Gold nanoparticles unlock vibrant structural colors across the visible spectrum

June 7, 2026 report Gold nanoparticles unlock vibrant structural colors across the visible spectrum Sam Jarman Author Gaby Clark Scientific Editor Robert Egan Associate Editor Colloidal photonic glasses offer an appealing way to produce vivid colors without any chemical dyes—but so far, a stubborn optical effect has long prevented them from generating a true red color. Now, Yuwon Jeon and colleagues at KU-KIST in Seoul have developed a new approach that overcomes this limitation, producing bright, stable colors spanning the full visible spectrum. The research has been published in Proceedings of the National Academy of Sciences. Bleeding blue Most synthetic colors are made from pigments: chemicals that absorb certain wavelengths of light while reflecting others. In contrast, "structural color" is created by the physical arrangement of tiny nanostructures within a material that determine which wavelengths of light are reflected. Colloidal photonic glasses exploit this principle by suspending nanoparticles in a loosely organized arrangement. When light hits the material, the spacing between particles causes certain wavelengths to scatter more strongly than others, producing color without any dye. Unlike chemical pigments, these structures can't be bleached by sunlight and will not leach into water. The problem is that particles of this size also scatter shorter, bluer wavelengths more strongly—an effect similar to why the sky appears blue. This blue background light bleeds into the reflected light, making it especially difficult to achieve vibrant colors with longer, redder wavelengths. Carefully engineered nanoparticles To tackle this problem, Jeon's team engineered colloidal nanoparticles with a tiny gold core just 20 nanometers across, surrounded by a silica shell. They chose gold for a particularly useful optical property it exhibits: it absorbs light at shorter wavelengths, effectively filtering out the blue background before it can contaminate the reflected color. The team suspended these gold-core, silica-shell particles in a transparent resin carefully chosen to have nearly the same refractive index as the particles themselves, further reducing unwanted scattering within the material. Together, the two effects suppress the blue leakage that had plagued earlier photonic glasses. In turn, the structure's natural color (as determined by the spacing between the nanoparticles) could come through cleanly. Colors across the spectrum The material can be painted directly onto surfaces and hardened under ultraviolet light to form a thin, durable film. With 230 nanometer particles, it reflects only red wavelengths, producing a saturated red even in direct sunlight. Shrinking the particles to around 180 nanometers shifts the color to green, while reducing them further to 160 nm yields a deep blue. Crucially, its color does not change with viewing angle: a key advantage over other structural color approaches. Because it arises from within the material's structure rather than a surface coating, Jeon's team also expect it to be highly durable. Path to scalability The team's results establish clearer design rules for engineering structural colors in photonic glasses, and suggest a promising path towards structural color paints that are genuinely competitive with conventional pigments. Since gold accounts for only a tiny fraction of the material by weight, they are confident that its cost won't be a barrier—though they are already exploring cheaper alternatives. If their approach can be replicated on an industrial scale, Jeon and colleagues ultimately hope it could be applied in areas ranging from long-lasting architectural coatings to anti-counterfeiting materials. Written for you by our author Sam Jarman, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. Publication details Yuwon Jeon et al, Metallodielectric photonic glass paints enable hyperchromatic, angle-independent structural color across the full visible spectrum, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2608405123 Journal information: Proceedings of the National Academy of Sciences © 2026 Science X Network