A new materials breakthrough from Kobe University could reshape how designers apply colour. Researchers have developed an inkjet-printable structural colour that removes the need for traditional pigments and dyes. As a result, this innovation offers a non-toxic, non-fading and potentially more sustainable alternative for a wide range of applications.

From Pigments To Structural Colour

Conventional colour relies on chemical pigments that absorb and reflect light. However, these pigments often degrade over time, leading to fading and environmental concerns. In contrast, structural colour emerges from the interaction between light and microscopic structures. This effect appears in nature, for example in butterfly wings and peacock feathers.

The Kobe University team, led by Hiroshi Sugimoto, uses silicon nanospheres to create colour. Each sphere reflects specific wavelengths depending on its size, typically between 100 and 200 nanometres. Because silicon is abundant and non-toxic, this approach supports more sustainable material development.

Solving The Printing Challenge

Until recently, structural colour remained difficult to print. When the liquid carrier evaporates, the nanospheres tend to clump together. Consequently, this clustering disrupts the way they interact with light and weakens the colour effect.

To solve this issue, the researchers coated each nanoparticle with a thin silica shell. This layer acts as a transparent buffer and prevents aggregation. As a result, the particles remain evenly dispersed in a liquid suspension. The team can now use standard inkjet printing techniques to apply structural colour onto flat and three-dimensional surfaces.

Transparent Yet Vivid: A New Material Quality

This technology introduces an unusual combination of properties. On the one hand, it produces vivid, reflective colours. On the other hand, it allows light to pass through the material. Typically, designers must choose between opacity and transparency. However, this system delivers both at once.

Moreover, the appearance changes depending on lighting conditions. Reflected light produces one colour, while transmitted light creates another. This effect, known as Mie scattering, opens new design opportunities. For instance, architects and product designers can develop surfaces that shift visually throughout the day.

Applications In Displays And Security Design

The technology also enables functional applications. For example, designers can print images onto screens that remain invisible during operation. When the display turns off, the image becomes visible. Therefore, this approach could support low-energy or even zero-energy information displays.

In addition, the complex optical behaviour makes replication difficult. This feature makes the material suitable for anti-counterfeiting solutions in packaging and product design.

Towards Scalable And Sustainable Colour

Finally, the research marks an important step towards industrial adoption. The material works with existing printing and coating systems, which supports scalability. As a result, structural colour could soon enter mainstream manufacturing.

For designers across disciplines, this innovation offers more than aesthetic value. It introduces a durable and environmentally responsible way to apply colour—one that relies on structure rather than chemical pigments.

Source: Kobe University via EurekAlert!
Photos: H. Yamana et al., Advanced Materials (2026)