In a groundbreaking development that could revolutionize the energy sector, researchers at the Institute of Innovative Mobility, Technische Hochschule Ingolstadt, have pioneered a new method for creating high-performance printed electronics. Led by Nihesh Mohan, the team has successfully demonstrated laser sintering of copper particle-free inks, opening doors to more efficient and cost-effective fabrication of flexible electronic devices.
Traditionally, sintering copper inks for printed electronics has required high temperatures and inert or reducing atmospheres, which can be damaging to low-melting substrates like Polyethylene Terephthalate (PET). Mohan and his team have circumvented this challenge by employing laser sintering, a technique that offers high-speed, localized heating. This innovation not only prevents substrate damage but also paves the way for more versatile and durable electronic components.
The study, published in the journal npj Flexible Electronics, explores the use of a copper formate tetrahydrate—amino-2-propanol complex ink. By optimizing laser parameters such as power, scan rate, and spot diameter, the researchers achieved a sintering process window suitable for two different flexible polymeric substrates: Polyimide and PET. “The key advantage of our method is the ability to precisely control the heating process, which allows us to work with a wider range of substrates without compromising performance,” Mohan explains.
The team’s experiments yielded impressive results, including a very low bulk resistivity of 3.24 µΩcm on trace thickness of 0.85 ± 0.15 µm. This resistivity is just 1.87 times that of bulk copper, demonstrating excellent electrical conductivity. The laser sintered traces also exhibited good adherence to polymeric substrates, a critical factor for the durability of flexible electronics.
One of the most exciting aspects of this research is its potential impact on the energy sector. Flexible printed electronics are increasingly being integrated into energy harvesting and storage devices, such as solar cells and batteries. The ability to create high-performance, low-cost electronic components on flexible substrates could lead to more efficient and versatile energy solutions. As Mohan notes, “Our method provides a promising pathway for the fabrication of low-cost and reliable flexible printed electronic devices, which could be game-changers in the energy sector.”
The research also explored different laser optic profiles, including Gaussian and top hat, to optimize the sintering process. Various methodologies for fabricating metallized copper layers were demonstrated, further highlighting the versatility of the technique. The findings suggest that laser sintering of copper particle-free inks could become a standard practice in the production of flexible electronics, offering significant advantages in terms of cost, efficiency, and substrate compatibility.
As the demand for flexible and wearable electronics continues to grow, so too does the need for innovative manufacturing techniques. Mohan’s work at the Institute of Innovative Mobility, Technische Hochschule Ingolstadt, represents a significant step forward in this field. By harnessing the power of laser sintering, the team has not only advanced the science of printed electronics but also laid the groundwork for future developments that could transform the energy landscape.
