NEFU turns wood powder into a 3D-printable afterglow material

Wood powder has been converted into a 3D-printable feedstock that keeps glowing even after ultraviolet light is switched off.

This outcome turns a plentiful, renewable resource into a practical functional material that can give off light without any power supply, broadening the ways wood can be used in engineered systems.

Wood produces afterglow

In the printed test pieces, the afterglow could still be seen for 1.2 seconds once the ultraviolet lamp had gone dark.

At Northeast Forestry University (NEFU), associate professor Yingxiang Zhai and co-workers linked this lingering light to wood powder that had been chemically reworked.

Rather than relying on petroleum-derived binders, the team grafted oxygen-rich chemical groups onto the wood and made it printable using water.

That adjustment brought brightness and printability into step, despite those two traits usually pulling in opposite directions in wood-based inks.

How glow is sustained

The added groups shifted wood’s internal structure away from tidy crystalline order, creating more opportunity for molecules to lock together.

With more hydrogen bonds-weak attractions that help neighbouring molecules remain in place-the material reduced the motion that would normally bleed off stored energy.

Both of wood’s main constituents played a role, with each contributing part of the emission. Because less energy escaped as molecular movement, the material continued to release visible light after the lamp was turned off.

What the numbers showed

As the degree of chemical modification rose, performance increased markedly, with the afterglow lifetime extending from 35.4 to 358.7 ms.

Across the same range, the quantum yield-the fraction of absorbed energy emitted as light-went up from 0.93% to 4.60%.

The paper also referenced earlier formulations lasting 28.97 ms and 72.74 ms, which left this wood-based system well ahead. Those timescales fit short-duration markers and sensors, rather than items intended to glow throughout the night.

Printing process explained

Printing was possible because the modified wood could be made into a water-based paste that passed through a nozzle and then firmed up again.

This approach is known in engineering as direct ink writing, a 3D-printing method that extrudes paste through a nozzle and depends on tightly managed flow behaviour.

When only a small force was applied, the paste flowed steadily; after deposition, it regained enough stiffness to retain the target geometry.

That combination allowed the researchers to print detailed shapes without resorting to the plastic-heavy binders that many wood inks still require.

How shapes stayed

Once dried, the printed parts retained about 90% of their original form, although they shrank somewhat as water evaporated.

A porous internal structure-a web of tiny open spaces-formed as particles joined together, without needing extra hardening stages.

The material also demonstrated good mechanical behaviour and resistance to burning, which is important if glowing components are intended for handling.

Real-world use will still hinge on the application, because objects without permanent links can dissolve in water during storage or use.

How colour changed

The emitted colour was not constant, as different shorter and longer ultraviolet wavelengths activated different portions of the modified wood.

In one experiment, the researchers introduced a widely used dye and achieved a red afterglow with a 78.08 ms lifetime.

Humidity also influenced results, but rather than degrading permanently, the material recovered over repeated drying and humidity cycles.

This sensitivity suggests sensing applications, where changes in glow could indicate shifts in the surrounding environment.

Recycling adds value

Water was not only a risk to shape stability; it also enabled re-use, because printed parts could be returned to an ink state.

After reprocessing, the material was re-printed several times while maintaining stable light-emitting behaviour.

Environmental modelling added support: the ink’s global warming potential, a standard measure of warming impact, was 12.03 kg carbon dioxide equivalent.

That value was 27.6% of a simulated wood ink and 56.4% of another plant-fibre ink.

Wood gains new function

Previous work had already shown that untreated wood could produce a faint afterglow following a simpler chemical treatment.

Other studies had printed water-based wood structures, but generating light was not their primary focus.

In the context of NEFU’s wider research, the new material mattered because it brought these strands together, using a single biomass feedstock to create both printable ink and light emission.

By combining them, the work reduced the gap between laboratory demonstrations and objects designed for specific tasks.

Uses for glowing wood

NEFU’s findings initially point towards tailored interior components, anti-counterfeiting marks, and humidity-responsive sensing tools.

Because the glow appears after the excitation source stops, a printed identifier can stand out against typical fluorescent backgrounds.

Large-scale structural applications look more distant, given the short afterglow and the fact that water stability still depends on the final design.

Even with these constraints, a wood-based feedstock that can be printed, glow, and be recycled cleanly brings together an uncommon set of functions.

What comes next

Next steps include extending the glow duration, improving water resistance where required, and assessing how these prints withstand outdoor ageing.

If those challenges are met, a familiar material could take on subtle roles that ordinary wood has not been able to perform before.