Controlling nucleation and growth enables size-tunable nickel nanoparticles with tailored electrical and magnetic properties

Miniaturization and integration of modern electronic devices require conductive materials with precisely controlled dimensions and reliable performance. Nickel nanoparticles have long been considered essential functional materials for applications such as multilayer ceramic capacitors, printed electronics, electromagnetic shielding, and magnetic devices because of their excellent electrical conductivity, ferromagnetism, mechanical ductility, and corrosion resistance. However, achieving scalable synthesis of nickel nanoparticles with narrow size distributions while maintaining their intrinsic properties remains a significant challenge, particularly when both performance and manufacturing feasibility must be considered simultaneously.

A research team from Beijing University of Chemical Technology, in collaboration with GRINM NEXUSX Advanced Materials Co., Ltd., has developed a controllable aqueous-phase synthesis strategy for uniform spherical nickel nanoparticles. By regulating both the dosage and the timing of addition of triethanolamine (TEA), a coordinating agent, the researchers successfully decoupled nucleation and growth processes during particle formation. This approach enabled precise tuning of particle sizes across a wide range from 95 to 270 nanometers, offering improved control compared with conventional synthesis strategies.

The study was recently published in Nano Research on April 10.

Traditional liquid-phase synthesis methods for metal nanoparticles often rely on strong organic ligands or harsh reaction environments to regulate particle size and morphology. Although these approaches can achieve morphological control, they frequently introduce surface passivation that compromises electrical and magnetic performance. In contrast, the newly developed method uses a mild aqueous reduction system, which provides improved environmental compatibility and scalability while preserving the intrinsic metallic properties of nickel nanoparticles. The approach also reduces process complexity, making it more attractive for industrial production.

The researchers demonstrated that the timing of TEA introduction plays a critical role in determining particle size. Early addition will lead to fewer nuclei and larger final Ni particles. In contrast, delaying TEA addition will suppress growth, resulting in significantly smaller and more uniform nanoparticles. This decoupling strategy provides new mechanistic insight into particle formation in aqueous reduction systems and highlights the importance of independently controlling nucleation and growth stages.

Beyond synthesis, the relationship between particle size and functional performance was systematically investigated. Electrical conductivity measurements were conducted using both hot-pressed pellets and printed ink lines fabricated from the synthesized nanoparticles. Results showed that conductivity increased with particle size, which can be attributed to enhanced interparticle neck formation and reduced grain boundary scattering during sintering. The magnitude remianed even when pellets were reduced to micrometer-thick, demonstrating preservation of intrinsic electrical properties.

Magnetic characterization revealed a size-dependent behavior. Saturation magnetization and remanent magnetization increased with particle size, while coercivity decreased, consistent with a transition from surface-disordered magnetic structures to bulk-like multidomain magnetic behavior in larger particles. These findings provide valuable guidance for tailoring magnetic properties of nickel nanoparticles for specific technological applications.

To demonstrate practical applicability, the researchers formulated nickel-based conductive ink by dispersing the nanoparticles in a glycerol-based medium. The ink was successfully used to draw conductive circuits on standard paper substrates, which were able to power a light-emitting diode under 3V. This proof-of-concept experiment highlights the potential of the materials for flexible electronics, printed circuits, and low-cost electronic manufacturing.

The strategy provides a scalable pathway for producing functional metal nanoparticles with tunable properties and could potentially be extended to other metal systems where precise control of nucleation and growth is critical. The findings are expected to advance the development of conductive materials for electronic components, wearable electronics, electromagnetic devices, and magnetic technologies.

DOI Link:

https://doi.org/10.26599/NR.2026.94908493

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.