[20a-145-1~12] 12.4 Organic light-emitting devices and organic transistors

△ [20a-145-2] Solution-Processed Small-Molecule Phosphorescent Tandem Organic Light-Emitting Devices

〇Tatsuya Takahshi¹, Satoru Ohisa^1,2,3, Masahiro Igarashi^2,3, Hitoshi Fukuda¹, Tatsuya Hikichi¹, Emi Ueki^2,3, Takayuki Chiba^1,2,3, Yong-Jin Pu^1,2,3, Junji Kido^1,2,3 (1.Grad. Schl. of Org. Mater. Sci., Yamagata Univ., 2.Research Center for Organic Electronics (ROEL), 3.Frontier Center for Organic Materials (FROM))

Keywords:Tandem Organic Light-Emitting Devices

Recently, solution-processed polymer tandem organic light-emitting devices (OLEDs) comprising multiple light-emitting units connected by carrier generation layers have been reported as a promising way to realize long lifetime solution-processed OLEDs. However, those both with high device efficiency and long lifetime have been reported yet. In this work, we report the development of a stable solution-processed small-molecule phosphorescent tandem OLEDs, in which ten-layers were formed by solution-processing. We newly developed solvent-tolerant small molecule host materials with indolocarbazole, phenylcarbazole, and triazine units for phosphorescent EML. These materials showed high tolerance to methanol solvents. The upperlayer material on the EML is ZnO nanoparticle (NP), and it should be dispersed in methanol. The surface condition of the ZnO NPs was tuned to disperse them in methanol by modifying the conventional synthetic procedure. As a result, we succeeded in fabrication of solution-processed small-molecule orange phosphorescent tandem OLED comprising two light-emitting units.