Direct Laser Writing of PEDOT nanostructures

Description

In bioelectronics, creating nanostructures with high spatial precision and enhanced electrical properties
is crucial for advancing biomedical devices and sensors. Poly(3,4-ethylenedioxythiophene) (PEDOT),
a conductive polymer known for its excellent biocompatibility and electrical conductivity1, holds
significant promise in this field. Traditional methods for PEDOT fabrication, such as chemical or
electrochemical polymerization, lack the resolution required for nanoscale bioelectronic interfaces. To
address this limitation, we have applied a STED-inspired two-photon lithography (TPL) approach for
direct laser writing of PEDOT nanostructures, utilizing 7-diethylamino-3-thenoylcoumarin (DETC) as
a photoinitiator for EDOT photopolymerization.
TPL is highly effective at forming 3D structures in a single step, offering an advantage over the
traditional layer-by-layer method 2. It allows the use of low-energy near-infrared femtosecond laser
pulses to avoid damaging sensitive materials such as organic polymers and biomaterials. In
combination with super-resolution techniques, like stimulated emission depletion (STED) 3 or transient
absorption depletion (TAD) lithography 4, it becomes a powerful instrument for the nanopatterning of
soft materials.
Our current study demonstrates that DETC, conventionally used for radical photopolymerization, can
effectively initiate EDOT two-photon polymerization. Furthermore, we successfully applied their
blend in TAD lithography, achieving a 60% reduction in feature size compared to standard two-photon
lithography. Notably, the electrical conductivity of the resulting PEDOT structures was found to
correlate with carbon species production during the lithography process.

Period	Mar 2025
Event title	BioEl 2025
Event type	Conference
Degree of Recognition	International