| Summary: | The goal of this master’s thesis was to identify a suitable material that can be used as a flexible
substrate for implantable graphene devices. The literature section introduces the characteristics
of graphene and graphene oxide, followed by an overview of their production, transfer methods,
and optical modification. Subsequently, potential materials that could facilitate the purpose
were analyzed, eventually resulting in the selection of PDMS, which appeared to be a suitable
candidate for further investigation.
Experimental work focused on developing a novel method to employ PDMS as a functional
substrate, including a PMMA-free transfer of CVD graphene. The success of the process and
the quality of the graphene were affirmed by AFM and Raman spectroscopy, which indicated
the presence of high-quality single-layer graphene on PDMS by the high I2D/ IG ratio. The
preservation of graphene on PDMS during laser exposure demonstrated its stability and
behaviour comparable to graphene on SiO₂, reinforcing its potential for flexible electronics.
Functionalized graphene was characterized using Raman spectroscopy and AFM, revealing
structural and mechanical changes. While height modifications remained minimal, higher doses
influenced adhesion, indentation, and dissipation energy. Raman mapping confirmed that defect
induction correlated with pulse energy and exposure time. Graphene remained largely intact
with modest defects, likely within the point defect regime. The 2D band response suggested a
resonance shift due to altered interactions between graphene and PDMS. Lower pulse energy
doses appeared to clean the graphene surface, whereas, beyond a threshold, the two-photon
oxidation (2PO) process dominated. These findings underscore the viability of PDMS as a
functional, flexible substrate for graphene, paving the way for advancements in implantable and
flexible electronic devices.
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