An insight to the point-active graphene writing in the aqueous graphite oxide solution
Cheng-Hao Chuang1*, Yu-Xun Chen1, Chien-Ming Chen1, Hsin-Yu Chen1, Lo-Yueh Cheng2, Chia-Hao Chen3
1Department of Physics, Tamkang University, New taipei city, Taiwan
2Department of Physics, National Tsin-Hua University, Hsinchu, Taiwan
3National Synchrotron Radiation Research Center, Hsinchu, Taiwan
* presenting author:Cheng-Hao Chuang,
A single-layer graphene demonstrates the fast carrier mobility, good bio-compatibility, robust structure and chemical stability for the next-generation electronics materials, while the quasi-relativistic particles at Dirac point and strongest interatomic C=C bond are representative of the novel electronic and chemical strucutres. Since it is highly desirable for the ability to add, remove, and modify graphene in a rapid and flexible way, writing graphene directly is becoming a pretty challenge as to enable the graphene-related electronics functionalized. On the other hand, individual graphene sheet is exfolizted and repulsed by the surface stabilizers during the chemical oxdiation process. The well-dispersed colloids of graphene oxide (GO) are solvable in the aqueous solution by the hydrophic property of the carboxylic acid and hydroxyl groups. Here, the combinaiton of graphene synthesis and writing on the metallic substrate becomes possible by the use of scanning electrochemical microscopy (SECM) technology. The GO sheets are converted to the reduced graphene oxide (rGO) owing to the negative-potnetial reduction and proton ion reaction occurred at the interface of working electrode. The written line is about 30 μm width and 500 μm length, depending on the radius scale and moving distance of Pt tip in SECM. The interdistance (between the tip and sunstrate) can modulate the surface morphology with the superposition effect. The control of bias potential and pH value makes the ionization degree of functional group and surface charge potential variable in the rGO solidization, as to the electrostatic force and diffusion movement between colloidal particles. Besides, the sheet conjunction, sp2-domain fabrication, and de-oxidation effect are visualized by the element-resolved and site-specific electronic structure analysis in scanning photoelectron microscopy, which is corresponding to the Raman and scanning electron microscopy analysis. New achievements in the writing deposition and probing platforms are available for further graphene-related advancement and expansibility in the wet environment.

Keywords: Graphene oxide, Scanning Electrochemical Microscopy, Graphene, Raman microscopy