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JST Press Release

December 18, 2014
Japan Science and Technology Agency (JST)
5-3, Yonbancho, Chiyoda-ku, Tokyo 102-8666

Solution-Processed-Multilayer Small-Molecule Light-Emitting Devices: White Emission with High Efficiency

Recent developments in the field of p-conjugated polymers have led to considerable improvements in the performance of solution-processed organic light-emitting devices (OLEDs). However, further improving efficiency is still required to compete with other traditional light sources. We demonstrate efficient solution-processed multilayer OLEDs using small molecules. On the basis of estimates from a solvent resistance test of small host molecules, we demonstrate that covalent dimerization or trimerization instead of polymerization can afford conventional small host molecules sufficient resistance to alcohols used for processing upper layers. This allows us to construct multilayer OLEDs through subsequent solution-processing steps, achieving record-high power efficiencies of 36, 52 and 34 lm W-1 at 100 cd m-2 for solution-processed blue, green and white OLEDs, respectively, with stable electroluminescence spectra under varying current density. We also show that the composition at the resulting interface of solution-processed layers is a critical factor in determining device performance.

Researcher Information

S-Innovation (Strategic Promotion of Innovative Research and Development)
R&D theme: Organic Electronics "Development of printed and flexible OLED panels for general lighting"

Journal Information

Naoya Aizawa, Yong-Jin Pu, Michitake Watanabe, Takayuki Chiba, Kazushige Ideta, Naoki Toyota, Masahiro Igarashi, Yoshiyuki Suzuri, Hisahiro Sasabe, and Junji Kido. "Solution-processed multilayer small-molecule light-emitting devices with high-efficiency white-light emission". Nature Communications, Published online 18 December 2014, doi: 10.1038/ncomms6756.


[About Research]
Prof. Junji Kido
Department of Organic Device Engineering, Yamagata University

Prof. Yong-Jin Pu
Department of Organic Device Engineering, Yamagata University

[About Program]
Department of Industry-Academic Collaboration, JST


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