The interaction of silver materials with light is well-known as the basis of film photography. But, there are much more sophisticated interactions when we consider very, very small particles of silver that could have applications in a wide range of technologies.
Research in the International Journal of Nanoparticles has looked at the behaviour of the tiniest of silver particles, just billionths of a metre in diameter when exposed to light. The behaviour of these silver nanoparticles when exposed to light is different depending on the exact size of the particles.
The team has modelled the absorption, scattering, and quenching of light of different wavelengths with silver nanoparticles from 10 to 240 nanometres in diameter. They found that the smaller nanoparticles primarily absorb light. This could be useful in boosting photothermal effects used in targeted medical therapies for cancer.
By contrast, larger particles, rather than absorbing light, scatter it. This phenomenon might be used to make reflective coatings and solar energy capture devices.
Those particles that are of intermediate size, 40 to 60 nanometres, displayed a third type of behaviour, plasmonic resonance. In this phenomenon, the incident light causes the conducting electrons in the silver to oscillate. This action could be used to detect chemicals in medical or environmental samples, as the presence of chemicals of interest even in very low concentration will change the pattern of these oscillations.
This new understanding of the behaviour of silver nanoparticles could thus open up a range of applications in medicine, biomedical, chemical, and environmental research. The team adds that not all silver nanoparticles are created equal, and this could also be useful in different technologies. For example, silver nanoparticles with complex geometries such as internal layers, like an onion or hollow nanoparticles might behave differently again. Their model could open up the exploration of such complex silver nanoparticles, which might be even more amenable to fine-tuning for specific applications.
Lamsiah, A., Atmani, E.H., Meziane, J., Fazouan, N. and Oumouloud, M. (2026) ‘Influence of particle size on optical scattering properties of silver nanoparticles’, Int. J. Nanoparticles, Vol. 15, No. 5, pp.1–17.
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