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Flexible electronic circuitry is an emerging technology that will significantly impact the future of healthcare and
medicine, food safety inspection, environmental monitoring, and public security. Recent advances in drop-on-demand
printing technology and electrically conductive inks have enabled simple electronic circuits to be fabricated on
mechanically flexible polymers, paper, and bioresorbable silk. Research has shown that graphene, and its derivative
formulations, can be used to create low-cost electrically conductive inks. Graphene is a one atom thick two-dimensional
layer composed of carbon atoms arranged in a hexagonal lattice forming a material with very high fracture strength, high
Young’s Modulus, and low electrical resistance. Non-conductive graphene-oxide (GO) inks can also be synthesized
from inexpensive graphite powders. Once deposited on the flexible substrate the electrical conductivity of the printed
GO microcircuit traces can be restored through thermal reduction. In this paper, a femtosecond laser with a wavelength
of 775nm and pulse width of 120fs is used to transform the non-conductive printed GO film into electrically conductive
oxygen reduced graphene-oxide (rGO) passive electronic components by the process of laser assisted thermal reduction.
The heat affected zone produced during the process was minimized because of the femtosecond pulsed laser. The degree
of conductivity exhibited by the microstructure is directly related to the laser power level and exposure time. Although
rGO films have higher resistances than pristine graphene, the ability to inkjet print capacitive elements and modify local
resistive properties provides for a new method of fabricating sensor microcircuits on a variety of substrate surfaces.
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