Highly Aligned Plasmonic Gold Nanorods in a DNA matrix
A research team composed of researchers from the Graduate School of Nanoscience and Technology and the Department of Chemistry has recently reported about the fabrication of meta-color film using gold nanorods (GNRs) using inexpensive DNA (deoxyribonucleic acid). DNA was extracted inexpensively from fish (salmon). This advancement opens up a way to use natural abundant DNA in fabrication due its highly regular periodicity at the nanometer scale. Future applications can be widely exploited in optoelectronic devices and sensors.
DNA is one of the most abundant biomaterials in nature. It is found in all living organisms. It has unique characteristics; its double helix bearing precise dimensions and its exceptional overall negative charge on the surface enables for rich chemical properties. Thus, there have been many attempts to combine the use of DNA with other functional materials. In this research, the team at KAIST has developed a way to make plasmonic gold nanorod (GNR) film that can be applied in the display application using very well aligned DNA materials.
Plasmonic nanoparticles, such as GNRs, have unique optical and electrical properties. Importantly, surface plasmon resonance (SPR) exists as a kind of delocalized form of electron a little akin to Pi-aromatic it’s found in organic compounds. This has attracted attention in the design of key next-generation optoelectronic device platforms. Previously, only micrometer-level success was achieved, thus practical applications were limited due to alignment problems in a large area over centimeters. Some studies, to date, have shown that the orientation of the nanoparticles is only successful locally in the micrometer region.
The KAIST researchers developed a technology that can orient GNRs in large areas of a few centimeters, using DNA that is readily available in nature as a matrix. Using this technology, highly oriented thin films of GNRs are fabricated with various alignments such as parallel, vertical, and zigzag forms.
The resultant DNA-GNR films show the high optical anisotropy, which can also be used to make plasmonic color filters. In detail, the slowly sheared DNA films show the transmission optical microscopy images show green and red colors with polarizer(P)⊥ pulling direction and P || pulling direction, respectively (Figure below). In particular, this study used DNA extracted from salmon, which is 1000 times less costly than artificially synthesized DNA material. In addition, DNA chains can be easily controlled by applying a simple shearing force, making it possible to apply them to large-scale fabrication and optoelectronic devices.
“This research has developed a technique to align the mixture using DNA and gold nanoparticle interactions (Figure),” professor Dong Ki Yoon, the principal investigator said. “It can be extended to orient various kinds of nanoparticles that have interesting physical and chemical properties; it is expected to be widely used in various photoelectric devices and sensor applications,” he adds.
Dong Ki Yoon, his former students Dr. Yun Jeong Cha and Dr. Dae Seok Kim from KAIST appear as authors of this article published in October 2017: Advanced Functional Materials 27, 1703790, 2017.
* lab webpage : http://yoon.kaist.ac.kr/