Tackling challenges of high-resolution, large-scale quantum dot patterning used in displays, Joon-Suh Park and fellow South Korean researchers have come up with a patterning process that uses modified quantum dots.

Published in Nano Letters, their study "Alternative Patterning Process for Realization of Large-Area, Full-Color, Active Quantum Dot Display" describes how researchers made hydrophilic quantum dots, so they would remain stable within the organic solvents used in conventional photolithography.

QD Patterning KIST 2016 (cr) Figure 1: High-resolution quantum dot patterning for displays.  

The researchers also leveraged electric charges created in the substrate to help the quantum dots adhere via electrostatic forces, enabling the researchers to control the thickness of the QD patterns at each position through charge-assisted layer-by-layer assembly.

Doing so, they were able to demonstrate a repeatable and robust QD patterning process. The researchers fabricated a display of the screen-print "Marilyn Monroe 1967" by Andy Warhol using red, green, violet and yellow quantum dots on a four-inch substrate. They reported a maximum electroluminescence intensity of 23,770cd/m² and square RGB pixels as narrow as 40µm.

The high-resolution, large-scale QD patterning process could be applicable to not only display but also photonic device R&D.