Quantum dot OLEDs fabbed via spin coating

September 1, 2011 — University of Florida materials science and engineering (MSE) researchers developed a manufacturing process for quantum dot (QD) light emitting diodes (LEDs) that is lower cost and higher volume than previous attempts. A start-up company, NanoPhotonica, has licensed the technology and is creating a technology development program to capitalize on the manufacturing breakthrough.

The team solution-processed the LEDs, as opposed to tweaking semiconductor manufacturing processes, said Jiangeng Xue, the research leader and an associate professor of materials science and engineering. They focused on improving existing organic LEDs (OLEDs), which comprise multiple layers of organic materials, such as polymer plastics.

Paul Holloway, distinguished professor of materials science and engineering at UF, led a team developing the quantum dot side of the research. QDs combine sulfur, zinc, selenium and cadmium atoms and emit colored light when electrified. QDs can be fabbed in different sizes to modulate the light color.

Instead of building the hybrid LED via vauum deposition (organic layers) and spin coating (QDs), the teams created a patented device structure that eliminates vacuum deposition and relies solely on spin coating to deposit all the particles and molecules needed for the LED. Device efficiency and lifetime improved compared to previously reported QD-based LED devices, the researchers assert.

The teams will continue the research to investigate continuous roll-to-roll (R2R) manufacturing or other printing/coating processes that may offer more efficiency and lower costs. "That will remain as a future research and development topic for the university and NanoPhotonica," Xue said.

The QD LEDs could be integrated into large-area flat panel displays or solid state lighting applications.

Results are published in the current online issue of the journal Nature Photonics. Access it here: http://www.nature.com/nphoton/journal/v5/n9/full/nphoton.2011.171.html

Other co-authors of this article are Lei Qian and Ying Zheng, two postdoctoral fellows who worked with the professors on this research. The UF research teams received funding from the Army Research Office, the U.S. Department of Energy, and the Florida Energy Systems Consortium.

Courtesy of John Dunn, Jiangeng Xue, and Paul Holloway, www.ufl.edu

Also read: Report from the Organic Electronics Workshop

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