The future of stretchable electronics is beyond imagination. In the future, through magic ink, we can use ball pens to "draw" LEDs on any surface such as paper, textiles, rubber, plastics and 3D objects.
The team at Washington University in St. Louis has developed a stretchable LED ink for inkjet. Now scientists have made new progress. Chuan Wang’s laboratory pointed out that handwritten stationery is obviously the next step after printers. The team improved the developed ink and modified it to give Commonly used ballpoint pens, an inexpensive and accessible device for everyone, allowing anyone interested in writing multicolor LEDs and building photodetectors.
The LED combination is a bit like a sandwich, consisting of an anode layer, an emission layer, and a cathode layer. As long as the ink is applied to the other layer and the colors are not mixed, it can become an LED, and then connected to the power supply. This flexible and stretchable ink Combination can emit a variety of color light.
Image credit: Washington University in St. Louis, USA
The team used the convenience of a ball pen to fill inks made of conductive polymers, metal nanowires and perovskite crystal materials, allowing people to easily and quickly create various functional devices, such as smart packaging and other disposable electronics, just like using colored pens. products and personal wearable devices such as biomedical sensors.
In order for the ink to be used in standard ballpoint pens, the team also adjusted the ink wettability and improved writing properties, and also ensured that the ink could write on porous and fibrous substrates such as paper and textiles, which would otherwise flow or mix together . Graduate student Junyi Zhao said that the ink developed by the team is a special configuration, but the pen is universal, so each layer of the ink must be able to withstand deformation, and it will not affect performance after bending, stretching and twisting.
The team expects that the device will have a wide range of applications in the future, probably only limited by the user's imagination. Direct uses include education, popular science, electronic packaging, clothing, and medical sensors and bandages. Wang said the team is also optimistic about the application of ink in the medical field. Handwritten light emitters and detectors can be used in wearable biomedical sensors and bandages. Devices draw photodetectors and infrared LEDs to measure heartbeat, blood oxygen saturation or Accelerates wound healing.
