Fuji Minoru and Sugimoto Hiroshi, two materials scientists at Kobe University, discovered what they call “nanospheres”; These are nearly invisible silicon crystals that reflect light in a way that can cover a full spectrum of bright, stable colors. These particles are able to reflect light due to extremely efficient scattering. The most interesting thing is that paint based on them requires only 10 percent of the amount needed in the case of using ordinary paint, which means a reduction in the final weight of the finished and painted product.

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A single layer of sparsely dispersed silicon nanoparticles, just 100 to 200 nanometers thick, displays vibrant colors but weighs less than half a gram per square meter, the researchers explain. They do not require as high a density as traditional pigments.

Such savings can have a huge impact on factors such as the cost of a painted aircraft and the amount of carbon dioxide emissions, as a lighter aircraft uses less fuel. Also, larger fuel volume means higher cost for a flight, which affects the cost of tickets for passengers.

For example, we can apply it to the coating of aircraft. Pigments and coatings on aircraft weigh several hundred kilograms. If we use our nanosphere-based dye, we can reduce the weight to less than 10%,
– explains Sugimoto Hiroshi.

Minoru and Hiroshi’s exploration focuses on structural color rather than pigmented color to showcase and sustain hues. First, it absorbs while reflecting wavelengths perceived by the human eye. Structural colors are intense and bright. They result from the interaction of light with periodic micro- and nanostructures that create color through interference, coherent scattering, or diffraction.

The additional “magic” of this invention is the constancy of color. While traditional structural colors change depending on viewing angle, these silicon nanospheres maintain the same color at all angles. They also do not fade over time.