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Ultrathin materials such as graphene promise a revolution in nanoscience and technology. Researchers at Chalmers University of Technology, Sweden, have...

Energy-Efficient Tuning of Spintronic Neurons to Imitate the Non-linear Oscillatory Neural Networks of the Human Brain

The human brain efficiently executes highly sophisticated tasks, such as image and speech recognition, with an exceptionally lower energy budget...

It's widely known that submerging a pared apple in saltwater prevents oxidation and browning, but did you know that saltwater can also protect fragile quantum dot (QD) materials? A research team led by Prof. Chen Hsueh-Shih of the Department of Materials Science & Engineering at National Tsing Hua University in Taiwan has recently developed the world's first inkjet technique for using saltwater to encapsulate QD materials, which not only resists water and oxygen corrosion, but can also be uniformly printed as a flexible plastic film on a micro LED array for use in high-resolution bendable screens for mobile phones, glasses, etc. In order to create ultra-slim and bendable displays with higher resolution, higher brightness, and a longer lifetime for use in the goggles used in augmented reality (AR) and virtual reality (VR), and for watches and other wearable electronic devices, Apple, Samsung, and other major panel manufacturers have heavily invested in the development of micro LED to replace the OLED displays currently in use. Arranging millions of micro-LEDs less than 100 μm in size on a substrate presents some major difficulties. According to Chen, many manufacturers use a stamping method to move millions of red, green, and blue micro LEDs one-by-one to the substrate, but if just a few chips don't stick, the screen will be marred by defective pixels. One way of solving this problem is to use inkjet printing to print micro pixels instead of moving micro LEDs, which is more efficient and cost effective. However, when the QD solution is ejected from the inkjet printer, convection occurs inside the droplets, pushing the material to the periphery, leaving it unevenly distributed, with a lighter color in the center and a darker color on the periphery, similar in appearance to the so-called "coffee ring phenomenon" seen in a drop of coffee dropped onto a light surface. By adding saltwater (a sodium chloride solution) to the QD solution, Chen's research team successfully encapsulated the QDs, which formed into crystals, what Chen describes as "grabbing hold of the quantum dots and condensing them into uniformly distributed dots." These encapsulated QDs are also more stable and corrosion resistant, like apples soaked in saltwater. The team member who came up with the idea of soaking the quantum dots in saltwater was Dr. Ho Shih-Jung, also of the Department of Materials Science and Engineering at National Tsing Hua University. He observed from photomicrographs that QD material without added saltwater scatters into irregular shapes when ejected from an inkjet printer, but by adding saltwater, they gradually shrink and converge into uniform and beautiful crystals. According to Ho, adding saltwater to the QD solution also makes it possible to spray smaller droplets, explaining that the droplet size of current QD printers is about 30 μm to 50 μm, but by adding saltwater the size can be reduced to as small as 3.7 μm, which is about 1/20 the diameter of a human hair, hence the better resolution. This innovative research has been published in a recent issue of ACS Applied Materials & Interfaces, and the material they have developed is currently being patented in the United States and Taiwan.

World’s first inkjet technique for using saltwater to encapsulate QD materials Developed

It's widely known that submerging a pared apple in saltwater prevents oxidation and browning, but did you know that saltwater...

Researchers at Sandia National Laboratories have developed an array of processors coated with titanium oxide that has the potential to revolutionize technologies like voice recognition, image processing and autonomous driving. Photo Courtesy of Sandia National Laboratories.

Material found in house paint may spur technology revolution

Researchers at Sandia National Laboratories have developed an array of processors coated with titanium oxide that has the potential to...

Machinery of Photosynthesis Supercharges Solar Energy to Hydrogen Fuel Conversion

Global economic growth comes with increasing demand for energy, but stepping up energy production can be challenging. Recently, scientists have...

Artificial materials for more efficient electronics

Scanning transmission electron micrscopy image of superlattice consisting of an alternating sequence of 5 atomic unit cells of neodymium nickelate...

False-colored scanning electron microscope images of the device, general view (left), and zoom-in on the nano-ram (right). The platform is 1.5 µm wide and 3 µm long, with 80 × 500 nm support beams. The optical ring diameter is 20 µm, and the optical ring-to-platform gap is 100 nm. Close to 1.55 µm wavelength light is coupled in and out of the ring by optical waveguides through a 200 nm gap. Electrostatic actuation is performed with a side-gate 250 nm away from the nanoresonator. Courtesy: © Nature Communications

Mass-spectrometry breakthrough paves the way to detecting viruses

False-colored scanning electron microscope images of the device, general view (left), and zoom-in on the nano-ram (right). The platform is...

Resonant nanoantennas to slow and steer light

An artist rendering of a high-Q metasurface beamsplitter. These “high-quality-factor” or “high-Q” resonators could lead to novel ways of manipulating...

Two composite pictures, each using the TSOM method, show a single nanocontaminant on a semiconductor sample, recorded at several different distances from the lens of an optical microscope. Red indicates highest intensity of scattered light, blue the lowest. Courtesy: NIST.

New method detects nanoscale contaminants in Semiconductor devices

Two composite pictures, each using the TSOM method, show a single nanocontaminant on a semiconductor sample, recorded at several different...

Powerful, Quick-and-easy tool for mutation detection with nanopore technique