New Ultra-Black Car Paint Absorbs 99.9% of Visible Light

Inspired by the demand for luxury finishes, researchers created a coating that pushes blackness toward its limits.

Imagine a car so black it behaves like a sort of black hole on wheels. Instead of bouncing back sunlight toward your eyes, almost every ray is swallowed, giving the vehicle an unusually flat and mysterious appearance, even under bright daylight.

Materials scientists have been chasing this effect for years, but there has always been a problem that the blackest coatings were often too fragile, too expensive, or too difficult to apply to real-world products. 

Now, researchers in China report a practical process for making an ultra-black automotive coating that absorbs an average of 99.90 percent of visible light while meeting key durability requirements expected from automotive paints. 

“In this study, we present an easily processable strategy for the construction of ultra-black coatings with an extraordinary visible-light absorption value exceeding 99.90 percent and remarkable blackness values,” the study authors note.

This achievement could bring a technology once limited to laboratory demonstrations and concept vehicles much closer to mass-produced cars.

What makes ultra-black coating so hard to achieve

The challenge was never simply making something darker. Scientists have long known that carbon nanotubes can trap extraordinary amounts of light. 

This principle was famously demonstrated by the ultra-black coating Vantablack, and in 2019, a BMW concept vehicle coated with a carbon nanotube-based material created the illusion of a three-dimensional car turning into a flat silhouette. 

However, such coatings are difficult to manufacture, expensive, and often unsuitable for the harsh conditions that automotive paints must endure, including moisture, heat, and physical wear. 

The new study focuses on solving this practical problem rather than merely setting another darkness record.

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Moreover, conventional black automotive paints rely primarily on carbon black pigments. These pigments absorb a large fraction of incoming light, but there is a natural limit to how much darkness can be achieved through pigment absorption alone. 

This is because, beyond a certain point, additional pigment provides diminishing returns because some light is still reflected from the coating’s surface.

“The design of structural absorption based on high intrinsic light absorption nanomaterials is the key point to realize the upgradation from black coatings to ultra-black coatings,” the study authors note.

Mixing carbon black with carbon nanotubes

To overcome this limitation, the researchers combined two different carbon-based materials: traditional carbon black pigment and carbon nanotubes. 

Carbon nanotubes are tiny hollow cylinders made entirely of carbon atoms. They are excellent light absorbers, but they tend to clump together, making them difficult to distribute evenly in paints and coatings.

The team developed a stable, nanoscale composite in which carbon black particles and carbon nanotubes were blended together using a high-energy milling process. 

This process created a well-dispersed mixture that could remain stable in water-based formulations, an important requirement for industrial manufacturing. The resulting composite was then incorporated into a coating binder and applied using conventional spray-coating methods similar to those already used in the automotive industry.

However, simply adding nanotubes was not enough. The real breakthrough came from how the researchers arranged these materials at the microscopic scale.

Turning the coating into a light trap

What makes the coating special is not just the chemistry but also its structure. Instead of relying solely on the inherent light-absorbing ability of carbon particles, the coating creates what researchers call ‘structural absorption.’ 

The carbon nanotubes and carbon black particles form a microscopic landscape filled with tiny peaks, valleys, and interconnected features.

When light enters this structure, it becomes trapped and bounces repeatedly between these nanoscale features. With each bounce, more energy is absorbed until very little light escapes back to the observer. 

“The enhanced light absorption capability of CB-CNT ultra-black coating to the CB black coating mainly originates from the structural optical trap,” the study authors added.

This combination of intrinsic absorption and structural light trapping allowed the coating to absorb an average of 99.90 percent of visible light wavelengths. At that level of absorption, surface details become difficult for the human eye to perceive. 

Objects coated with such materials can appear strangely flat because the visual cues created by reflected light largely disappear.

Just as important, the coating survived tests designed to mimic real-world conditions. The researchers reported strong resistance to humidity and water exposure, maintaining its appearance and performance without significant degradation. 

This durability is one of the key differences separating the new coating from many earlier ultra-black materials that struggled outside controlled laboratory environments.

Why this matters beyond luxury cars

The study was motivated by the demand for premium automotive finishes. In China, especially, dark-toned car colors have become an important selling point in the luxury vehicle market.

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“Deep black finishes have long been the premium choice and signature color for luxury cars due to their elegant appearance, powerful visual impact, and luxurious undertone. As a result, automotive coating companies have been actively pursuing innovations in color technology to develop mass-processable ultra-black coating solutions with extreme blackness,” the study authors said.

However, the technology isn’t just limited to luxury ultra-black cars. It could find uses wherever unwanted reflections are a problem, including optical instruments, sensors, cameras, and astronomical equipment.

The coating is not ready for commercial vehicles, though. The team still needs to validate long-term performance and large-scale manufacturing. Moreover, researchers plan to explore higher nanotube concentrations and multilayer coating designs that could absorb even more light. 

The study is published in the journal Matter & Light.