Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials.
Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (~97.5 cd/A, ~35.5% photons per electron), green (~101.5 cd/A, ~29.0% photons per electron), and white (~74.2 cd/A, ~28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices.
Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyungbuk 790-784, Republic of Korea.; Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
Tae-Hee
TH
Han
Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyungbuk 790-784, Republic of Korea.
Mi-Ri
MR
Choi
Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Gyeongnam, Republic of Korea.
Chan-Woo
0000-0001-6219-4101
CW
Jeon
Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Gyeongnam, Republic of Korea.
Yun-Hi
YH
Kim
School of Materials Science and Engineering and Engineering Research Institute, Gyeongsang National University, Gyeongnam, Republic of Korea.
Soon-Ki
SK
Kwon
Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
Tae-Woo
TW
Lee
Organic light-emitting diodes (OLEDs); electron-transporting host; solution-processed OLEDs