EH Yang Research Group
Our group investigates and utilizes surface properties of 1D/2D atomic layers and conjugated polymers for sensing and energy applications. Our current research interests revolve around two distinct, but intersecting, areas:
We investigate tunable wetting of conjugated polymer surfaces for microfluidics, energy/environment, and biomedical devices. For the purpose of manipulating liquid droplets at ultra-low voltages (~1.5V), we demonstrate the tunable wetting mechanism on a smart polymer: dodecylbenzenesulfonate-doped polypyrrole (PPy(DBS)), and probe fundamental mechanisms related to the electrochemical transport and reversible wetting states of PPy(DBS) upon continuous reduction and oxidation reactions. Ultimately, this project is expected to enable the development of lab-on-a-chip (LOC) devices which can bi-directionally transport liquid droplets at voltages which are of much lower orders of magnitude than existing techniques. In addition to the LOC applications, we are currently looking into other applications including chemical separation and antimicrobial devices based on engineered PPy surfaces.
We explore 1D and 2D atomic layers to enable tunability of several material properties with applications to detectors. In our recent work in collaboration with Prof. Strauf group (Physics), we showed evidence of a dominant photoelectric effect in fully suspended CVD-grown graphene microribbons. This is a promising step towards wafer-scale fabrication of graphene photodetector devices approaching terahertz cut-off frequencies with efficiencies similar to bolometers- but at a much higher speed. Further, we work on elucidating fundamental mechanisms related tophotoconductivity. We also explore the energy storage applications of graphene, 2D dichalcogenides and carbon nanotube architectures. In addition, we study the growth domain of graphene, showing that the underlying Cu surface orientation has a major influence on the growth kinetics from nucleation to diffusion- an important finding towards tailoring properties of graphene as well as other 2D dichalcogenides via substrate engineering.