Just Press Print And Your LED Light Will Be Delivered To Your Desk!

Princeton University researchers have developed a 3D printer which prints LEDs in layers. The research was headed by Yong Lin Kong and Ian Tamargo, of the Michael McAlpine Research Group and was sponsored by Air Force of Scientific Research and the Defense Advanced Research Project Agency.

With 3D printing technology, McAlpine could  print “emissive semiconducting inorganic nanoparticles, elastomeric matrix, organic polymers as charge transport layers, solid and liquid metal leads and a UV-adhesive transparent substrate layer cube of encapsulated LEDs,” according to a press release. “What we have presented here is an additional method to integrate electronics that can take into consideration the three-dimensional geometry of an object,” Kong said in the press release. He added that earlier, only simple mechanical structures were printed with the help of 3D technology, but now McAlpine has developed the first 3D printer to print LED lights.

The Princeton University’s team first made a breakthrough a year ago when it printed 3D bionic ears—devices that can catch sound frequencies beyond the capacity of human ear, out of bovine cells.

With the help of a custom 3D printer, the team developed quantum dot LEDs with five different materials. The researchers printed the LED in five layers. The bottom layer of is made of silver nanoparticles, which connect the LED to the electronic circuit. On top of this layer are two polymer layers that push electrical current toward the next layer. This layer consists of the real quantum dots.  These are nanoscale semiconductor crystals, and in this case it is cadmium selenide nanoparticles inside a zinc sulfide shell. Whenever an electron hits these nanoparticles, they give out an orange or green light. This colour can be controlled by changing the size of the nanoparticles. Finally, the top layer is made of ordinary gallium indium that pushes the electrons away from the LED.

How it works

3D LED printer works in the same way as other 3D printers. First it puts down a single layer of LED, then adds the next layer made of a different material. When all five layers are laid, it becomes a functional quantum dot LED.

3D printer that prints LEDs in layers with different materials

Besides printing the quantum dot LEDs on a flat surface, the researchers also developed a convex surface like a contact lens, and also created a 3D cube of quantum dot LEDs with electronics and components built in.

The printer that took two years to develop and cost $20,000.

24 Jun