Graphene-based composite for transparent electrode
Tsung-Chin Cheng1*, Cheng-Feng Yu1, Kuo-You Huang1, Ang-Sheng Chou1, Po-Han Chang1, Chao-Chen Chang1, Chih-I Wu1
1GIPO, National Taiwan University, Taipei, Taiwan
* presenting author:Tsung-Chin Cheng,
In this research, we demonstrate the graphene/copper composite film(G.C.C film) has high electrical and mechanical property with wetting effect improve surface on graphene. Using a simple in-situ CVD process of graphene/Cu composite film which is G.C.C film, followed by polymer-free transfer technique able to simultaneously reduce the sheet resistance to 100 ohm/sq corresponding to transmittance of 94% of double layered film, raise work function from 4.5eV to 4.8eV, improve mechanical strength, and improve wetting characteristics (contact angles from 85° to 53°) of solution process for fabricating organic optoelectronic devices. The wetting characteristic improvement for solution process can be attribute to increased portion of better wetting on copper islands/particles on graphene surface. The sheet resistance (Rsh) of graphene has been empirically verified with employing four mechanisms : (1) Enhancement with copper doping effect, (2) Increment of low resistance current paths, (3) Avoid PMMA-residue doping effect to increase Rsh, (4) No increase in density of states near Fermi level for valence band be observed.
The mechanical property improvement mechanisms is due to, copper islands/particles to be the bridging effect across domain boundaries and strengthening effect on domains.
Helpful for understanding electronic property in graphene/copper composite electrode material, these research results would be useful for future solution-based organic semiconductor processing for transparent and flexible optoelectronic device applications. It can be considered that further study of transparent & flexible electrode with different composite types, such as various layer structure, metal elements or alloys using utilizing our simple innovative CVD technology.

Keywords: Graphene, Chemical Vapor Deposition, Transparent electrode, Sheet resistance, composited