Lithography-ready quantum dots

November 07, 2016 // By Julien Happich
Tackling the issues around high-resolution and large-scale patterning of quantum dots for display applications, a team of South Korean researchers has devised a new patterning process using modified quantum dots.

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

Doing so, they were able to demonstrate a repeatable and robust QD patterning process.

To demonstrate the new method, 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 4-inch substrate. They reported a maximum electroluminescence intensity of 23 770 cd/m 2 and square RGB pixels as narrow as 40µm.

The high-resolution and large-scale QD patterning process could be applicable to not only display, but also to practical photonic device research and development.

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