Princeton University masterpiece: the first full 3D printing LED lights come out

3D printing is still limited to certain plastics, passive conductors, and several biomaterials. But the research team at the Princeton University has been able to print out 3D based on quantum dots LED (QD-LED), showing that different types of materials can be printed 3D, and fully integrated into the components with active device performance.

McAlpine and his colleagues from the Princeton University have mixed 5 different kinds of materials to print out the first 3D printing LED lights.

"Using 3D printing to achieve seamless integration of different materials is a huge challenge. Princeton University professor Michael McAlpine pointed out.

In their "Nano Letters" published in the report, the researchers describe five different materials seamlessly intertwined, including: 1) light emitting semiconductor nanoparticles; 2) an elastomeric matrix; 3) as organic polymer charge transport layer; 4) solid and liquid metal wire 5); UV transparent substrate adhesive layer.

The research team's approach consists of three key steps. First, determine the electrode, semiconductor and polymer has the desired function and to print the form; then, be careful to ensure that these materials can be dissolved in orthogonal solvents, in order to avoid the layer printing process damage to the integrity of the layer below; finally, interleaving pattern of these materials is designed by CAD constructs directly to realize the distribution.

Technology media ExtremeTech reported that the research team used a 3D printer developed by themselves, "ready-made 3D printers are not competent for this job. The research team's Ryan Whitwam said. "It took us more than half a year and $20 thousand to make the needed 3D printer. "

The bottom layer of each quantum dot LED is made up of silver nanoparticles, which connect the LED to the electronic circuit. At the top are two polymer layers that push the current upward into the next layer. This is where the real "quantum dots" lie, they are nanoscale semiconductor crystals, cadmium selenide nanoparticles encapsulated in zinc sulfide shells. Whenever an electron hits these nanoparticles, they emit orange or green light. The color of light can be controlled by changing the size of the nanoparticles. The top is a relatively common GaInP material, used to guide the electron away from the light emitting diode.

3D print embedded QLED x x x x 2 x 2 x 2.

As a proof of concept, the research team of 3D printing one based on LED quantum dots (QD-LED, CdSe nanoparticles based on ZnS shell, the top of the QD-LED, indium gallium) exhibit luminescence properties of pure and adjustable color.

By further integrating the 3D scanning of the surface topology, the team can also print the QD-LED onto a device with a curved surface, such as a contact lens.

The CAD model shows that the QD-LED element is conformal to the curvilinear substrate.

The third example of the research team is a package of LED x 2 x 2 x 2 cube, it is understood that each component of the cube and electronic devices are 3D printing. This proves that this difficult to use standard micro processing technology to complete the new architecture can be built through 3D printing.

Overall, the research team said, the results show that the potential application of 3D printing is much broader than we already know, and can integrate many different types of materials.

Working in 3D print QD-LED low resolution images

"We expect that this general strategy can be extended to other types of 3D printing active devices, such as MEMS devices, transistors, solar cells and photodiodes, etc.. Professor McAlpine says. "Overall, our results show a number of exciting applications, including the use of geometric tailoring of LED and multi-sensor devices, providing a new tool for the study of neuronal circuits. "

At the same time, 3D printing of active electronic components and biological structures may lead to the emergence of new bionic devices, such as prosthesis implants by stimulating nerve cells.

According to the research team, their future work will focus on solving some key challenges, including: 1) increased 3D printer resolution, the smaller 3D printing equipment; 2) improved performance and printing speed of printing equipment; 3) the integration of other categories of nano function modules and devices, including semiconductor, plasmon (plasmonic) and ferroelectric material (ferroelectric) etc..

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