New article: A new technique changes the color of assembled nanoparticles read more at here http://www.spinonews.com/index.php/science/item/3353-a-new-technique-changes-the-color-of-assembled-nanoparticles

Researchers from Lawrence Livermore national laboratory have created a technique to change the color of assembled nanoparticles with an electrical stimulant.

Using core/shell nanoparticles researchers improve color contrast and expand color schemes by using a combination of pigmentary color and structural color.

Jinkyu Han, lead author of a study, said, we were motivated by various examples in living organisms, such as birds, insects and plants. The assemblies of core/shell nanoparticles not only imitate interesting colors observed in living organisms, but can be applied in electronic paper displays and colored-reflective photonic displays.

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Using an electrophoretic deposition (EPD) process, the non-iridescent brilliant colors can be manipulated by shell thickness, particle concentration and external electrical stimuli. This technique is fully reversible with instant color changes as well as noticeable differences between transmitted and reflected colors.

Han explained, the photographs of nanostructures in an EPD cell in the OFF and ON states of applied voltage under diffused illumination. Black carbon tape (LLNL logo) with a white paper was put on the backside of the cell to distinguish the reflected and transmitted color more clearly.

The particle arrangement in the system is referred as "amorphous photonic crystal," which creates the resulting color from light reflection that does not change with viewing angles.

 

Han said, the angle independence of the observed colors from the assemblies is quite a unique and interesting property of our system and is ideal for display applications.