Above: The fully 3D printed flexible organic light-emitting diode (OLED) display prototype is about 1.5 inches on each side and has 64 pixels/Image Source: McAlpine Group, University of Minnesota
Researchers at the University of Minnesota Twin Cities used a customized printer to create a fully 3D printed OLED display in a ground-breaking new study. The discovery could lead to low-cost a flexible organic light-emitting diode (OLED) display that can be mass-produced at home using 3D printers rather than by technicians in expensive microfabrication facilities in the future.
Science Advances, a peer-reviewed scientific journal published by the American Association for the Advancement of Science, published the findings (AAAS).
The technology behind OLED displays is based on the conversion of electricity into light via an organic material layer. OLEDs are high-quality digital displays that can be made flexible and used in both large-scale devices like television screens and monitors and handheld electronics like smartphones. OLED displays have grown in popularity due to their light weight, low power consumption, thin and flexible design, and wide viewing angle and high contrast ratio.
“OLED displays are usually produced in big, expensive, ultra-clean fabrication facilities. We wanted to see if we could basically condense all of that down and print an OLED display on our table-top 3D printer, which was custom built and costs about the same as a Tesla Model S.”
3D Printed OLED Displays
Above: 3D printing of OLED displays in action/Video Source: University of Minnesota Twin Cities
The team had previously attempted to created 3D printed OLED displays, but they were frustrated by the uniformity of the light-emitting layers. Other groups used spin-coating or thermal evaporation to deposit certain components and create functional devices in addition to partially printing displays.
The University of Minnesota research team combined two different modes of printing in this new study to print the six device layers, resulting in a fully 3D printed OLED display. The electrodes, interconnects, insulation, and encapsulation were all extrusion printed, while the active layers were spray printed at room temperature on the same 3D printer. The display prototype had 64 pixels on each side and measured about 1.5 inches on each side. Every pixel was functional and displayed light.
“I thought I would get something, but maybe not a fully working display. But then it turns out all the pixels were working, and I can display the text I designed. My first reaction was ‘It is real!’ I was not able to sleep, the whole night.”
Su said the 3D-printed display was also flexible and could be packaged in an encapsulating material, which could make it useful for a wide variety of applications.
“The device exhibited a relatively stable emission over the 2,000 bending cycles, suggesting that fully 3D printed OLEDs can potentially be used for important applications in soft electronics and wearable devices,” Su said.
The next step, according to the researchers, is to 3D print OLED displays with higher resolution and improved brightness.
McAlpine added, “The nice part about our research is that the manufacturing is all built in, so we’re not talking 20 years out with some ‘pie in the sky’ vision. This is something that we actually manufactured in the lab, and it is not hard to imagine that you could translate this to printing all kinds of displays ourselves at home or on the go within just a few years, on a small portable printer.”
In addition to McAlpine and Su, the research team included Xia Ouyang, a postdoctoral researcher at the University of Minnesota, Sung Hyun Park, who is now a senior researcher at the Korea Institute of Industrial Technology, and Song Ih Ahn, an assistant professor of mechanical engineering at Pusan National University in Korea.
The research was primarily supported by the National Institutes of Health’s National Institute of Biomedical Imaging and Bioengineering (Award No. 1DP2EB020537), with additional funding provided by The Boeing Company and the Minnesota Discovery, Research, and InnoVation Economy (MnDRIVE) Initiative through the State of Minnesota. Parts of this research were carried out at the Minnesota Nano Center, which is funded by the National Science Foundation via the National Nano Coordinated Infrastructure Network (NNCI).
The research paper titled “3D printed flexible organic light-emitting diode displays,” has been published in Science Advances.
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