Deoxyribonucleic acid is the basis of life, but soon the physical structure could provide the basis for new optical devices. This is according to a research team based at Northwestern University, who think the thread-like chain of nucleotides carrying the genetic instructions could provide the design basis for developing photonic crystals.
A photonic crystal is an optical nanostructure that influences the motion of photons. In theory, the crystals can find uses wherever light must be manipulated. Current applications include thin-film optics with coatings for lenses. The crystals are also similar to the types used in computer, television and smartphone displays.
The researchers have shown that by using synthetic DNA to assemble particles into crystalline lattices, this can pave the way for considerably lighter and thinner optical displays. Here the lead researcher, Professor George Schatz draws a comparison: “One component of the display is the back-reflector, a mirror-like device that directs the light emitted by the LCD to the viewer. These reflectors are made using layered polymers that are much thicker and heavier than our crystals.”
The new technology substitutes such polymers with gold nanocrystals. Moreover, it creates space between them, which leaves pockets of air. The net effect of this is to create a lighter and more compact structure. This output is reconfigurable whist maintaining highly reflective properties.
The process is based on earlier research which showed how synthetic DNA can be connected to gold nanoparticles to produce new materials that are not found in nature. More recent research has shown how crystals can be made from particles connected to DNA. The researchers have now perfected this to fabricate three-dimensional crystalline structures.
The research also showed that by altering the DNA strand sequence leads to changes to the hape of the crystalline structure. This allows the scientists to alter the arrangement of the particles in space. These new arrangements have special optical properties.
The findings have been published in the journal Proceedings of the National Academy of Sciences. The paper is titled “Design principles for photonic crystals based on plasmonic nanoparticle superlattices.”
