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OLED displays and solid-state lightings in mass production, coming soon

Researchers develop highly efficient, solution-processed fluorescence organic light-emitting diodes using

Date:
March 1, 2016
Source:
Pohang University of Science & Technology (POSTECH)
Summary:
Scientists have fabricated highly-efficient, solution-processed fluorescence organic light-emitting diodes using pure-organic thermally-activated delayed-fluorescence emitters.
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A team led by Prof. Tae-Woo Lee (Dept. of Materials Science and Engineering) at POSTECH have fabricated highly-efficient, solution-processed fluorescence organic light-emitting diodes (OLEDs) using pure-organic thermally-activated delayed-fluorescence (TADF) emitters. The research was published in Advanced Materials journal.

Conventional OLEDs use the phosphorescent emitters which have shown high internal quantum efficiency (IQE) of nearly 100%. However, they should incorporate precious heavy metals such as iridium and platinum into phosphorescent metal-complexes; these limit their commercialization. In order to overcome these disadvantages, the research team uses pure-organic TADF emitters which can show a very high IQE of nearly 100% without precious metals. Furthermore, TADF emitters have advantages of easy synthesis using pure-organic molecules and versatile molecular design, thus, reduce the synthesis cost.

They also introduced the inexpensive, simple solution-process to fabricate the TADF-OLEDs by solving fundamental problems which limit the high efficiency in solution processed TADF-OLEDs. A multi-functional buffer hole injection layer (Buf-HIL) that can increase the hole injection capability to the emitting layer (EML) due to its high work function, and also improve the luminescence efficiency of TADF-OLEDs by preventing exciton quenching at the HIL/EML interface was employed. Furthermore, new polar aprotic solvent improved the device efficiency by improving the solubility of pure-organic TADF emitters, reducing the surface roughness and the aggregation of dopants, and managing the exciton quenching in the emitting layer.

This improvement in solution processed TADF-OLEDs will remedy the disadvantages of a complex and expensive vacuum-deposition process and thus lower the production cost of the devices. It is of prime importance to reduce the production cost of the devices from the perspective of industrial mass-production of OLED displays and solid-state lightings.

Prof. Tae-Woo Lee mentioned, "This technology is a big leap toward the development of inexpensive and solution-processed OLED displays and solid-state lights because this method uses only low-cost pure-organic molecules and simple solution process to realize the extremely high efficiency solution-processed OLEDs."

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP), and by the Center for Advanced Soft-Electronics funded by the Ministry of Science, ICT and Future Planning as Global Frontier Project.


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Materials provided by Pohang University of Science & Technology (POSTECH). Note: Content may be edited for style and length.


Journal Reference:

  1. Young-Hoon Kim, Christoph Wolf, Himchan Cho, Su-Hun Jeong, Tae-Woo Lee. Highly Efficient, Simplified, Solution-Processed Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diodes. Advanced Materials, 2016; 28 (4): 734 DOI: 10.1002/adma.201504490

Cite This Page:

Pohang University of Science & Technology (POSTECH). "OLED displays and solid-state lightings in mass production, coming soon: Researchers develop highly efficient, solution-processed fluorescence organic light-emitting diodes using." ScienceDaily. ScienceDaily, 1 March 2016. <www.sciencedaily.com/releases/2016/03/160301131109.htm>.
Pohang University of Science & Technology (POSTECH). (2016, March 1). OLED displays and solid-state lightings in mass production, coming soon: Researchers develop highly efficient, solution-processed fluorescence organic light-emitting diodes using. ScienceDaily. Retrieved September 25, 2016 from www.sciencedaily.com/releases/2016/03/160301131109.htm
Pohang University of Science & Technology (POSTECH). "OLED displays and solid-state lightings in mass production, coming soon: Researchers develop highly efficient, solution-processed fluorescence organic light-emitting diodes using." ScienceDaily. www.sciencedaily.com/releases/2016/03/160301131109.htm (accessed September 25, 2016).