[20p-W521-1~16] 12.4 Organic light-emitting devices and organic transistors

△ [20p-W521-3] Development of 2,2′-Bipyridine-Based Electron-Transport Materials with Horizontal Orientation Induced by Intra- and Intermolecular Hydrogen Bonds

〇(D)Yuichiro Watanabe¹, Hisahiro Sasabe^1,2, Satoru Ohisa^1,2, Tomoyuki Koganezawa³, Hiroshi Katagiri^1,2, Daisuke Yokoyama^1,2, Junji Kido^1,2 (1.Yamagata Univ., 2.ROEL, 3.JASRI)

Keywords:electron transport material,molecular orientation,hydrogen bond

To boost the performances of organic light-emitting devices (OLEDs), one of the most promising approaches from a materials chemistry viewpoint is the use of thin solid films with horizontal molecular orientations. In this work, we developed 2,2′-bipyridine-skeleton-based electron-transport materials (ETMs) end-capped with 3,5-dipyridylphenyl groups with the objective of preparing films with horizontal molecular orientations for use in high-performance OLEDs. These compounds (4,4′-BPy3 and 6,6′-BPy3) afforded highly oriented films and were used in fac-tris(2-phenylpyridine)iridium(III)-based OLEDs as an electron-transport layer (ETL). The optimized device exhibited low operating voltages of 2.8 and 3.2 V at luminances of 100 and 1000 cd m⁻², respectively. At 1000 cd m⁻², this device exhibited a power efficiency of 74 lm W⁻¹ and an external quantum efficiency of 21%