Green Manufacturing of Highly Conductive Cu₂O and Cu Nanoparticles for Photonic-Sintered Printed Electronics

Recent advancements in smart electronics have brought an unprecedented number of electronic devices into our daily life, which leaves the burden of a growing e-waste. In particular, the emerging industry in printing science and technology has widely used Cu nanoparticles (NPs). To significantly reduce the e-waste on such metal NPs, it needs a solution in green manufacturing. Here, we introduce a simple green processing and material synthesis method. A nontoxic l-ascorbic acid, known as vitamin C in an aqueous solution, provides the driving force of both reducing and capping agents for a sustainable manufacturing of Cu-based NPs. Cu complex ions mixed with a reducing agent, l-ascorbic acid, prevents aggregation of NPs. An intermediate product, Cu2O NPs that can only absorb photonic energy are used to fabricate an electronic system due to a superior electrical resistivity (4.2 × 10–6 Ω·cm). The comprehensive study using spectroscopy, high-resolution electron microscopy, and X-ray diffraction fully characterizes the synthesized NPs. A demonstration of an electronic circuit that is prepared by a screen-printing and photonic sintering shows the potential for an eco-friendly manufacturing of various types of printed electronics.