Scientists develop ultrafast nanomotors powered by near-infrared light

Belgrade, Serbia – A team of researchers has developed a new class of ultrafast nanomotors powered by near-infrared (NIR) light, opening new possibilities for precise nanoscale transport in water — without the need for chemical fuels. The findings, published in a collaborative study led by scientists from the Vinča Institute of Nuclear Sciences, Technical University of Denmark, and Synchrotron SOLEIL, demonstrate how hybridizing titanium dioxide (TiO₂) with Janus silver-silver sulfide (Ag–Ag₂S) nanoparticles results in fuel-free nanomotors capable of reaching velocities up to 100 body lengths per second.

The team published their findings in Nano Research on April 24, 2025.

Unlike most nanoscale propulsion systems that rely on catalytic reactions or complex light-matter interactions, the newly developed nanomotors operate through a simple yet effective photothermal mechanism. Upon exposure to 700 nm NIR light, the Ag–Ag₂S component efficiently absorbs energy and creates a localized temperature gradient that propels the nanomotor via thermophoresis.

“What makes this system stand out is its combination of speed, directionality, and simplicity,” said Dr. Vladimir Djoković, senior author of the study. “We’re using sunlight-mimicking wavelengths to move hybrid nanoparticles in water with no added fuel or chemical reagents — just light.”

The team used optical microscopy and motion tracking to study over 400 nanomotors. The majority moved at speeds between 6 and 12 micrometers per second, while some reached nearly 23 µm/s. This places the new system among the fastest NIR-driven nanomotors reported to date.

To probe the underlying mechanism, the researchers employed vacuum ultraviolet velocity map imaging photoelectron spectroscopy (VUV-VMI PES) at Synchrotron SOLEIL. Their data revealed that the motion is not photocatalytic — despite TiO₂ and Ag–Ag₂S being active photocatalysts — but rather arises from photothermal effects within the Ag–Ag₂S domain. These effects result in directional motion due to a thermal pressure gradient along the hybrid nanoparticle.

Beyond advancing our understanding of light-driven nanoscale motion, this discovery offers potential applications in targeted delivery, environmental sensing, and microfluidic control. Because the system operates without fuel, it also holds promise for biocompatible and sustainable nanotechnologies.

“This work lays a foundation for future nanomachines designed to perform tasks like cleaning contaminated water or delivering therapeutics — all guided by light,” added Dr. Tijana Marić, main co-author from the Technical University of Denmark.

The international collaboration brings together expertise in nanomaterials, spectroscopy, and biomedical engineering and highlights the power of hybrid nanostructure design in emerging light-responsive technologies.

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 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 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.