A 3D printer. / Photo by: mebner1 via Pixabay


The application of 3D printing has allowed manufacturers and researchers to produce various products such as medical devices and food. However, one of its major disadvantages is the lack of colors on products other than gray and black. Thus, scientists looked into it and found a way to bring colors into 3D printing.

The scientists from The Institute of Photonic Sciences and Catalan Institution for Research and Advanced Studies designed and applied gold nanorods to produce the colors. The nanorods are efficient in absorbing the near-infrared part of the light spectrum. The rods have been coated with silica and mixed into powders of polyamide to print 3D objects. When they tested the gold nanorods, they observed that it converted light from a laser source with significant efficiency.

Before they addressed the color issue, the scientists initially investigated how to make the 3D printing process more energy efficient. In the study, the printer they used belonged to a class of printers called Selective Laser Sintering printers.

These devices need a laser to heat certain regions of a powdered material like polyamide or nylon. The laser heats and melts the material to compose a solid mass, a process called sintering. After that, the printers will add and selectively sinter new powdered material layer by layer to fabricate the desired 3D structure. Unfortunately, the process demands a lot of power.

To solve the energy problem, the scientists installed photosensitizers to the powders. The photosensitizers they used were made from specific materials, such as carbon nanotubes, carbon black, and graphene which can absorb light better than polymers.

But in the end, they selected the gold nanotubes as the photosensitizers over the carbon-based ones. This is because the gold photosensitizers performed better in light absorption than carbon black. Moreover, the gold model produces more brightly colored 3D structures, as reported at