conductivity of 8.81 × 104 S m-1. These graphene patterns have been printed on plastic and paper substrates and show good flexibility. As a demonstrator we have fabricated a metallic current collector-free solid-state supercapacitor by using the printed graphene as the current collector and printed activated carbon as the active material with a 1 M H3PO4/polyvinyl alcohol (PVA) gel as the electrolyte. The supercapacitor shows an area capacitance of ~ 40 mF cm-2 and good rate capability. Furthermore, combined with inkjet-printed graphene oxide as the sensor layer, the graphene tracks are exploited as the electrodes for fully printed humidity sensors on paper-based substrates, which shows fast responsibility and good recycle stability. This work provides a compelling route for the application of graphene-based materials for scalable fabricating of low cost and flexible printed electronics.  B. Derby, Annual Review of Materials Research, 40, 395-414 (2010).  S. P. Chen, H. L. Chiu, P. H. Wang, Y. C. Liao, Ecs J Solid State Sc, 4, (2015).
Dr. Pei He obtained his B.S. at Xidian University and M.Eng. degrees at Shanghai Jiao Tong University in China in 2009 and 2012, respectively, and completed his Ph.D. with Prof. Brian Derby at University of Manchester in UK in 2016. He joined the National Graphene Institute at University of Manchester as a Research Associate from December 2016 to December 2017. He joined the School of Physics and Electronics in Central South University as a Lecturer in March 2018. His research is focused on the preparation of functional inks based on two dimensional materials, printing of electronic devices based on 2D materials, and optimization of device structure and interface engineering during the printing process.
Central South University (CSU) is situated in Changsha, a famous historical and cultural city in Hunan, China, and covers an area of 3,924,000 m2 (with a floor area of 2,760,000 m2), with its campuses distributed on the east and west of Xiangjiang River. Backed by the majestic Yuelu Mountain and facing the grand Xiangjiang River, CSU has pleasing scenery and is ideal for study and research.