| dc.description.abstract | Graphene, which has exceptional electrical, mechanical, transparency and chemical stability properties, has potential to be applied to flexible electronic and optoelectronic device. Using Chemical Vapor Deposition (CVD) to synthesize graphene film on transition metals is the main method for producing large area, highly crystalline, and uniform graphene film. However, transferring large area graphene films is still a critical issue for graphene applying in industrial-scale production.
In this research, we use CVD to synthesize large area and high-performance multilayer graphene films. Furthermore, we invest the dry transfer method to transfer graphene films on a flexible substrate in order to develop high-performance flexible substrate which can be applied to high transparency, high chemical stability, temperature resistant and flexible electrical conductive film.
Results of this research are as follows. (1) Directly synthesize 2~3 uniform multilayer graphene that is highly crystalline (ID/IG ≈ 0.12) and high optoelectronic performance (Rs: 800 ohm/sq, at 550 nm T: 94%). (2) Using Roll to Roll Mechanical Exfoliation method (R2RME) to transfer graphene films onto different flexible substrates. Combining the optimized conditions (tension and tear angle, etc.) of R2RME and Electrochemical can increase the yield, uniformity, and conductivity of graphene films. (3) Doping graphene films that have been transferred onto flexible substrates. We use different kinds of chemical doping methods to modify graphene films and discuss how they make influences on sheet resistance. Following are the results of this work. (i) The sheet resistance and transmittance of the single layer graphene film can reach 57 ohm/sq and 94%, respectively. (ii) Combining EC-DME dry transfer method with chemical doping can make the sheet resistance decrease to ~290 ohm/sq , transmittance ~85% (including the substrate)
In summary, with different kinds of binder developed in this research, we can directly exfoliate graphene films from Cu foil and retain the properties of the conductive film. This is an industrial-scale production dry transfer method, which can lower the cost of production and is eco-friendly.
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