In the ongoing pursuit of materials with extreme performance, scientists have made another major breakthrough. A research team from Aalto University in Finland has successfully developed an innovative material called “Super Black Wood.” Through nano-scale structural modifications, they achieved an astonishing 99.65% light absorption rate—virtually “devouring” all incident light. This achievement not only opens new avenues for high-value applications of wood but also introduces a new material option for fields like optics and energy.

From Ordinary Wood to Super Black Material: A Dramatic Transformation

At the heart of this breakthrough lies the nano-level reengineering of the wood’s cell wall structure. The researchers discovered that by precisely controlling the lignin content and increasing the carbonization temperature, they could reduce the size of wood cell walls from the micrometer to the nanometer scale. This structural transformation dramatically suppresses light scattering, significantly lowering the material’s reflectivity.

“While standard carbonized wood is black, it falls far short of being ‘super black.’ The key was overcoming the limitations of carbonization temperature and lignin content, which allowed us to reduce reflectivity by an entire order of magnitude,” the researchers noted.

The development process involved numerous setbacks. For over six months, the light absorption rate hovered around 99%. The breakthrough came when they raised the carbonization temperature to 1500°C. Under an electron microscope, the wood cell walls revealed a new nanostructure, and the light absorption rate soared to 99.65%—officially reaching super black status.

Advantages and Future Applications：

Compared to traditional super black materials, this wood-based innovation offers several unique advantages:

Environmentally sustainable: Made entirely from renewable wood with a greener production process

Structurally robust: Solves the fragility issue common in most super black materials

Cost-effective: Does not require ultra-clean lab environments or complex fabrication

Performance testing showed the material’s impressive capabilities. In collaboration with Professor Zhipei Sun’s team at Aalto University, the material demonstrated superior efficiency when used as a laser light collector. Its near-perfect light absorption greatly reduces stray light interference in optical devices, making it suitable for:

Astronomical telescopes: Minimizing solar background interference

Optical lenses: Enhancing imaging quality

Laser systems: Absorbing laser reflections to protect human eyes

Solar collectors: Boosting photothermal conversion efficiency

Nature-Inspired Innovation：

The super black phenomenon is not uncommon in nature. Creatures like deep-sea fish and birds-of-paradise have evolved ultra-black features for camouflage or mating displays. The research team drew inspiration from such natural structures—especially the way light is absorbed in forest environments.

Picture a forest stretching several kilometers high. As light passes through these towering ‘walls of trees,’ it’s reflected so many times that it’s almost entirely absorbed. We replicated this highly efficient light-trapping mechanism, the team explained.

Previously developed super black materials, such as vertically aligned carbon nanotube arrays (99.96% absorption) and etched nickel-phosphorus alloys, often suffer from fragile structures or demanding fabrication conditions. In contrast, this wood-based material offers better environmental adaptability and mechanical strength.

A Cross-Disciplinary Research Journey：

The project integrated insights from multiple scientific disciplines. The team built on their experience with transparent wood—where refractive-index-matched polymers fill the wood’s pores to allow light transmission. Interestingly, the same multi-level porous structure, when carbonized, becomes ideal for light absorption instead.

Finite element modeling played a critical role. When researchers couldn’t initially explain the sharp increase in blackness, computer simulations of the wood’s structure during different treatment stages revealed how nano-scale architecture directly affects light behavior.