The organic light-emitting devices (OLEDs) comprising multiple light-emitting units (LEUs) stacked in series through charge generation layers (CGLs), called tandem OLEDs, have been fabricated to achieve a high luminance and long operational lifetime simultaneously. We developed the fully solution-processed green and white tandem OLEDs using small molecule phosphorescent materials and their record breaking high efficiency. The ZnO nanoparticle / aliphatic amine polymer (PEIE) bilayer serves as the EIL in each LEU, and poly (3,4-ethylenedioxythiophene) : poly (styrenesulfonate) (PEDOT : PSS) is used as the interconnecting conductive layer. Successfully fabricated green and white phosphorescent stacked OLEDs exhibit nearly a twofold higher efficiency than either of the component LEUs.
JST S-Innovation (Strategic Promotion of Innovative Research and Development)
R&D Theme “Development of new electronics based on organic materials”
R&D Project “Development of printed and flexible OLED panels for general lighting”
Takayuki Chiba, Yong-Jin Pu, and Junji Kido. “Solution-Processed White Phosphorescent Tandem Organic Light-Emitting Devices”. Advanced Materials, Published online 15 July 2015, doi: 10.1002/adma.201501866.
Takayuki Chiba, Assistant Professor, Ph.D
Yong-Jin Pu, Associate Professor, Ph.D
Junji Kido, Professor, Ph.D
Department of Organic Device Engineering, Research Center for Organic Electronics, Yamagata University
Department of Industry-Academic Collaboration, JST