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Transversally Extended Laser Plasmonic Welding for Oxidation-Free Copper Fabrication toward High-Fidelity Optoelectronics
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posted on 2016-05-31, 00:00 authored by Jung Hwan Park, Sunho Jeong, Eun Jung Lee, Sun Sook Lee, Jae Young Seok, Minyang Yang, Youngmin Choi, Bongchul KangLaser direct processing is a promising
approach for future flexible
electronics because it enables easy, rapid, scalable, and low-temperature
fabrication without using expensive equipment and toxic material.
However, its application for nanomaterials with high chemical susceptibility,
such as representatively Cu, is limited because severe oxidation occurs
under ambient conditions. Here, we report the methodology of a transversally
extended laser plasmonic welding
process, which outstandingly improves the electrical performance of
a Cu conductor (4.6 μΩ·cm) by involving the spatially
concurrent laser absorption to the surface oxide-free Cu nanoparticles
(NPs). Physical/chemical properties of fabricated Cu conductors are
fully analyzed in perspectives of the mechanism based on the thermo-physical-chemical
interactions between photon energy and pure Cu NPs. The resultant
Cu conductors showed an excellent durability in terms of bending and
adhesion. Furthermore, we successfully demonstrated a single layer
Cu-mesh-based touch screen panel (TSP) on thermally sensitive polymer
film as a breakthrough of typical metal oxide-based transparent touch
sensors. The Cu metal mesh exhibited high transmittance (95%) and
low sheet resistance (30 Ω/square). This self-capacitance type
and multitouchable TSP operated with a fast response, high sensitivity,
and durability.