Chemists at the University of California, Riverside, are developing a future display technology using nanoscale-sized iron oxide rods that shine when exposed to an external magnetic field.
Though in its early stages, the research could pave the way for producing magnetically responsive, ultra high-res displays with significantly reduced dimensions and power demands.
The researchers have shown in the past that by using a simple magnet, the color of iron oxide particles suspended in water can be manipulated in response to the strength and orientation of a magnetic field.
The latest development is the application of silica to the iron oxide particles to form chains of light emitting particles that refract the visible light into brilliant colors when magnetically charged.
To do this, a thin layer of silica is applied to iron oxide molecules in a water solution. Then, a magnetic field is applied to assemble the particles into chains. Next, in order to stabilize the chain structure, the chains are coated with additional silica to form a shell, making tiny rods or nanorods. When an external magnetic field is applied, the nanorods align themselves parallel to one another like a set of tiny flashlights.
It is the arrangement of nanorods that effectively diffracts light and displays a color, while it is the spacing between the particles that determines the actual color that is shown.
Currently, the process can show a single color as the particle spacing is fixed after the silica coating is applied to the chains. In order to show different colors the researchers explain that the nanorods could be used in clusters of different sizes, effectively varying the interparticle spacing. The researchers are now working on achieving two colors, one at a time. If successful, this would allow a screen or pixel to display one color for a while, and a different one later.
- Micro-onions and magnetic ink (nanowerk.com)