Dry Printing Pure Copper with High Conductivity and Adhesion for Flexible Electronics

Journal Article · Tue May 14 00:00:00 EDT 2024 · ACS Applied Electronic Materials

DOI:https://doi.org/10.1021/acsaelm.4c00640· OSTI ID:2438825

Ahmadi, Zabihollah ^[1]; Patel, Aarsh ^[1]; Hill, Curtis ^[2]; Peeples, Steven R. ^[2]; Jones, Jennifer M. ^[2]; Boebinger, Matthew G. ^[3]; Mahjouri-Samani, Masoud ^[1]

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1. Auburn Univ., AL (United States)
2. NASA Marshall Space Flight Center (MSFC), Huntsville, AL (United States)
3. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)

Additive manufacturing of functional devices on various rigid and flexible substrates is rising rapidly due to their design flexibility, rapid manufacturing, and lower cost. Current printing technologies are ink-based and focused on printing silver (Ag) as conductive lines due to its matured ink formulation process, low sintering temperature, ease of printing, and low oxidation rate. However, Ag is the 68th most abundant element on Earth, while copper (Cu) is the 25th, making it much cheaper (>100×) while having a comparable conductivity to Ag. Therefore, printing Cu has become technologically and economically more attractive than Ag. Nevertheless, Cu printing is still a significant challenge in ink-based printing methods due to the higher sintering temperature relative to the glass-transition temperature of most flexible substrates, the higher oxidation rate, the challenging ink formulation process, and ink stability concerns. Here, we demonstrate printing highly conductive Cu on flexible polyimide substrates using a dry printing technique. Cu nanoparticles (~3–30 nm) are generated by on-demand laser ablation of a solid Cu target inside the printer head and under argon background gas. These Cu nanoparticles are then transported through a nozzle and onto the substrate, where they are laser-sintered in real time. The argon gas plays three critical roles in laser plume condensation for nanoparticle generation, transport, and sheath gas to avoid oxidation during sintering. The sintered nanoparticles thus show high electrical conductivity and mechanical stability under static and cyclic tests. Our dry printing technique can potentially revolutionize how electronic devices and sensors are additively manufactured for earth and space applications.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: National Aeronautics and Space Administration (NASA); USDOE Office of Science (SC)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2438825
• Journal Information: ACS Applied Electronic Materials, Journal Name: ACS Applied Electronic Materials Journal Issue: 5 Vol. 6; ISSN 2637-6113
• Publisher: ACS Publications
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Additive nanomanufacturing
Copper printing
Flexible electronics
Ink-free printing
Lasers
Layers
Nanoparticles
Printed electronics
Sintering
Surface interactions