Three-dimensional printing is very interesting technology that has some problems when printing in the free air. Researchers at Harvard University were able to construct a new 3D printing pen that overcomes this issue and it is able to create 3D structures without any additional support. A silver nanoparticle ink is used and immediately as it leaves the nozzle, it is annealed by an infrared laser.
This laser has to be quite close to the nozzle but not too much. If it is too close, it would heat the ink inside the nozzle and it would by solidified there. The infrared laser is, therefore, in the distance of 100 micrometres. The ink is heated there and creates the solid conductive wire. The wire can be thinner than a human hair and it is easy to created curved shapes. The new technique can be used for creating metallic interconnects, antennas, sensors, and other structures for electronic devices. In the future, the authors wants to try different materials like semiconductors or ceramics.