MIT scientists conceive of quantum rods for 3D screens

“When they’re all pointing in the same direction on a 2D surface, then they all have the same properties of how they interact with light and control its polarization.”

The new scaffolding is also known as DNA origami. Bathe’s lab has engineered computational methods that calculate the sequences of DNA that will self-assemble into the right shape simply by entering a target nanoscale shape. 

“The quantum rods sit on the origami in the same direction, so now you have patterned all these quantum rods through self-assembly on 2D surfaces, and you can do that over the micron scale needed for different applications like microLEDs,” Bathe further explained. 

“You can orient them in specific directions that are controllable and keep them well-separated because the origamis are packed and naturally fit together, as puzzle pieces would.”

As part of their research, the scientists had to conceive of a method to attach DNA strands to the quantum rods. They engineered a process that involves emulsifying DNA into a mixture with the quantum rods, then rapidly dehydrating the mixture. This system takes only mere minutes and results in the DNA molecules forming a dense layer on the surface of the rods.

A unique aspect

“The unique aspect of this method lies in its near-universal applicability to any water-loving ligand with affinity to the nanoparticle surface, allowing them to be instantly pushed onto the surface of the nanoscale particles. By harnessing this method, we achieved a significant reduction in manufacturing time from several days to just a few minutes,” MIT postdoc Chi Chen said.

The researchers are now seeking to scale their design to device-scale arrangements of quantum rods for a variety of applications, beyond the conventional augmented reality/virtual reality uses.

“The method that we describe in this paper is great because it provides good spatial and orientational control of how the quantum rods are positioned. The next steps are going to be making arrays that are more hierarchical, with programmed structure at many different length scales. The ability to control the sizes, shapes, and placement of these quantum rod arrays is a gateway to all sorts of different electronics applications,” Robert Macfarlane, an associate professor of materials science and engineering, said.

“DNA is particularly attractive as a manufacturing material because it can be biologically produced, which is both scalable and sustainable, in line with the emerging U.S. bioeconomy. Translating this work towards commercial devices by solving several remaining bottlenecks, including switching to environmentally safe quantum rods, is what we’re focused on next,” Bathe added.