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Alternatives for PMMA for up-scalable CVD-graphene transfer

: Matis, Martin; Kosidlo, Urszula; Skakalova, Viera; Tonner, Friedemann; Glanz, Carsten; Kolaric, Ivica; Bauernhansl, Thomas

Galiotis, Costas (Chairman):
GrapHEL - A European Conference/Workshop on the Synthesis, Characterization and Applications of Graphene 2012 : 27-30 September 2012, Mykonos, Greece; Electronic Book of Abstracts
Patras, 2012
1 pp.
European Conference/Workshop on the Synthesis, Characterization and Applications of Graphene <2012, Mykonos>
Fraunhofer IPA ()
transparente Elektrode; chemical vapour deposition (CVD); Graphene; Polymerer Werkstoff; chemische Abscheidung; Werkstoff

The chemical vapor deposition (CVD) grown graphene is one of the most promising materials for flexible transparent electrodes mostly used in displays. The state of art synthesis of CVD graphene allows production of layers as large as 50x50 cm2 on copper substrate. In order to use them in displays, the transfer to transparent dielectric substrates is necessary. However, CVD graphene is damaged during transfer in the form of voids in graphene and residues of support layer. Therefore, the transfer of CVD-produced graphene is one of the major bottlenecks for its utilization in displays. The standard transfer technologies use poly (methyl methacrylate) (PMMA) in combination with acetone or isopropanol as solvents. Residues of PMMA after transfer on the final substrate represent a serious obstacle in transparent electrode utilization in displays, causing a lowered conductivity, poor adhesion and increasing surface roughness. Due to substantial bending and large tensile forces during handling in large scale production, the standard method is not up-scalable.
In order to improve and up-scale the transfer process, a readily soluble, flexible and mechanically strong support layer is needed. In this work polycarbonate (PC) and polystyrene (PS) is tested because of their mechanical strength, flexibility and better solubility in organic solvents in comparison with PMMA.
In the first place, the effect of temporary support polymer on the quality and purity of graphene has been investigated by means of Raman spectroscopy and scanning electron microscopy (SEM), followed by the measurements of electrical conductivity and optical transparency. Conclusions on up-scaling of graphene transfer techniques will be drawn from the results of PC and PS as substrate in comparison to PMMA.