MIT engineers have developed a novel method to assemble arrays of quantum rods, which could be integrated into LEDs to enhance televisions or virtual reality (VR) devices.

Quantum Rods

According to MIT News, quantum rods, which are elongated counterparts to quantum dots, have proven challenging to incorporate into commercial devices.

These rods have the unique ability to control both light polarization and color, making them capable of generating 3D images for VR applications. Researchers achieved this breakthrough by utilizing DNA scaffolds to precisely arrange quantum rods in arrays.

By depositing quantum rods onto DNA scaffolds in a controlled manner, the researchers managed to regulate their orientation, a crucial factor in determining the polarization of emitted light. This breakthrough could significantly enhance the depth and dimensionality of virtual scenes.

Mark Bathe, a professor of biological engineering at MIT, highlighted the challenge of aligning quantum rods on a nanoscale to ensure uniform light interaction properties.

The approach developed by the MIT team involves using DNA structures, particularly diamond-shaped DNA origami structures, to attach quantum rods. These DNA structures are then positioned on surfaces, forming patterns like puzzle pieces.

"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 said in a statement.

"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," he added.

The method overcomes previous limitations that attempted to create aligned arrays of quantum rods using mechanical rubbing or electric fields. The researchers' method maintains a minimum distance of 10 nanometers between rods to prevent interference with each other's light emission.

Attaching DNA to Quantum Rods

Chi Chen and Xin Luo, the paper's lead authors, designed a process to attach DNA strands to quantum rods. This process involves emulsifying DNA into a mixture with the quantum rods and rapidly dehydrating the mix, allowing the DNA to form a dense layer on the rod's surface.

This approach reduces manufacturing time significantly, from several days to a few minutes. The researchers aim to scale their design for various applications, including micro LEDs and augmented reality/virtual reality.

The ability to control quantum rod arrays' size, shape, and placement opens doors to diverse electronics applications. This work aligns with the emerging US bioeconomy, as DNA is biologically producible, scalable, and sustainable.

The researchers aim to address remaining challenges, such as transitioning to environmentally safe quantum rods, to advance their work toward commercial devices.

"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," Chen said in a statement.

The findings of the team were published in the journal Science Advances.