Yunyu Joseph Han

I have fulfilled three projects granted by NSERC. One was in the study of bioelectrochemical sensors for HCG and cTnI, which potentially leads to portable devices for health control. Another research is on NanoAOP of wastewater by ozonation and hydrogen peroxide. The results betoken wastewater treatment devices. The other research was on the synthesis of Au nanoparticles electrochemically.  The produced Au nanoparticles can be widely used in lab research and industrial production.

    In the process of completing doctoral degree, I have investigated the fabrication and modification of metal nanostructures by electrodeposition. The linear potential sweep voltammograms and cyclic voltammograms reveal the effects of additives on the electrochemical process of metal thin film and nanoparticles. In situ scanning tunneling microscopy provides us with the kinetics of nucleation and growth of metal nanostructure films. The research emphasizes the nanoparticles’ shape orientation tailored by the addition of organic molecules. Atomic force microscopy images show that trigonal and square pyramidal nanoparticles are formed on the metal surface by electrochemical deposition. These results are used to control the fabrication of nanostructure and to modify a metal electrode surface. The shape controlled nano-arrays are potentially used as nanoelectrode and plasmon. The nonlinear optical second harmonic generation and computational simulation both reinforce that the interaction between additive molecules and substrate plays an important role in fabricating a certain shape of nanoparticles, which is now widely used in catalytic chemistry and biochemistry.

             In my early research of photovoltaic electrochemistry, biochemical material chlorophyll-a from botanical leaves is used as the pigment in solar cells.  The research imitates the function of chlorophyll-a as an antenna to receive the solar energy in live plant cells. The photovoltaic cell is assembled with chlorophyll-a, polyvinyl alcohol, and transparent electrodes. The characteristic parameters of the solar battery have been reported in a series of papers, which have made a significant contribution to the organic solar cells. The importance of the research is both to make solar cells and to learn the way the chlorophyll-a functions in vivo.