MIT engineers have utilized DNA origami scaffolds to create precisely structured arrays of quantum rods, which have the potential to enhance TVs and virtual reality devices. While flat screen TVs incorporating quantum dots are already available commercially, it has been more challenging to create arrays of quantum rods for commercial devices. Quantum rods can control both the polarization and color of light, thus generating 3D images for virtual reality devices. The researchers at MIT have devised a new method to assemble arrays of quantum rods using scaffolds made of folded DNA. By depositing quantum rods onto a DNA scaffold in a highly controlled manner, the scientists can regulate their orientation, which is crucial in determining the polarization of light emitted by the array. This technique facilitates the addition of depth and dimension to virtual scenes. According to Mark Bathe, an MIT professor of biological engineering and the senior author of the study, aligning quantum rods at the nanoscale so that they all point in the same direction has been a challenge. However, when they are all pointing in the same direction on a 2D surface, they exhibit the same properties in terms of their interaction with light and their ability to control its polarization. The lead authors of the research paper are MIT postdocs Chi Chen and Xin Luo. The study was published in Science Advances and other authors include Robert Macfarlane, an associate professor of materials science and engineering; Alexander Kaplan Ph.D.; and Moungi Bawendi, the Lester Wolfe Professor of Chemistry. Over the past 15 years, researchers at MIT, led by Bathe, have been at the forefront of designing and fabricating nanoscale structures made of DNA, also known as DNA origami. DNA, being a highly stable and programmable molecule, is an ideal building material for creating tiny structures that can be used in various applications such as drug delivery, biosensors, and scaffolds for light-harvesting materials. Bathe’s lab has developed computational methods that allow researchers to input a desired nanoscale shape, following which the program calculates the DNA sequences needed for self-assembly into the desired shape. The lab has also developed scalable fabrication methods incorporating quantum dots into DNA-based materials. Building on their prior work, the researchers collaborated with Macfarlane’s lab to address the challenge of arranging quantum rods into 2D arrays, which is more difficult since the rods need to be aligned in the same direction. Existing methods that create aligned arrays of quantum rods, such as mechanical rubbing or applying an electric field to sweep the rods in one direction, have had limited success. High-efficiency light emission requires the rods to be at least 10 nanometers apart from each other to prevent suppression of their neighbors’ light-emitting activity. The researchers have devised a method to attach quantum rods to diamond-shaped DNA origami structures, which can be built at the right size to maintain this distance. These DNA structures are then attached to a surface and fit together like puzzle pieces. The first step in making this approach work was finding a way to attach DNA strands to the quantum rods. Chen developed a process involving emulsifying DNA into a mixture with the quantum rods, followed by rapidly dehydrating the mixture, enabling the DNA molecules to form a dense layer on the surface of the rods. This process takes just a few minutes, much faster than existing methods, which is crucial for enabling commercial applications. The DNA strands then act as Velcro, helping the quantum rods stick to a DNA origami template, which forms a thin film that coats a silicate surface. The researchers now aim to create wafer-scale surfaces with etched patterns, allowing them to scale up their design for device-scale arrangements of quantum rods for various applications. The ability to control the sizes, shapes, and placement of these quantum rod arrays opens up possibilities for different electronic applications, according to Macfarlane. The researchers emphasize that DNA is an attractive manufacturing material as it can be biologically produced, making it scalable and sustainable in line with the emerging U.S. bioeconomy. The next steps involve solving some remaining challenges, such as switching to environmentally safe quantum rods, to translate this work into commercial devices.
Link to the original article: [https://phys.org/news/2023-08-arrays-quantum-rods-tvs-virtual.html](https://phys.org/news/2023-08-arrays-quantum-rods-tvs-virtual.html)
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Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
